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Exploration of the Value of Health-Related Quality-of-Life Information From Clinical Research and Into Clinical Practice

      Quality-of-life (QOL) instruments used in clinical research can provide important evidence to inform decisions about alternative treatments. This is particularly true when patients, such as those with cancer who are contemplating toxic chemotherapy, face tradeoffs between quantity of life and QOL or when the primary goal of therapy is to improve how patients feel. Surrogate measures (cardiac function, exercise capacity, bone density, tumor size) are inadequate substitutes for direct measurement of QOL. Quality-of-life measures will be most valuable when they comprehensively measure aspects of QOL that are both important to patients and likely to be influenced by therapy, when the QOL measurement instruments are valid (measuring what is intended) and responsive (able to detect all important changes, even if small), and when the results are readily interpretable (determining whether treatment-related changes are trivial, small but important, or large). Researchers are finding new, imaginative ways to help clinicians understand the magnitude of treatment impact on QOL. Additionally, QOL measures may be useful in clinical practice. Recent results from well-designed randomized controlled trials suggest that information on patient QOL provided to clinicians might, in some circumstances, result in benefits for these patients. Further investigation is warranted to confirm these observations and to define the particular combination of methods and settings most likely to yield important benefits.
      CI (confidence interval), CRQ (Chronic Respiratory Questionnaire), HRQL (health-related quality of life), NNT (number needed to treat), QOL (quality of life), RCT (randomized controlled trial)

      CLINICAL SCENARIO

      A 75-year-old man with severe chronic obstructive pulmonary disease is considering participation in a respiratory rehabilitation program. After many years of heavy smoking, the patient finally stopped but has severely impaired pulmonary function and dyspnea on minimal activity. He feels constantly tired and is often frustrated and anxious. Participation in the program would disrupt his routine and involve more than an hour of driving on most days for 4 weeks. He is wondering whether the program is worth the inconvenience and effort. “Doctor,” he asks the chest physician responsible for his care, “how much benefit will I get from this rehabilitation program?”
      The goal of this article is to explore the potential usefulness of health-related quality-of-life (HRQL) measures for clinicians. Clinicians and their patients may benefit from quality-of-life (QOL) measurement in 2 different ways. First, investigators who use QOL instruments in clinical research can provide important evidence to inform clinician and patient decision making about alternative treatments. Because of the potential usefulness of including QOL measures among the outcomes of many randomized controlled trials (RCTs), we present examples that illustrate how information about QOL can facilitate optimal medical management of patients.
      The second context in which QOL measures may provide added value arises from their use in day-to-day clinical practice. Asking patients to complete QOL questionnaires may prove an efficient way of gathering needed data about their functioning and well-being, alert clinicians to problems that require intervention, and ultimately improve patient outcomes. Only empirical data, ideally from RCTs, can determine whether QOL measures, when used in clinical practice, actually achieve any of these desirable outcomes. Some measures in some contexts will achieve all these goals, whereas other measures in other contexts may prove a waste of time and energy. Therefore, this article reviews the RCTs that have tested the impact of the use of QOL measures in clinical practice and presents the results. Before beginning an exploration of the potential usefulness of QOL measures, we specify exactly what we mean by QOL measurement information.

      WHAT IS HRQL?

      Quality of life is a broad concept that relates to all aspects of human life. When using the concept in health care, HRQL denotes a focus on the effects of illness and treatmenton QOL. Under the rubric of QOL, authors have used many different terms as if they were all the same thing, which has resulted in some confusion.
      There are a number of conceptual models to characterize QOL.
      • Ferrans CE
      Definitions and conceptual models of quality of life.
      Wilson and Cleary
      • Wilson IB
      • Cleary PD
      Linking clinical variables with health-related quality of life: a conceptual model of patient outcomes.
      developed one particularly helpful model (Figure 1) that focuses on 5 types of patient outcomes. The model begins with the most fundamental determinants of health status: biological and physiological variables. The next box is symptom status, which includes emotional, cognitive, and physical symptoms. The third is functional status, which addresses physical, social, role, and psychological functioning. The fourth box, general health perceptions, is a subjective evaluation that integrates all the preceding components. The fifth level is overall QOL, described in this model as subjective well-being, which means how happy or satisfied a person is with life as a whole.
      Figure thumbnail gr1
      FIGURE 1Relationship among measures of patient outcomes in a health-related quality-of-life conceptual model. From JAMA,
      • Ferrans CE
      Definitions and conceptual models of quality of life.
      with permission. Copyright 1995, American Medical Association, all rights reserved.
      The model highlights 3 important points. First, although the model begins with biological and physiological variables, the subsequent components are not limited to physical aspects of health. Experts generally agree that QOL depends on more than physical health status alone: illness can have a pervasive effect that seeps into all areas of life.
      • Guyatt GH
      • Feeny DH
      • Patrick DL
      Measuring health-related quality of life.
      The second point is that many of the components of this model require patient input. One cannot measure QOL without taking into account the patient's direct experience
      • Osoba D
      Lessons learned from measuring health-related quality of life in oncology.
      because it is important in the decision-making process as it relates to disease management. Third, it is worthwhile to distinguish among the various components of the model. In the literature, these components are often lumped together under the general heading of QOL, even though important differences exist among them. Different components of QOL produce different information by which to judge the efficacy of treatment.
      • Ferrans CE
      Definitions and conceptual models of quality of life.
      This report focuses on a broad conceptualization of QOL, which may include symptoms, functional status, health perceptions, and overall QOL. We distinguish among these components when separation of the component is important.

      CONCEPTUALIZATION AND ADDED VALUE OF QOL IN CLINICAL RESEARCH

      Clinicians offer treatment to their patients for 3 reasons. Clinicians encourage their patients to adhere to a treatment when they believe it (1) increases longevity, (2) prevents future morbidity, or (3) makes patients feel better. Feeling better includes avoiding discomfort (eg, pain, nausea, breathlessness), disability (ie, loss of function), and distress (ie, emotional problems).
      • Fletcher RH
      • Fletcher SW
      • Wagner EH
      For many years clinicians were willing to substitute physiological or laboratory tests for the direct measurement of the third end point, in part because of difficulty in measurement. However, during the past 20 years, clinicians have recognized the importance of direct measurement of how people are feeling and the extent to which they are able to function in daily activities, that is, QOL.
      Our discussion is designed for clinicians asking the question, “To what extent will alternative management strategies result in my patient feeling better or worse?” Other questions clinicians may ask before considering treatment include “How is my patient feeling now?” or “What issues or concerns are on my patient's mind?” Quality-of-life studies can help clinicians address these questions through an understanding of what average patients may be experiencing or the average patient's worries and preoccupations. For instance, what are the concerns of women who are receiving chemotherapy or hormonal therapy for breast cancer
      • Sutherland HJ
      • Lockwood GA
      • Boyd NF
      Ratings of the importance of quality of life variables: therapeutic implications for patients with breast cancer.
      • Ganz PA
      Impact of tamoxifen adjuvant therapy on symptoms, functioning and quality of life.
      • Hürny C
      • Bernhard J
      • Coates AS
      • et al.
      International Breast Cancer Study Group. Impact of adjuvant therapy on quality of life in women with node-positive operable breast cancer.
      or of men with prostate cancer?
      • Kornblith AB
      • Herr HW
      • Ofman US
      • Scher HI
      • Holland JC
      Quality of life of patients with prostate cancer and their spouses: the value of a database in clinical care.
      Attention to such studies may increase clinicians' understanding of patients' perspective and thus improve their communication with their patients.
      Still, the pragmatic clinician is primarily interested in ensuring that patients make the best decisions regarding their management. Keeping this goal in mind, when should the clinician be concerned about whether and how a trial included QOL measurement?

      Do We Need to be Concerned About QOL Outcomes?

      Early clinical trials did not include measurement of QOL. When should a clinician be concerned that investigators have not paid adequate attention to how patients feel?
      Most patients agree that, in most circumstances, prolonging their lives is a sufficient reason to accept a course of treatment. Previously, investigators demonstrated that 24-hour oxygen administration in patients with severe chronic airflow limitation reduced mortality.
      • Nocturnal Oxygen Therapy Trial Group
      Continuous or nocturnal oxygen therapy in hypoxemic chronic obstructive lung disease: a clinical trial.
      Since the intervention prolongs life, a subsequent report suggesting that more intensive oxygen therapy had little or no impact on QOL does not diminish enthusiasm for continuous oxygen administration.
      • Heaton RK
      • Grant I
      • McSweeny AJ
      • Adams KM
      • Petty TL
      Psychologic effects of continuous and nocturnal oxygen therapy in hypoxemic chronic obstructive pulmonary disease.
      Although feeling better is important to patients with heart failure, if angiotensin-converting enzyme inhibitors extend life to an appreciable degree, clinicians may be ready to recommend the treatment to patients even in the absence of known benefit to QOL.
      • Mulrow CD
      • Mulrow JP
      • Linn WD
      • Aguilar C
      • Ramirez G
      Relative efficacy of vasodilator therapy in chronic congestive heart failure: implications of randomized trials.
      Similarly, since milrinone shortens
      • Packer M
      • Carver JR
      • Rodeheffer RJ
      • PROMISE Study Research Group
      • et al.
      Effect of oral milrinone on mortality in severe chronic heart failure.
      life span, QOL assessments become irrelevant if clinicians are unwilling to prescribe a treatment that leads to premature death even if it improves QOL in the interval.
      Many life-prolonging interventions improve QOL. When treatment is associated with adverse effects, however, it may lead to important decrements in QOL. For example, the patient considering whether to undergo toxic cancer chemotherapy that will provide marginal gains in longevity faces a QOL benefit-cost tradeoff. At the extreme, an intervention such as mechanical ventilation may prolong the life of a patient in a vegetative state, but the patient's family may wonder if keeping their loved one alive is the best option.
      When the primary goal of treatment is to improve how people are feeling and physiological measures that correlate with patients' experiences are unavailable, measurement of some aspect of QOL becomes imperative. For example, clinicians would pay little attention to studies of anti-depressant medications that failed to measure patients' mood or to RCTs of antimigraine medication that failed to measure pain.
      Decisions are difficult when the relationship between physiological or laboratory measures and QOL outcomes is uncertain. Physicians have substituted physiological measures for QOL measurements (substitute end points) not because they have been uninterested in making patients feel better but because they assumed a strong link between physiological measurements and patients' functioning and well-being. Unfortunately, substitute end points such as bone density for fractures, homocysteine for coronary artery disease, and laboratory exercise capacity for ability to undertake day-to-day activities have often proved misleading.
      Changes in conventional measures of clinical status show only weak to moderate correlations with changes in QOL
      • Juniper EF
      • Svensson K
      • O'Byrne PM
      • et al.
      Asthma quality of life during 1 year of treatment with budesonide with or without formoterol.
      • Juniper EF
      • Norman GR
      • Cox FM
      • Roberts JN
      Comparison of the standard gamble, rating scale, AQLQ and SF-36 for measuring quality of life in asthma.
      and often fail to detect changes in QOL that are important to patients.
      • Juniper EF
      • Price DB
      • Stampone PA
      • Creemers JP
      • Mol SJ
      • Fireman P
      Clinically important improvements in asthma-specific quality of life, but no difference in conventional clinical indexes in patients changed from conventional beclomethasone dipropionate to approximately half the dose of extrafine beclomethasone dipropionate.
      In contrast, focus on physiological measures may lead clinicians to believe that a treatment is beneficial when in fact it does not change the way patients feel. For example, trials in patients with chronic lung disease have shown treatment effects on peak flow rates without improvement in QOL.
      • COMBIVENT Inhalation Solution Study Group
      Routine nebulized ipratropium and albuterol together are better than either alone in COPD.
      • Jaeschke R
      • Guyatt GH
      • Willan A
      • et al.
      Effect of increasing doses of beta agonists on spirometric parameters, exercise capacity, and quality of life in patients with chronic airflow limitation.
      If the primary goal of therapy is to improve the way patients feel, direct measurement of QOL and use of the results in clinical decision making become imperative. Clinicians can use the following litmus test: If the end points measured by the investigators were the only thing that changed, would patients be willing to take the treatment? In addition to change in clinical or physiological variables, patients require that they feel better or live longer. Consider the patient in the aforementioned “Clinical Scenario” section of this article. The focus of the patient's question is QOL, and only trials that measure the outcomes in which he is interested—dyspnea in daily life, fatigue, and emotional function—will be relevant to addressing his concerns. The following vignette provides a further example of this issue.
      A 70-year-old postmenopausal woman living on a limited income in Ontario, Canada, has, during the past 5 years, lost 5.08 cm (2 in) in height and experiencedmoderate, intermittent back pain. A radiograph of her vertebral spine shows 2 vertebral compression fractures. The physician informs the patient that she has osteoporosis, is likely to have repeated vertebral fractures, and is at higher risk than other women her age for long-bone fractures of the arm or hip. The physician suggests to the patient that she take cyclical etidronate, a drug that the Ontario drug benefit plan will largely pay for in persons older than 65 years.
      “What will the drug do for me?” asks the patient.
      “Well,” replies the physician, “a rigorous systematic review of randomized trials shows that etidronate will improve measurements of your bone density.”
      • Cranney A
      • Guyatt GH
      • Krolicki N
      • Osteoporosis Research Advisory Group (ORAG)
      • et al.
      A meta-analysis of etidronate for the treatment of postmenopausal osteoporosis.
      “I'm not impressed,” replies the patient, “unless those stronger bones improve my quality of life.”
      “Well,” the clinician points out, “the drug decreases your risk of having any more of those spine fractures by about a third. Now, I'm not sure how much of your back pain is actually due to the fractures, but there is a good chance that the drug can prevent some future back pain.”
      “Hmmm, that sounds promising. But will it do anything to prevent those more serious fractures you've warned me about, particularly hip fractures, which I've heard would have really serious consequences for my quality of life.”
      “Unfortunately, etidronate probably doesn't reduce long-bone fractures. I could offer you 2 other drugs that rigorous systematic reviews of randomized trials have shown do reduce those fractures, alendronate and risedronate, but they aren't covered by the drug plan.”
      • Cranney A
      • Guyatt GH
      • Griffith L
      • Wells G
      • Tugwell P
      • Rosen C
      Osteoporosis Methodology Group, Osteoporosis Research Advisory Group. IX: summary of meta-analyses of therapies for postmenopausal osteoporosis.
      What follows is a detailed discussion of exactly how large a risk of vertebral and long-bone fractures the patient is facing, the consequences of those fractures for the patient's QOL, exactly how much the drugs will reduce those risks, and how much the drugs would cost the patient. Bone density plays no further part in the discussion, and the functional and QOL consequences of fractures play a major part.

      Did the Investigators Use Adequate QOL Measures?

      The added value of QOL outcomes depends on their measurement properties (Table 1). Measures with limitations in reliability and validity may produce misleading results. Clinicians who use QOL results to guide their clinical care may benefit from a basic awareness of the key issues in determining QOL data credibility. The key points from a more extended clinician-oriented discussion are briefly summarized subsequently.
      • Guyatt G
      • Naylor CD
      • Juniper E
      • Heyland D
      • Jaeschke R
      • Cook D
      Quality of life.
      TABLE 1Issues to Consider in Evaluative Studies of QOL
      HRQL = health-related quality of life; QOL = quality of life.
      General issuesSpecific points to consider
      How can clinicians be sure that investigators have measured aspects of life that patients value?
      • Did the investigators present a detailed account of the content of their instruments?
      • Did the investigators ask the patients directly?
      • Did the investigators cite prior research about their instruments?
      Did the HRQL instruments work in the intended way?
      • Ensure the HRQL measures are
        • Valid—measure what they are intended to measure
        • Reliable—consistently measure HRQL in the absence of change
        • Responsive—instrument's ability to detect change
      Are there important aspects of HRQL that have been omitted?
      • Check if
        • Investigators have used generic instruments or disease-specific or condition-specific measures
          • Generic instruments are, on average, less powerful in detecting treatment effects than specific instruments but broadly assess different aspects of HRQL
          • Specific instruments are, on average, more powerful in detecting treatment effects but sometimes focus too narrowly to detect unanticipated treatment effects
      * HRQL = health-related quality of life; QOL = quality of life.
      How Can Clinicians Be Sure That Investigators Have Measured Aspects of Life That Patients Value? Investigators may show that the outcomes they have measured are important to patients by asking them directly. For example, in a study that examined QOL in patients with chronic airflow limitation, the investigators used a literature review and interviews with clinicians and patients to identify 123 items that reflected possible ways that patients' illness might affect their QOL.
      • Guyatt GH
      • Berman LB
      • Townsend M
      • Pugsley SO
      • Chambers LW
      A measure of quality of life for clinical trials in chronic lung disease.
      Then they asked 100 patients to identify the items that were problems for them and to indicate their importance. They found that the most important problem areas for patients were dyspnea during day-to-day activities and chronic fatigue. An additional area of difficulty was emotional function, including having feelings of frustration and impatience. Reference to other literature and inquiries of health care workers may also be important, particularly in pediatric or cognitively impaired populations.
      If the authors do not present direct evidence that their outcome measures are relevant and important to patients, they may cite prior research or provide detailed information on the content of their outcome measures. For example, the authors of an article that described an RCT of surgery vs watchful waiting for benign prostatic hyperplasia “assessed the degree to which urinary difficulties bothered the patients or interfered with their activities of daily living, sexual function, social activities, and general well-being.”
      • Wasson JH
      • Reda DJ
      • Bruskewitz RC
      • Elinson J
      • Keller AM
      • Henderson WG
      Veterans Affairs Cooperative Study Group on Transurethral Resection of the Prostate. A comparison of transurethral surgery with watchful waiting for moderate symptoms of benign prostatic hyperplasia.
      Few would doubt the importance of these items and, since patients in primary care often are untroubled by minor symptoms of benign prostatic hyperplasia, the importance of including them in the results of the trial. As a result, because the RCT showed that surgery was associated with improvement in symptoms and reduced interference with activities of daily living, clinicians should have little difficulty recommending surgery to a patient whose high priority is improving his or her QOL.
      Did the QOL Instruments Work in the Intended Way? Evidence concerning the performance of QOL measures is necessary for understanding the measurement properties of these instruments for clinical research. Investigators use QOL instruments in 2 distinct ways. One is to help clinicians distinguish between people who have a better or worse level of QOL (ie, discriminative instruments), and the other is to measure whether people feel better or worse over time (ie, evaluative instruments).
      • Guyatt GH
      • Kirshner B
      • Jaeschke R
      Measuring health status: what are the necessary measurement properties?.
      To be useful, discriminative instruments must be reliable. Differences among patients must be high in relationship to the variability within patients over time. By contrast, instruments used to evaluate change over time must be able to detect any important changes in the way patients are feeling, even if those changes are small. The term we use for the ability to detect change is responsiveness.
      An unresponsive instrument can result in a false-negative result in which the intervention improves how patients feel, but the instrument fails to detect the improvement. For example, researchers who conducted an RCT of a diabetes education program reported no changes in 2 measures of well-being, attributing the result to, among other factors, lack of integration of the program with standard therapy.
      • de Weerdt I
      • Visser AP
      • Kok GJ
      • de Weerdt O
      • van der Veen EA
      Randomized controlled multicentre evaluation of an education programme for insulin-treated diabetic patients: effects on metabolic control, quality of life, and costs of therapy.
      However, those involved in the educational program, in comparison to a control group, showed an improvement in knowledge and self-care, along with a decrease in feelings of dependence on physicians. Given these changes, another explanation for the investigators' finding of no difference between treatments in well-being might be inadequate responsiveness of the well-being measures.
      To be useful, QOL measures must be valid, in that they measure what they are intended to measure.
      • Hays RD
      • Revicki DA
      Reliability and validity, including responsiveness.
      Evaluating validity involves specifying and testing hypotheses about the relationship between the QOL instrument and other health-related measures, such as disease stage or severity, other QOL measures, or other clinical status measures. For example, we would expect that patients with lower treadmill exercise capacity generally will have more dyspnea in daily life than those with higher exercise capacity. When we are interested in evaluating change over time, we examine correlations of change scores. Patients who experience deterioration in their treadmill exercise capacity should, in general, show increases in dyspnea, whereas those whose exercise capacity improves should experience less dyspnea. The technical term for this process is testing an instrument's construct validity. Although investigators have identified other types of validity, clinicians should focus on evidence of construct validity when assessing the credibility of QOL measures used in clinical studies.
      Are There Important Aspects of HRQL That Have Been Omitted? Although investigators may have addressed QOL issues, they may not have done so comprehensively. Disease-specific (ie, instruments tailored to a specific disease, such as asthma, breast cancer, or arthritis), function-specific (eg, instruments that examine sleep or sexual function), or problem-specific (eg, pain or fatigue) QOL measures may comprehensively sample all aspects of QOL relevant to a specific illness and also be responsive, but they are unlikely to deal comprehensively with adverse effects.
      Consider, for instance, an RCT of methotrexate in 141 patients with chronically active Crohn disease despite at least 3 prior months of prednisone therapy.
      • Feagan BG
      • Rochon J
      • Fedorak RN
      • The North American Crohn's Study Group Investigators
      • et al.
      Methotrexate for the treatment of Crohn's disease.
      Patients who received methotrexate were twice as likely to be in clinical remission after 16 weeks of treatment as those who received placebo (39.4% vs 19.1%; P=.025), and actively treated patients received less prednisone and showed less disease activity. However, the decision to give methotrexate depends on the balance between the benefits and risks. Patients considering methotrexate treatment will likely wonder about how much better or worse they will feel while taking this medication. Therefore, without information about the effect of the medication on QOL, neither the clinician nor the patient can make a fully informed choice.
      In that study, the investigators administered the Inflammatory Bowel Disease Questionnaire, a valid and responsive measure of QOL tailored to the problems of patients with Crohn disease and ulcerative colitis.
      • Guyatt G
      • Mitchell A
      • Irvine EJ
      • et al.
      A new measure of health status for clinical trials in inflammatory bowel disease.
      Although the Inflammatory Bowel Disease Questionnaire measures some adverse effects of methotrexate (ie, nausea, lethargy), it does not assess other toxicity such as rash or mouth ulcers. What could the investigators have done to ensure they had captured relevant adverse effects?
      One option to capture the impact of adverse effects is to administer generic measures such as health profiles that yield scores for all domains of QOL (including, for example, mobility, self-care, and physical, emotional, and social function). However, generic instruments may only cover each QOL domain superficially and may also fail to detect the impact of adverse effects. In addition, the relatively superficial coverage of generic instruments limits their responsiveness. Generic instruments are, on average, less powerful in detecting treatment effects than specific instruments.
      • Wiebe S
      • Guyatt GH
      • Weaver B
      • Matijevic S
      • Sidwell C
      Comparative responsiveness of generic and specific quality-of-life instruments.
      For instance, in an RCT highly relevant to the dilemma of the patient with chronic obstructive pulmonary disease in the “Clinical Scenario” section, investigators conducted an RCT of respiratory rehabilitation vs conventional community care.
      • Goldstein RS
      • Gort EH
      • Stubbing D
      • Avendano MA
      • Guyatt GH
      Randomised controlled trial of respiratory rehabilitation.
      A number of generic measures of QOL, the Sickness Impact Profile, Quality of Well-Being Index, and the Standard Gamble, failed to distinguish between patients in the treatment and control groups. A condition-specific measure that focuses on the problems of patients with respiratory disability, the Chronic Respiratory Questionnaire (CRQ), demonstrated a decrease in dyspnea and fatigue and an improvement in emotional function in patients who participated in rehabilitation.
      • Guyatt GH
      • King DR
      • Feeny DH
      • Stubbing D
      • Goldstein RS
      Generic and specific measurement of health-related quality of life in a clinical trial of respiratory rehabilitation.
      If the patient in the “Clinical Scenario” section had only the results of the generic instruments, he would conclude that rehabilitation would not be worth the inconvenience and time. However, with the CRQ results, the question of rehabilitation remains open.

      How Can We Interpret the Magnitude of Effect on HRQL?

      Simply knowing the treatment-associated changes in scores in QOL questionnaires will not, without further information, be useful to clinicians. For instance, one clinical trial showed that patients with acute back pain who were prescribed bed rest had a mean score 3.9 points worse than those of control patients on the Owestry Back-Disability Index, a measure that focuses on disease-specific functional status.
      • Malmivaara A
      • Hakkinen U
      • Aro T
      • et al.
      The treatment of acute low back pain—bed rest, exercises, or ordinary activity?.
      Patients with severe rheumatoid arthritis allocated to treatment with cyclosporine had a mean disability score that was 0.28 unit better than that of control patients.
      • Tugwell P
      • Pincus T
      • Yocum D
      • et al.
      Methotrexate-Cyclosporine Combination Study Group. Combination therapy with cyclosporine and methotrexate in severe rheumatoid arthritis.
      This information alone leaves clinicians at a loss as to whether these differences are unimportant, small but important, of moderate magnitude, or reflect large and extremely important differences in efficacy among treatments.
      When reading the literature, clinicians must arrive at some general estimates of how a given therapy will affect QOL.
      • Guyatt GH
      • Osoba D
      • Wu AW
      • Wyrwich KW
      • Norman GR
      • Clinical Significance Consensus Meeting Group
      Methods to explain the clinical significance of health status measures.
      A number of methods are available for understanding the magnitude of QOL effects. Investigators may relate changes in QOL questionnaire scores to well-known functional measures (eg, the New York Heart Association functional classification), to clinical diagnosis (eg, the change in score associated with a diagnosis of major depressive disorder), to patients' global ratings of the magnitude of change they have experienced,
      • Juniper EF
      • Guyatt GH
      • Willan A
      • Griffith LE
      Determining a minimal important change in a disease-specific Quality of Life Questionnaire.
      or to the extent that patients rate themselves as feeling better or worse than other patients.
      • Redelmeier DA
      • Guyatt GH
      • Goldstein RS
      Assessing the minimal important difference in symptoms: a comparison of two techniques.
      These comparisons lead to estimates of change in QOL measures that, either for individual patients or for a group of patients, constitute trivial, small, medium, and large differences. For instance, the chest physician caring for the patient in the “Clinical Scenario” section will be interested in knowing that, by examining the relationship between global ratings of change and change in questionnaire score, investigators have established that an improvement or deterioration of 0.5 approximates a small but important difference in CRQ domains of dyspnea, fatigue, and emotional function, all measured on a 7-point scale.
      • Jaeschke R
      • Singer J
      • Guyatt GH
      Measurement of health status: ascertaining the minimal clinically important difference.
      This type of information still leaves a problem in the interpretation of results from clinical trials. For instance, if the mean difference between treatment and control on the CRQ is only 0.4, does this imply that we can dismiss the difference as unimportant to patients? Investigators have gained insight into this issue by examining the distribution of change in QOL in individual patients and by calculating the proportion of patients who achieved important QOL benefits from treatment and the associated numbers needed to treat (NNTs). For instance, in the RCT of respiratory rehabilitation mentioned earlier,
      • Goldstein RS
      • Gort EH
      • Stubbing D
      • Avendano MA
      • Guyatt GH
      Randomised controlled trial of respiratory rehabilitation.
      the mean differences between rehabilitation and standard community care were 0.60 in CRQ dyspnea, 0.45 in fatigue, and 0.40 in emotional function.
      The mean difference of 0.60, however, does not imply that every patient achieved a small but important difference. Similarly, differences below the threshold of 0.5, such as those seen in the rehabilitation study in fatigue and emotional function, do not imply that none of the patients experienced significant improvement. Rather, one would expect a distribution of benefits across patients, some achieving large improvements in QOL and others showing trivial or no gains.
      Investigators can examine the distribution of change in treatment and control groups to estimate the proportion of patients who benefited from respiratory rehabilitation. Examining their data, the investigators were able to estimate that 44% of the rehabilitation patients improved in day-to-day shortness of breath, whereas the comparable figure for the control group was 20%. Thus, the net proportion of patients who benefited from rehabilitation was 24%. The proportions of patients who benefited in terms of fatigue and emotional function were 23% and 30%, respectively.
      • Guyatt GH
      • Juniper EF
      • Walter SD
      • Griffith LE
      • Goldstein RS
      Interpreting treatment effects in randomised trials.
      One can take the inverse of these percentages to determine the NNT to achieve a small but important improvement in a single patient. For instance, one needs to treat 1/0.24 or approximately 4 patients to achieve an important reduction in dyspnea for a single patient. The comparable NNTs for fatigue and emotional function are 4 and 3, respectively. These numbers represent an impressive benefit compared with many other NNTs. For instance, we need to treat 100 average patients with myocardial infarction with tissue-type plasminogen activator rather than streptokinase to prevent 1 premature death, and we need to screen approximately 300 women for 10 years with mammography to prevent 1 premature breast cancer death.

      How Can QOL Data Help Patients Make Informed Decisions About Treatment?

      Even the most common problems of a chronic disease do not affect all those who are comparably afflicted. For instance, 92% of patients with inflammatory bowel disease experience frequent bowel movements, 82% experience abdominal cramps, 78% feel frustrated, and 76% feel depressed.
      • Mitchell A
      • Guyatt G
      • Singer J
      • et al.
      Quality of life in patients with inflammatory bowel disease.
      Descriptive data about patient experience may help clinicians determine what questions to ask about the patient's health status.
      Quality of life can provide unique information that leads to the choice of effective treatments, rejection of ineffective interventions, and clarification of the tradeoffs between management strategies with major benefits and health-related outcome costs. In the remainder of this section, we provide an example of each of these situations.
      After conducting a systematic search and applying explicit eligibility criteria, investigators can identify all relevant QOL studies that address a therapeutic controversy. They can then apply meta-analytic methods to QOL data to arrive at a robust estimate of treatment effects. For instance, a group of investigators have summarized the RCTs that compared structured respiratory rehabilitation to conventional community care for patients with severe chronic obstructive pulmonary disease.
      • Lacasse Y
      • Brosseau L
      • Milne S
      • et al.
      Pulmonary rehabilitation for chronic obstructive pulmonary disease.
      Their pooled estimate of effect showed an overall average effect slightly greater than the minimal important difference in dyspnea, fatigue, and emotional function. Through application of methods similar to those aforementioned for a single rehabilitation trial, results show that patients can anticipate that, on average, they will achieve small but important reductions in dyspnea and fatigue and improvement in emotional function from the program; chances of improving are approximately 50%.
      • Norman GR
      • Gwadry Sridhar F
      • Guyatt GH
      • Walter SD
      Relation of distribution- and anchor-based approaches in interpretation of changes in health-related quality of life.
      Although few studies provide information that is so easily interpreted, QOL investigators are working hard to improve the transparency of their presentation.
      Knowing that the likelihood of an important benefit from the program is approximately 50% is exactly what the patient in the “Clinical Scenario” requires. He now has to consider whether a 50-50 chance of achieving an important improvement in at least 1 of his problem areas—dyspnea, fatigue, anxiety, and depression—is worth the disruption in his life and the travel to the rehabilitation program. This decision will depend on his values and preferences.
      Another example of the application of QOL methods to improve clinical care is that orthopedic surgeons frequently recommend arthroscopic surgery with lavage and debridement for patients with painful osteoarthritis of the knee. Indeed, more than 650,000 of these procedures are performed each year in the United States,
      • Owings MF
      • Kozak LJ
      Ambulatory and inpatient procedures in the United States, 1996.
      at a cost of approximately $5000 per procedure. Investigators reported an RCT in which 180 patients underwent arthroscopy with debridement, arthroscopy with lavage, or placebo arthroscopy.
      • Moseley JB
      • O'Malley K
      • Petersen NJ
      • et al.
      A controlled trial of arthroscopic surgery for osteoarthritis of the knee.
      In the placebo arm, the knee was prepared and draped, 3 incisions were made in the skin, the surgeon asked for the instruments and manipulated the knee, saline was splashed to simulate lavage, and the patient was kept in the operating room for the amount of time required for debridement. Study personnel blinded to treatment group collected outcome data at 2 and 6 weeks and 3, 6, 12, 18, and 24 months postoperatively with a knee-specific pain scale, the pain and walking-bending domains of the Arthritis Impact Measurement Scales,
      • Meenan RF
      • Mason JH
      • Anderson JJ
      • Guccione AA
      • Kazis LE
      AIMS2: the content and properties of a revised and expanded Arthritis Impact Measurement Scales Health Status Questionnaire.
      and the 36-Item Short-Form Health Survey bodily pain and physical function domains.
      • Ware JE
      • Sherbourne CD
      The MOS 36-item short-form health survey (SF-36), I: conceptual framework and item selection.
      The investigators found no significant differences between treatment and placebo groups at any follow-up assessment. Patient reports of pain, physical functioning, or walking-bending were virtually identical in the 3 groups (Figure 2). The investigators specified minimal important differences for each outcome measure and noted that the confidence intervals (CIs) around the mean differences between groups excluded the minimal important difference. As previously noted, this approach does not absolutely exclude a subgroup of patients with an important difference, but it certainly makes important differences far less likely. The results of this trial, impossible to perform without use of QOL measures, should have an enormous impact on the use of this procedure and save many patients substantial cost and morbidity.
      Figure thumbnail gr2
      FIGURE 2Patient scores on the walking-bending subscale of the Arthritis Impact Measurement Scales from a randomized trial of surgical intervention for osteoarthritis of the knee. Error bars indicate 95% confidence intervals. From N Engl J Med,
      • Moseley JB
      • O'Malley K
      • Petersen NJ
      • et al.
      A controlled trial of arthroscopic surgery for osteoarthritis of the knee.
      ©2002, Massachusetts Medical Society, all rights reserved.
      The optimal treatment of patients with newly diagnosed prostate cancer remains uncertain. Until recently, clinicians relied on observational studies to guide their management. The first RCT, recently completed, compared radical prostatectomy with watchful waiting in 695 men with newly diagnosed early-stage prostatic carcinoma. The study included rigorous safeguards against bias.
      • Holmberg L
      • Bill-Axelson A
      • Helgesen F
      • et al.
      Scandinavian Prostatic Cancer Group Study Number 4. A randomized trial comparing radical prostatectomy with watchful waiting in early prostate cancer.
      Investigators established centralized and concealed randomization, conducted a blinded adjudication of cause of death, and achieved 100% follow-up for death and 87% for measurement of QOL
      • Steineck G
      • Helgesen F
      • Adolfsson J
      • Scandinavian Prostatic Cancer Group Study Number 4
      • et al.
      Quality of life after radical prostatectomy or watchful waiting.
      through a mean follow-up of 6.2 years for mortality and 4 years for QOL. They found a trend toward decreased all-cause mortality (18% vs 15%; relative risk, 0.83; 95% CI, 0.57-1.20; P=.31) and a decrease in prostate-specific death rates (9% vs 5%; relative risk, 0.50; 95% CI, 0.27-0.91; P=.02), favoring the prostatectomy group. The QOL results were mixed. Sexual dysfunction occurred in 45% of those in the watchful waiting group and in 80% of those who underwent radicalprostatectomy. Of those in the watchful waiting group, 21% experienced urinary leakage, as did 49% of those in the prostatectomy group. Urinary obstruction, defined as a weak urinary stream, occurred more often in those allocated to watchful waiting (44%) than those who underwent prostatectomy (28%). Bowel function, anxiety, depression, and well-being did not differ between the groups.
      These results suggest that men with different values will make different choices when presented with the dilemma of how to deal with newly diagnosed prostate cancer. The investigators put it well, “We cannot say that radical prostatectomy is better than watchful waiting for all men with localized prostate cancer. These alternatives are associated with complex and incommensurable outcomes, and each man must judge for himself which treatment is preferable.” In that trial, detailed QOL measurement provided critical evidence for men facing a difficult and important choice.

      ADDED VALUE OF QOL IN CLINICAL PRACTICE

      Using QOL in daily clinical practice is another way clinicians and their patients may benefit from measuring HRQL. The extent to which provision to health care professionals of formal information concerning the QOL of their patients improves the process and outcome of medical care is best assessed in RCTs in which clinicians are randomized to receive or not receive systematic feedback. We identified 2 previous systematic reviews that addressed this general issue,
      • Greenhalgh J
      • Meadows K
      The effectiveness of the use of patient-based measures of health in routine practice in improving the process and outcomes of patient care: a literature review.
      • Espallargues M
      • Valderas JM
      • Alonso J
      Provision of feedback on perceived health status to health care professionals: a systematic review.
      and 2 systematic reviews with a specific focus on routine feedback of psychiatric questionnaires to clinicians in nonpsychiatric settings.
      • Gilbody SM
      • House AO
      • Sheldon TA
      Routinely administered questionnaires for depression and anxiety: systematic review.
      • Gilbody SM
      • House AO
      • Sheldon T
      Routine administration of Health Related Quality of Life (HRQoL) and needs assessment instruments to improve psychological outcome-a systematic review.
      Of these, the review by Espallargues et al
      • Espallargues M
      • Valderas JM
      • Alonso J
      Provision of feedback on perceived health status to health care professionals: a systematic review.
      was far more comprehensive (it included all the RCTs identified in the other 3 reviews) and still met essential quality criteria for systematic reviews, including explicit eligibility criteria and selective inclusion of high-quality studies.
      Espallargues et al
      • Espallargues M
      • Valderas JM
      • Alonso J
      Provision of feedback on perceived health status to health care professionals: a systematic review.
      identified 21 RCTs in which patients or practitioners were randomly allocated to an intervention group that received provision of information about patients' reports of health status or a control group that received or practiced routine care.
      • Rubenstein LV
      • Calkins DR
      • Young RT
      • et al.
      Improving patient function: a randomized trial of functional disability screening.
      • Kazis LE
      • Callahan LF
      • Meenan RF
      • Pincus T
      Health status reports in the care of patients with rheumatoid arthritis.
      • White P
      • Atherton A
      • Hewett G
      • Howells K
      Using information from asthma patients: a trial of information feedback in primary care.
      • Linn LS
      • Yager J
      The effect of screening, sensitization, and feedback on notation of depression.
      • Yager J
      • Linn LS
      Physician-patient agreement about depression: notation in medical records.
      • Rand EH
      • Badger LW
      • Coggins DR
      Toward a resolution of contradictions: utility of feedback from the GHQ.
      • Reifler DR
      • Kessler HS
      • Bernhard EJ
      • Leon AC
      • Martin GJ
      Impact of screening for mental health concerns on health service utilization and functional status in primary care patients.
      • Dowrick C
      • Buchan I
      Twelve month outcome of depression in general practice: does detection or disclosure make a difference?.
      • Dowrick C
      Does testing for depression influence diagnosis or management by general practitioners?.
      • Hoeper EW
      • Nycz GR
      • Kessler LG
      • Burke Jr, JD
      • Pierce WE
      The usefulness of screening for mental illness.
      • Zung WWK
      • Magill M
      • Moore JT
      • George DT
      Recognition and treatment of depression in a family medicine practice.
      • German PS
      • Shapiro S
      • Skinner EA
      • et al.
      Detection and management of mental health problems of older patients by primary care providers.
      • Shapiro S
      • German PS
      • Skinner EA
      • et al.
      An experiment to change detection and management of mental morbidity in primary care.
      • Calkins DR
      • Rubenstein LV
      • Cleary PD
      • et al.
      Functional disability screening of ambulatory patients: a randomized controlled trial in a hospital-based group practice.
      • Mazonson PD
      • Mathias SD
      • Fifer SK
      • Buesching DP
      • Malek P
      • Patrick DL
      The mental health patient profile: does it change primary care physicians' practice patterns?.
      • Mathias SD
      • Fifer SK
      • Mazonson PD
      • Lubeck DP
      • Buesching DP
      • Patrick DL
      Necessary but not sufficient: the effect of screening and feedback on outcomes of primary care patients with untreated anxiety.
      • Brody DS
      • Lerman CE
      • Wolfson HG
      • Caputo GC
      Improvement in physicians' counseling of patients with mental health problems.
      • Magruder-Habib K
      • Zung WWK
      • Feussner JR
      Improving physicians' recognition and treatment of depression in general medical care: results from a randomized clinical trial.
      • Goldsmith G
      • Brodwick M
      Assessing the functional status of older patients with chronic illness.
      • Wasson J
      • Hays R
      • Rubenstein L
      • et al.
      The short-term effect of patient health status assessment in a health maintenance organization.
      • Rubenstein LV
      • McCoy JM
      • Cope DW
      • et al.
      Improving patient quality of life with feedback to physicians about functional status.
      • Moore JT
      • Silimperi DR
      • Bobula JA
      Recognition of depression by family medicine residents: the impact of screening.
      • Johnstone A
      • Goldberg D
      Psychiatric screening in general practice: a controlled trial.
      • Wagner AK
      • Ehrenberg BL
      • Tran TA
      • Bungay KM
      • Cynn DJ
      • Rogers WH
      Patient-based health status measurement in clinical practice: a study of its impact on epilepsy patients' care.
      • Callahan CM
      • Dittus RS
      • Tierney WM
      Primary care physicians' medical decision making for late-life depression.
      These trials focused on a wide variety of outcomes, including physicians' and patients' satisfaction, process of care (diagnosis and treatment), and outcomes (in particular, QOL). We updated and extended this review by systematically searching for all relevant studies published in the 1998-2003 period (not covered in the aforementioned review). We identified 8 additional relevant RCTs,
      • Detmar SB
      • Muller MJ
      • Schornagel JH
      • Wever LDV
      • Aaronson NK
      Health-related quality-of-life assessments and patient-physician communication: a randomized controlled trial.
      • Williams Jr, JW
      • Mulrow CD
      • Kroenke K
      • et al.
      Case-finding for depression in primary care: a randomized trial.
      • Wasson JH
      • Stukel TA
      • Weiss JE
      • Hays RD
      • Jette AM
      • Nelson EC
      A randomized trial of the use of patient self-assessment data to improve community practices.
      • Saitz R
      • Horton NJ
      • Sullivan LM
      • Moskowitz MA
      • Samet JH
      Addressing alcohol problems in primary care: a cluster randomized, controlled trial of a systems intervention: the screening and intervention in primary care (SIP) study.
      • Smith P
      The role of the general health questionnaire in general practice consultations.
      • Dailey YM
      • Humphris GM
      • Lennon MA
      Reducing patients' state anxiety in general dental practice: a randomized controlled trial.
      • Whooley MA
      • Stone B
      • Soghikian K
      Randomized trial of case-finding for depression in elderly primary care patients.
      • McCusker J
      • Verdon J
      • Tousignant P
      • de Courval LP
      • Dendukuri N
      • Belzile E
      Rapid emergency department intervention for older people reduces risk of functional decline: results of a multicenter randomized trial.
      • McCusker J
      • Dendukuri N
      • Tousignant P
      • Verdon J
      • Poulin de Courval L
      • Belzile E
      Rapid two-stage emergency department intervention for seniors: impact on continuity of care.
      and after excluding 2 of the studies previously included because of pseudorandomization,
      • Dowrick C
      Does testing for depression influence diagnosis or management by general practitioners?.
      • Callahan CM
      • Dittus RS
      • Tierney WM
      Primary care physicians' medical decision making for late-life depression.
      we included 27 studies.
      Six of these studies randomized individual physicians, 8 practices, and 13 patients. Quality scores on a scale of 0 to 7, in which higher numbers indicated better quality, ranged from 2.0 to 5.0, with a mean of 3.4. One serious quality problem is that most studies that randomized physicians or groups of physicians (and should therefore have used physicians or groups of physicians as the unit of analysis or at least accounted for clustering of outcomes across physicians or groups) had patients as the unit of analysis. This analytical error substantially increases the likelihood of false-positive findings. Another major problem is that most studies assessed multiple measures of outcome, even within category (ie, multiple measures of satisfaction, process, and outcome), while nevertheless retaining nominal threshold P values of .05. This also increases the likelihood of false-positive results.
      Of 12 RCTs that examined patient satisfaction, 5 found differences that favored the intervention group. Of 22 RCTs that assessed process of care, 14 detected some difference in process of care between intervention and control groups. Seven reported some impact on the diagnostic process, 2 on health services use, and 3 on advice, education, and counseling. Of the 16 studies that assessed patient outcomes, 7 found at least 1 outcome that was superior in the intervention compared with the control group.
      We have conducted a search for RCTs published since 2003 and identified 7 additional studies.
      • Brodey BB
      • Cuffel B
      • McCulloch J
      • et al.
      The acceptability and effectiveness of patient-reported assessments and feedback in a managed behavioral healthcare setting.
      • Velikova G
      • Booth L
      • Smith AB
      • et al.
      Measuring quality of life in routine oncology practice improves communication and patient well-being: a randomized controlled trial.
      • Fihn SD
      • McDonell MB
      • Diehr P
      • et al.
      Effects of sustained audit/feedback on self-reported health status of primary care patients.
      • MacArthur C
      • Winter HR
      • Bick DE
      • et al.
      Redesigning postnatal care: a randomised controlled trial of protocol-based midwifery-led care focused on individual women's physical and psychological health needs.
      • Hawkins EJ
      • Lambert MJ
      • Vermeersch DA
      • Slade KL
      • Tuttle KC
      The therapeutic effects of providing patient progress information to therapists and patients.
      • Lambert MJ
      • Whipple JL
      • Smart DW
      • Vermeersch DA
      • Nielsen SL
      • Hawkins EJ
      The effects of providing psychotherapists with feedback on patient progress during psychotherapy: are outcomes enhanced?.
      • Whipple JL
      • Lambert MJ
      • Vermeersch DA
      • Smart DW
      • Nielsen SL
      • Hawkins EJ
      Improving the effects of psychotherapy: the use of early identification of treatment failure and problem solving strategies in routine practice.
      Three of these RCTs focused on enhanced feedback to psychotherapists
      • MacArthur C
      • Winter HR
      • Bick DE
      • et al.
      Redesigning postnatal care: a randomised controlled trial of protocol-based midwifery-led care focused on individual women's physical and psychological health needs.
      • Hawkins EJ
      • Lambert MJ
      • Vermeersch DA
      • Slade KL
      • Tuttle KC
      The therapeutic effects of providing patient progress information to therapists and patients.
      • Lambert MJ
      • Whipple JL
      • Smart DW
      • Vermeersch DA
      • Nielsen SL
      • Hawkins EJ
      The effects of providing psychotherapists with feedback on patient progress during psychotherapy: are outcomes enhanced?.
      and were performed by the same group of investigators, consistently observing changes in both process and outcome-of-care variables.
      A study by Velikova et al
      • Velikova G
      • Booth L
      • Smith AB
      • et al.
      Measuring quality of life in routine oncology practice improves communication and patient well-being: a randomized controlled trial.
      that included 28 oncologists and 286 cancer patients yielded positive results. In this study, information about the patient's HRQL was associated with more frequent discussion about symptoms (without prolonging encounters) and with a better HRQL and emotional functioning at 6 months compared with the control patients. Positive findings were also observed in the studies by MacArthur et al
      • MacArthur C
      • Winter HR
      • Bick DE
      • et al.
      Redesigning postnatal care: a randomised controlled trial of protocol-based midwifery-led care focused on individual women's physical and psychological health needs.
      and more recently by Brodey et al
      • Brodey BB
      • Cuffel B
      • McCulloch J
      • et al.
      The acceptability and effectiveness of patient-reported assessments and feedback in a managed behavioral healthcare setting.
      but not in the large trial performed in the United States that included 985 clinicians and 15,346 patients with feedback of both generic and specific HRQL instruments for 2 years.
      • Velikova G
      • Booth L
      • Smith AB
      • et al.
      Measuring quality of life in routine oncology practice improves communication and patient well-being: a randomized controlled trial.
      If measurement of QOL with feedback to clinicians were resource free, even these mixed results might lead one to recommend the intervention with enthusiasm. Patients and clinicians often appreciate the information, and on occasion the information may influence the process and even the outcome of care. Unfortunately, the process involves resource use, and the constrained resources of the current health care environment suggest we should demand more from QOL feedback than high approval ratings from clinicians and patients. The less the increase in resources required, the less stringent would be the requirements for evidence of benefit of QOL measures in clinical practice: use of computer-based data collection may lower the resource burden and therefore encourage more widespread use.
      Effects of QOL feedback to clinicians on process and outcome have been inconsistent, and because of methodological problems, including incorrect unit of analysis and multiple comparisons, the estimates provided are likely biased in favor of the intervention. What we can say with confidence is that policymakers, administrators, or physician groups thinking of investing resources to collect QOL data from patients and provide summaries to physicians, at least using methods tested up to now, should not routinely anticipate important improvement in either the process of care or outcome. At the same time, there may be particular approaches and particular settings that would be more likely to produce success.
      Why did provision of information fail to improve management or outcome in so many studies? Routine patient interviews may provide physicians with all the information they need about patients' QOL to make appropriate management decisions. Alternatively, time constraints may prevent clinicians from conducting the exploration that, optimally, QOL information should trigger. Perhaps given adequate time, the additional information would ultimately lead to improved outcome. If either of these explanations is accurate, then changes in either the intervention or study design are unlikely to lead to subsequent positive trials.
      Other explanations for failure of the interventions include wrong choice of QOL instruments, inadequate time in educating clinicians about how to use the measures, suboptimal presentation of the information, necessity for clinicians having longer duration of experience with the instruments, or inadequate length of follow-up. These explanations, if accurate, would suggest that modifications to the interventions or to the study designs might yield more positive results. A deeper understanding coming from a theory-driven approach, combining knowledge of whether and how an intervention works, might best inform modifications in the interventions or study designs.
      • Greenhalgh J
      • Long AF
      • Flynn R
      The use of patient reported outcome measures in routine clinical practice: lack of impact or lack of theory?.
      Whatever the explanation, the currently available interventions may, in some situations, have important positive health effects. Research to discover the combination of patients, clinicians, and provision of information that one requires for important benefits remains worthwhile.

      CONCLUSION

      Recent findings from well-designed RCTs suggest that information provided to clinicians on their patients' QOL might, in some circumstances, result in benefits for these patients. Further investigation is warranted to confirm these observations and to define the particular combination of methods and settings most likely to yield important benefits. Since the major goal of most of our therapeutic interventions is to make patients feel better, QOL measurement is likely to become even more important in the future.

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      • CORRECTION
        Mayo Clinic ProceedingsVol. 82Issue 12
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          Incorrect use of initial: In the article by Guyatt et al entitled “Exploration of the Value of Health-Related Quality-of-Life Information From Clinical Research and Into Clinical Practice,” published in the October issue of Mayo Clinic Proceedings (Mayo Clin Proc. 2007; 82(10): 1229-1239), Dr Alonso prefers to use only his first initial: J. Alonso.
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