A 12-item short form of the Hip disability and Osteoarthritis Outcome Score (HOOS-12): tests of reliability, validity and responsiveness

OBJECTIVE

To evaluate reliability, validity and responsiveness of HOOS-12, a 12-item short form of the 40-item Hip disability and Osteoarthritis Outcome Score (HOOS). HOOS-12 provides Pain, Function and Quality of Life (QOL) scale scores and a summary hip impact score.

DESIGN

Data from 1,273 FORCE-TJR hip osteoarthritis (OA) patients who completed HOOS before and six and 12 months after total hip replacement (THR) were analyzed. HOOS-12 includes a pain frequency item and three items measuring pain during increasingly difficult (sitting/lying, walking, stairs) activities; function items about standing, rising from sitting, getting in/out of a car, and walking on an uneven surface; and the 4-item HOOS QOL scale. Percent computable scale scores, floor and ceiling effects, internal consistency reliability, validity (scale correlations, tests of known groups validity using one-way analysis of variance (ANOVA)), and responsiveness (effect sizes (ES), standardized response means (SRM)) were compared for HOOS-12, full-length HOOS, HOOS-PS and HOOS, JR.

RESULTS

Internal consistency reliability was above 0.70 for all HOOS-12 scales and above 0.90 for the HOOS-12 Summary score. Validity and responsiveness of HOOS-12 Pain, Function and QOL scales were satisfactory and reached similar conclusions as comparable full-length HOOS scales. The HOOS-12 Summary score was highly responsive in discriminating between groups who differed in global ratings of post-THR change in physical capabilities and had high ES and SRM standardized response means.

CONCLUSIONS

HOOS-12 was a reliable and valid alternative to HOOS in THR patients with moderate to severe OA and provided three domain-specific and summary hip impact scores with substantially reduced respondent burden.

Item selection for 12-item short forms of the Knee injury and Osteoarthritis Outcome Score (KOOS-12) and Hip disability and Osteoarthritis Outcome Score (HOOS-12)

OBJECTIVE

To develop 12-item short forms (KOOS-12, HOOS-12) of the 42-item Knee injury and Osteoarthritis Outcome Score (KOOS) and 40-item Hip disability and Osteoarthritis Outcome Score (HOOS) that represent the full-length instruments sufficiently to provide joint-specific pain, function and quality of life (QOL) domain and summary joint impact scores. This paper describes KOOS-12 and HOOS-12 item selection. Subsequent papers will examine KOOS-12 and HOOS-12 reliability, validity and responsiveness.

DESIGN

Items were selected based on qualitative information from patients, clinicians and KOOS/HOOS translators and analysis of data from 1,395 knee osteoarthritis (OA) and 1,281 hip OA patients from the FORCE-TJR cohort who completed KOOS or HOOS before and after total joint replacement (TJR). Item response theory models and computerized adaptive test (CAT) simulations were used to identify items that best measured patients' levels of pain and function pre- and post-TJR. KOOS-12/HOOS-12 items were selected based on content, coverage of a wide measurement range, high item information, item usage in CAT simulations, scale-level properties (reliability, validity, responsiveness), and qualitative information.

RESULTS

KOOS-12 and HOOS-12 each included a pain frequency item and three items measuring pain during increasingly difficult activities (sitting/lying, walking, up/down stairs); function items about standing, rising from sitting, getting in/out of a car, and twisting/pivoting (KOOS-12) or walking on an uneven surface (HOOS-12); and the original 4-item QOL scale.

CONCLUSIONS

This study demonstrated the benefits of examining patient-reported outcome measures using modern psychometric methods, to create short forms with diverse content that provide domain-specific and summary joint impact scores.

A 12-item short form of the Knee injury and Osteoarthritis Outcome Score (KOOS-12): tests of reliability, validity and responsiveness

OBJECTIVE

To evaluate reliability, validity and responsiveness of KOOS-12, a 12-item short form of the 42-item Knee injury and Osteoarthritis Outcome Score (KOOS) that provides Pain, Function and Quality of Life (QOL) scale scores and a summary knee impact score.

DESIGN

Data from 1,392 knee osteoarthritis (OA) patients from the FORCE-TJR research cohort who completed KOOS before and 6 and 12 months after total knee replacement (TKR) were analyzed. KOOS-12 includes a pain frequency item and three items measuring pain during increasingly difficult (sitting/lying, walking, stairs) activities; function items about standing, rising from sitting, getting in/out of a car, and twisting/pivoting; and the 4-item KOOS QOL scale. Percent computable scale scores, floor and ceiling effects, internal consistency reliability, validity (scale correlations, tests of known groups validity using one-way analysis of variance (ANOVA)) and responsiveness (effect sizes, standardized response means) were compared for the KOOS-12, full-length KOOS, KOOS-PS and KOOS, JR.

RESULTS

Internal consistency reliability was above 0.70 for all KOOS-12 scales and ≥0.90 for the KOOS-12 Summary score. Validity and responsiveness of KOOS-12 Pain, Function and QOL scales was satisfactory and reached similar conclusions as comparable full-length KOOS scales. The KOOS-12 Summary score was most responsive in discriminating between groups who differed in global ratings of post-TKR change in physical capabilities and had the highest effect sizes and standardized response means.

CONCLUSIONS

KOOS-12 was a reliable and valid alternative to KOOS in TKR patients with moderate to severe OA and provided three domain-specific and summary knee impact scores with substantially reduced respondent burden.

The responsiveness of headache impact scales scored using 'classical' and 'modern' psychometric methods: a re-analysis of three clinical trials

BACKGROUND

While item response theory (IRT) offers many theoretical advantages over classical test theory in the construction and scoring of patient based measures of health few studies compare scales constructed from both methodologies head to head.

OBJECTIVE

Compare the responsiveness to treatment of migraine specific scales scored using summated rating scale methods vs. IRT methods.

METHODS

The data came from three clinical studies of migraine treatment that used the Migraine Specific Quality of Life Questionnaire (MSQ). Five methods of quantifying responsiveness were used to evaluate and compare changes from pre- to post-treatment in MSQ scales scored using Likert and IRT scaling methods.

RESULTS

Changes in all MSQ scale scores from pre- to post-treatment were highly significant in all three studies. A single index scored from the MSQ using IRT methods was determined to be more responsive than any one of the MSQ subscales across the five methods used to quantify responsiveness. Across 13 of the 15 tests (5 responsiveness methods * 3 studies) conducted, the single index scored from the MSQ using IRT methods was the most responsive measure.

CONCLUSIONS

IRT methods increased the responsiveness of the MSQ to the treatment of migraine. The results agree with the psychometric evidence that suggest that it is feasible to score a single index from the MSQ using IRT methods. This approach warrants further testing with other measures of migraine impact.

A six-item short-form survey for measuring headache impact: the HIT-6

BACKGROUND

Migraine and other severe headaches can cause suffering and reduce functioning and productivity. Patients are the best source of information about such impact.

OBJECTIVE

To develop a new short form (HIT-6) for assessing the impact of headaches that has broad content coverage but is brief as well as reliable and valid enough to use in screening and monitoring patients in clinical research and practice.

METHODS

HIT-6 items were selected from an existing item pool of 54 items and from 35 items suggested by clinicians. Items were selected and modified based on content validity, item response theory (IRT) information functions, item internal consistency, distributions of scores, clinical validity, and linguistic analyses. The HIT-6 was evaluated in an Internet-based survey of headache sufferers (n = 1103) who were members of America Online (AOL). After 14 days, 540 participated in a follow-up survey.

RESULTS

HIT-6 covers six content categories represented in widely used surveys of headache impact. Internal consistency, alternate forms, and test-retest reliability estimates of HIT-6 were 0.89, 0.90, and 0.80, respectively. Individual patient score confidence intervals (95%) of app. +/-5 were observed for 88% of all respondents. In tests of validity in discriminating across diagnostic and headache severity groups, relative validity (RV) coefficients of 0.82 and 1.00 were observed for HIT-6, in comparison with the Total Score. Patient-level classifications based in HIT-6 were accurate 88.7% of the time at the recommended cut-off score for a probability of migraine diagnosis. HIT-6 was responsive to self-reported changes in headache impact.

CONCLUSIONS

The IRT model estimated for a 'pool' of items from widely used measures of headache impact was useful in constructing an efficient, reliable, and valid 'static' short form (HIT-6) for use in screening and monitoring patient outcomes.

Interpreting SF-36 summary health measures: a response

In response to questions raised about the "accuracy" of SF-36 physical (PCS) and mental (MCS) component summary scores, particularly extremely high and low scores, we briefly comment on: how they were developed, how they are scored, the factor content of the eight SF-36 subscales, cross-tabulations between item-level responses and extreme summary scores, and published and new tests of their empirical validity. Published cross-tabulations between SF-36 items and PCS and MCS scores, reanalyses of public datasets (N = 5919), and preliminary results from the Medicare Health Outcomes Survey (HOS) (N = 172,314) yielded little or no evidence in support of Taft's hypothesis that extreme scores are an invalid artifact of some negative scoring weights. For example, in the HOS, those (N = 432) with "unexpected" PCS scores worse than 20 (which, according to Taft, indicate better mental health rather than worse physical health) were about 25% more likely to die within two years, in comparison with those scoring in the next highest (21-30) category. In this test and in all other empirical tests, results of predictions supported the validity of extreme PCS and MCS scores. We recommend against the interpretation of average differences smaller than one point in studies that seek to detect "false" measurement and we again repeat our 7-year-old recommendation that results based on summary measures should be thoroughly compared with the SF-36 profile before drawing conclusions. To facilitate such comparisons, scoring utilities and user-friendly graphs for SF-36 profiles and physical and mental summary scores (both orthogonal and oblique scoring algorithms) have been made available on the Internet at www.sf-36.com/test.

Sleep problems, health-related quality of life, work functioning and health care utilization among the chronically ill

OBJECTIVES

To provide a comprehensive assessment of whether sleep problems among the chronically ill are associated with decrements in functional health and well-being, decreases in work functioning and increases in the use of health care services.

DESIGN

Cross-sectional survey of patients from the Medical Outcomes Study (MOS), an observational study of functional health and well-being. Chronically ill patients (n = 3484) were sampled from health maintenance organizations, large multi-specialty groups, and solo or single-specialty group practices in Boston, Los Angeles, and Chicago. Chronic illness subgroups include: clinical depression (n = 527), congestive heart failure (229), diabetes (n = 577), recent myocardial infarction (n = 170), hypertension (n = 2206), asthma (n = 84), back problems (n = 771), and arthritis (n = 672). ANCOVA analyses of the relationship between sleep problems and SF-36 scales and summaries were performed. In addition, a 'relative impact' analysis determined what scales or summaries were most associated with sleep problems.

MAIN OUTCOME MEASURES

Eight scales and two summary measures from the SF-36 Health Survey, work productivity and work quality measures and self-reports of health care utilization.

RESULTS

Comparing chronically ill patients with no sleep problems to those with mild, moderate, or severe sleep problems revealed a direct association between sleep problems and decrements in health-related quality of life (HRQOL) as measured by SF-36 scales and summaries (MANOVA F 24.1; d.f. 24; p < or = 0.0001). In addition, significant differences in HRQOL were found when comparing patients with and without sleep problems within most of the disease groups studied. The relative impact analysis revealed that measures of mental health and the mental health summary were most associated with sleep problem severity in the total sample and chronic disease subsets, in comparison with measures of physical health. In addition, monotonic relationships were found between severity of sleep problems and decreases in work productivity and increases in health care utilization, as expected.

CONCLUSIONS

The analyses revealed that sleep problems go hand in hand with poorer mental health, diminished work productivity and work quality and greater use of health care services. Sleep problems, therefore, may be a significant confounding factor in the interpretation of health outcomes among patients with chronic diseases.

Acute effects of fluoxetine versus placebo on functional health and well-being in late-life depression

In a randomized 6-week trial comparing fluoxetine with placebo, the Medical Outcomes Study 36-Item Short-Form Health Status Survey (SF-36) scales were used to measure the effects of treatment on functional health and well-being among elderly (age > or = 60 years) outpatients with major depression. In the fluoxetine and placebo groups, 261 and 271 patients, respectively, completed the SF-36 before treatment and at Weeks 3 and 6. Compared with national norms for individuals over age 60, study patients before treatment exhibited baseline decrements on the following SF-36 scales: mental health, role limitations due to emotional problems, social functioning, vitality, role limitations due to physical problems, and bodily pain. Analyses of SF-36 changed scores from baseline to Week 6 revealed that the fluoxetine group improved more than the placebo group across all scales. Differences in changes of scores between groups were significant (p < .05), favoring the fluoxetine group for the scales of mental health, role limitations due to emotional problems, physical functioning, and bodily pain. Improvements observed in the fluoxetine group were both clinically and socially significant.

Sustained virologic response is associated with improved health-related quality of life in relapsed chronic hepatitis C patients

Although evidence of virologic elimination, normalization of serum alanine aminotransferase levels, and reduction in liver inflammation are the principal therapeutic outcome goals in chronic hepatitis C patients, improvement in health-related quality of life (HQL) is also an important aspect of therapeutic outcome. In a recent report of chronic hepatitis C patients treated for 24 weeks with interferon, sustained virologic response (24 weeks post-treatment) was associated with improvement in HQL compared with nonresponse. We report on the relationship between sustained virologic response and Hepatitis Quality-of-Life Questionnaire (HQLQ) survey results of patients who relapsed after a previous course of interferon alfa who were subsequently treated with recombinant interferon alfa-2b (rIFN-alpha 2b) either alone or in combination with ribavirin. The HQLQ was administered at baseline, at treatment Weeks 12 and 24, and at follow-up Weeks 12 and 24. All patients received rIFN-alpha 2b 3 million International Units by subcutaneous injection three times weekly plus either oral ribavirin (1,000 or 1,200 mg) or placebo daily for 24 weeks. At baseline, patients scored lower than adjusted population norms in HQL. Relative to patients treated with rIFN-alpha 2b monotherapy, patients receiving combination therapy showed better HQL in 6 of 13 domains. Furthermore, sustained virologic response in either treatment group was associated with improvement in the scores of both generic and hepatitis-specific HQL survey domains. These results indicate that successful therapeutic resolution of hepatitis C infection improves HQL as assessed by generic and hepatitis C-specific measures of functional health and well-being. Furthermore, improvements in HQL outcome measures may predict reduced demand for health care resources and greater productivity in the workplace.

A new tool for monitoring asthma outcomes: the ITG Asthma Short Form

BACKGROUND

Asthma treatment has broadened from managing clinical markers to incorporate factors that are most meaningful to patients, collectively called health-related quality of life (HQL).

OBJECTIVE

To develop an asthma-specific HQL tool, meeting demands for brevity, usefulness and measurement precision.

METHODS

The 20-item Sydney Asthma Quality of Life Questionnaire (AQLQ) and six additional items were studied using factor analysis, reliability and validity tests among asthma patients 14 and older.

RESULTS

The 15-item Integrated Therapeutics Group Asthma Short Form (ITG-ASF) retains the validity of the AQLQ with improved scaling properties and interpretability. The ITG-ASF yields 6 scores: Symptom-Free Index, Functioning with Asthma, Psychosocial Impact of Asthma, Asthma Energy and Asthma-Confidence in Health and a Total. All items correlated 0.40 or higher with their hypothesized scales and passed discriminant validity tests, with scaling success rates from 75 to 100%. Reliability exceeded the minimum of 0.70 for group comparisons. Ceiling and floor effects were acceptable. Scales were valid in relation to changes in asthma severity and lung function. The best predictor of asthma severity (National Asthma Education and Prevention Program (NAEPP) staging) was the Symptom-Free Index. A Spanish translation is available, Chinese-American is forthcoming. The reading grade level is 4.8.

CONCLUSIONS

Development of the ITG-ASF was a data-driven process maximizing measurement precision and breadth while minimizing burden. The ITG-ASF is a brief, comprehensive and empirically valid tool that complements traditional markers of the outcomes of asthma care.

The effects of interferon alpha-2b in combination with ribavirin on health related quality of life and work productivity

BACKGROUND/AIMS

Interferon plus ribavirin is the most effective therapy for chronic hepatitis C. The aim of this study was to evaluate the effect of chronic hepatitis C and therapy on health-related quality of life and work functioning.

METHODS

Nine hundred and twelve patients with hepatitis C infection were randomized in a controlled trial of Interferon alpha 2b 3 MU tiw for 24 or 48 weeks plus ribavirin 1000-1200 mg or placebo. Questionnaire-based assessments of health-related quality of life and work functioning were performed before, during, and after treatment. Outcome measures included the SF-36 Health Survey and additional generic and specific scales. Work functioning was assessed as missed days, shorter hours or less productivity at work.

RESULTS

Pre-treatment, patients had significant impairment in five of eight SF-36 concepts compared to matched population norms. Sustained responders had a return to normal for four of these five concepts. Quality of life did not improve in non-responders. Improvements in histology, viral load or ALT values predicted improvements in quality of life. Sustained responders also had improvements in work functioning and productivity.

CONCLUSIONS

Hepatitis C patients had impaired quality of life. After combination therapy, sustained virologic responders achieved benefits in their quality of life and work functioning.

Determining minimally important changes in generic and disease-specific health-related quality of life questionnaires in clinical trials of rheumatoid arthritis

OBJECTIVE

To define clinically meaningful changes in 2 widely used health-related quality of life (HQL) instruments in studies of patients with rheumatoid arthritis (RA).

METHODS

Patients with RA (n = 693) who were enrolled in 2 double-blind, placebo-controlled clinical trials completed the Short Form 36 (SF-36) modified health survey and the Health Assessment Questionnaire (HAQ) disability index at baseline and 6-week followup assessments. Data on 5 RA severity measures were also collected at baseline and at 6 weeks (patient and physician global assessments, joint swelling and tenderness counts, and global pain assessment). Comparison of changes in the SF-36 scales and HAQ scores was made between groups of patients known to differ in the level of change on each RA severity measure.

RESULTS

With few exceptions, changes in the SF-36 and HAQ scores were different between patients who differed in the level of change on each RA severity measure. Changes in the SF-36 and HAQ scores were more strongly related to changes in the patient and physician global assessments and patient pain assessment than to changes in the joint swelling and tenderness counts.

CONCLUSION

Based on these results, minimally important changes in the SF-36 scales and HAQ disability scores were determined, which will be useful in interpreting HQL results in clinical trials.

Impact of changes in asthma severity on health-related quality of life in pediatric and adult asthma patients: results from the asthma outcomes monitoring system

The goals of asthma treatment have broadened beyond managing traditional clinical markers of disease severity, and now include a focus on benefits of treatment in terms that are most meaningful to patients. Measurement of both generic and disease-specific health-related quality of life (HQL) is advocated because each provides complementary information about how the condition affects everyday functioning and well-being and whether treatments have their intended effects. The purpose of this study was to determine the impact of changes in asthma severity (defined using NHLBI/NAEPP severity staging) on patient-assessed HQL. Two hundred and thirty-three pediatric asthma patients and 269 adult asthma patients were evaluated in a one-year observational study. Analyses were performed to compare the generic and asthma-specific scores for patients whose asthma severity improved, stayed the same, or worsened over one year. The asthma-specific scales are sensitive to changes in disease severity. Of the generic scales, those tapping areas of physical health are more affected than the mental/emotional scales. This confirms that HQL measures are responsive to changes in asthma severity. They complement traditional clinical markers used to evaluate changes in a patient's disease state and thus give the physician another useful tool in following the clinical progress of the child with asthma.

Profile of men randomized to the prostate cancer prevention trial: baseline health-related quality of life, urinary and sexual functioning, and health behaviors

PURPOSE

To describe men who agreed to be randomized to the Prostate Cancer Prevention Trial (PCPT), a 7-year, double-blind placebo-controlled study of the efficacy of finasteride in preventing prostate cancer.

METHODS

Comprehensive health-related quality-of-life data are presented for 18,882 randomized PCPT participants.

RESULTS

PCPT participants are highly educated, middle to upper income, and primarily white (92%). Participants reported healthy lifestyles. The mean American Urological Association Symptom Index score was well below the maximum entry score of less than 19; existing urinary symptoms were generally not bothersome. The scores for two sexual functioning scales could range from 0 to 100, with higher scores reflecting worse sexual functioning. The mean score for the Sexual Problem Scale was 19.2 out of 100, and the mean Sexual Activities Scale was 44.1 out of 100. Scores for seven of the eight Medical Outcomes Study 36-item Short-Form Health Survey scales (higher scores are better) were 10 to 20 points higher than those reported by a general population sample and differed minimally by race but not by age. Previously reported associations between sexual dysfunction and hypertension, diabetes, and depression were also observed. Men who never smoked reported less sexual dysfunction than did those who either had quit or still smoked.

CONCLUSION

Individuals who are likely to enroll in primary prevention trials have a high socioeconomic status, healthy lifestyle behaviors, and better health than the general population. These data help oncologists design chemoprevention trials with respect to the selection of health-related quality-of-life assessments and recruitment strategies.

Organizational and financial characteristics of health plans: are they related to primary care performance?

BACKGROUND

Primary care performance has been shown to differ under different models of health care delivery, even among various models of managed care. Pervasive changes in our nation's health care delivery systems, including the emergence of new forms of managed care, compel more current data.

OBJECTIVE

To compare the primary care received by patients in each of 5 models of managed care (managed indemnity, point of service, network-model health maintenance organization [HMO], group-model HMO, and staff-model HMO) and identify specific characteristics of health plans associated with performance differences.

METHODS

Cross-sectional observational study of Massachusetts adults who reported having a regular personal physician and for whom plan-type was known (n = 6018). Participants completed a validated questionnaire measuring 7 defining characteristics of primary care. Senior health plan executives provided information about financial and nonfinancial features of the plan's contractual arrangements with physicians.

RESULTS

The managed indemnity system performed most favorably, with the highest adjusted mean scores for 8 of 10 measures (P<.05). Point of service and network-model HMO performance equaled the indemnity system on many measures. Staff-model HMOs performed least favorably, with adjusted mean scores that were lowest or statistically equivalent to the lowest score on all 10 scales. Among network-model HMOs, several features of the plan's contractual arrangement with physicians (ie, capitated physician payment, extensive use of clinical practice guidelines, financial incentives concerning patient satisfaction) were significantly associated with performance (P<.05).

CONCLUSIONS

With US employers and purchasers having largely rejected traditional indemnity insurance as unaffordable, the results suggest that the current momentum toward open-model managed care plans is consistent with goals for high-quality primary care, but that the effects of specific financial and nonfinancial incentives used by plans must continue to be examined.

Reliability and validity of French, German, Italian, Dutch, and UK English translations of the Medical Outcomes Study HIV Health Survey

OBJECTIVES

Test the reliability and validity of 5 translations of the 34-item version of the MOS HIV for use in multinational clinical trials.

RESEARCH DESIGN

Investigators in five countries followed a standardized protocol and recruited HIV+ patients stratified by disease stage: asymptomatic; symptomatic; and AIDS. During routine clinic visits, patients completed the MOS HIV and a checklist of HIV-related symptoms. Clinicians reported patients' demographics, most recent CD4+ count and disease stage.

SUBJECTS

Three hundred and sixty three HIV+ outpatients attending AIDS clinics in The Netherlands, France, Germany, Italy, and England.

MEASURES

Dutch, French, German, Italian, and UK English translations of the MOS HIV CD4+ cell count and the SCL-57.

RESULTS

All translations recruited roughly equal proportions of each disease stage, although the number of patients recruited differed by translation (n: German = 92, French = 86; Italian = 88; UK English = 72; and Dutch = 25). Internal consistency reliability was similar across translations and adequate (alpha >.70) for all scales except for Mental Health in the French sample. Multi-trait analyses supported structural validity of the MOS HIV scales in each translation. Principal component analysis of scale scores identified 2 dimensions for all translations except German. For all translations, scores were significantly correlated with symptom severity scores but were uncorrelated with CD4+ cell counts.

CONCLUSIONS

In general, the 5 translations of the MOS HIV had similar psychometric properties to those reported in the validation study for the original US English version of the MOS HIV. With some revision, these translations promise to provide useful quality of life data from HIV+ subjects in clinical trials.

John E. Ware Jr. on health status and quality of life assessment and the next generation of outcomes measurement. Interview by Marcia Stevic and Katie Berry

John E. Ware Jr. PhD, is a founder of QualityMetric. Inc., as well as its president and chief scientific officer. He also is executive director of the Health Assessment Lab at the Health Institute, New England Medical Center, and holds professorships at Harward University and at Tufts University School of Medicine. For 14 years, he was senior research psychologist at RAND, where he developed health status and patient satisfaction measures used in the Health Insurance Experiment. He also was principal investigator for the Medical Outcomes Study (MOS), which developed the SF-36 Health Survey and other tools widely used in monitoring patient outcomes. A coauthor of papers from the MOS that received the Association for Health Services Research (AHSR) Article of the Year Award in 1993, Dr. Ware has received numerous awards for work in the field of outcomes research. He now is principal investigator of the International Quality of Life Assessment Project, which is translating and validating the SF-36 Health Survey for use in 45 countries. Dr. Ware also is developing the next generation of patient-based assessments that use advances in computer technology to provide very brief measures, yet meet the standard of precision necessary for use on an individual patient basis.

Health-related quality of life in chronic hepatitis C: impact of disease and treatment response. The Interventional Therapy Group

Hepatitis C infects nearly 4 million Americans. Most have chronic hepatitis C (CHC), which progresses to cirrhosis in about 20% of patients. Interferon treatment leads to transient responses in about 40% of patients and apparent eradication of infection in 7% to 40% of patients. In this report, we document the impact of CHC on health-related quality of life (HQL), and changes in HQL among treatment responders. Three hundred twenty-four CHC patients from 10 countries who had relapsed after responding to interferon-alfa therapy were randomized to monotherapy (IFN alfa-2b + placebo) or combination therapy (IFN alfa-2b + ribavirin), treated for 24 weeks, and followed up for 24 weeks. HQL was assessed using the Hepatitis Quality of Life Questionnaire (HQLQ), containing the generic SF-36 Health Survey, three additional generic scales, and two hepatitis-specific scales. Before treatment, CHC patients were impaired in 5 of 8 SF-36 concepts (physical functioning, role-physical, general health, vitality, and social functioning) in comparison with matched population norms. Sustained virological response (SVR) to treatment yielded improvements on three generic scales (vitality, social functioning, and health distress) and the CHC-specific health distress scale. Overall response to treatment (SVR plus histological improvement) yielded the same pattern of improvements with additional gains in generic general health and CHC-specific limitations. Successful treatment of CHC improved HQL as measured by both CHC-specific and generic measures of functional health and well being.

The SF-36 Arthritis-Specific Health Index (ASHI): II. Tests of validity in four clinical trials

OBJECTIVE

The SF-36 Arthritis-Specific Health Index (ASHI) was constructed to improve the responsiveness of the SF-36 Health Survey to changes in the severity of arthritis through the use of arthritis-specific scoring algorithms. This study compared the responsiveness of the ASHI and other generic scales and summary measures scored from the SF-36 in clinical trials of health outcomes for patients with arthritis.

METHODS

Longitudinal data for patients (n = 835) participating in four placebo-controlled trials were analyzed. Study participants had at least a 6-month history of moderate to severe osteoarthritis or rheumatoid arthritis of the knee or hip. All had undergone a washout period of 3 to 14 days before baseline assessment to bring about a flare state in osteoarthritis or rheumatoid arthritis symptoms. Their average age was 60 years, and 72% were female. Responders and nonresponders were classified on the basis of physician assessments of changes in arthritis severity, with blinding as to treatment group; treated and untreated (placebo) groups were also compared. For the SF-36 ASHI, generic physical (PCS) and mental (MCS) component summary measures and each of eight subscales scored from the SF-36 (acute version) change scores were computed by subtracting scores before treatment from scores at 2-week follow-up. To evaluate empirical validity, analyses of variance were performed. For each measure, an F-ratio was computed for the comparison between clinically defined groups of responders and nonresponders and between groups of patients assigned to placebo versus drug therapy. Relative validity (RV) coefficients were computed for the ASHI in comparison with PCS, MCS, and the best SF-36 scale to determine which was more responsive.

RESULTS

In analyses of each of the four trials and all trials combined, RV coefficients for the ASHI were higher than those for both of the generic SF-36 summary measures and for the most valid SF-36 scale (Bodily Pain), with only one exception. Across 40 tests of validity in distinguishing treated from untreated patients, the ASHI was 5% to 19% more valid than the best SF-36 scale (RV = 1.05-1.19; RV = 1.10 in all trials combined). The generic summary measures (PCS and MCS) were much less valid in these tests (RV = 0.67 and 0.27, respectively). In analyses of responders and nonresponders, RV coefficients for the ASHI ranged from 0.70 to 1.22 (RV = 1.04 in all trials combined), in comparison with the best SF-36 subscale, which was always Bodily Pain. RV coefficients were lower for PCS (RV = 0.75) and much lower than the MCS (RV = 0.18) in comparisons of treatment outcomes based on all trials combined.

CONCLUSION

The ASHI appears to be more valid than the eight SF-36 scales and PCS and MCS summary measures for purposes of distinguishing between treated and untreated patients and between clinical responders and nonresponders. This study demonstrates the feasibility of improving the validity of the SF-36 through the use of arthritis-specific scoring while retaining the option of generic scoring, which makes it possible to also compare results across diseases and treatments.

The SF-36 Health Survey as a generic outcome measure in clinical trials of patients with osteoarthritis and rheumatoid arthritis: relative validity of scales in relation to clinical measures of arthritis severity

OBJECTIVE

To evaluate the validity of SF-36 Health Survey (SF-36) scale scores and summary measure scores to describe the health burden of arthritis and to be responsive to clinical indicators of arthritis severity used in four clinical trials.

METHODS

Adults participating in four double-blinded, placebo-controlled clinical trials of therapy for osteoarthritis or rheumatoid arthritis were administered the SF-36 concurrent with clinical measures of disease severity (n = 1,016). Data were collected before treatment and 2 weeks after treatment. Mean SF-36 scores for all patients with arthritis at baseline were compared to a sociodemographically equivalent national norm to test the ability of the SF-36 to describe the burden of arthritis. To test the responsiveness of SF-36 scores to clinical measures of arthritis severity, mean SF-36 scale scores were compared across patients differing in arthritis severity before treatment. Two-week mean SF-36 change scores were compared across patients who improved in arthritis severity (responders) versus patients who did not improve (nonresponders). F-statistics and relative validity coefficients were computed to determine how well each SF-36 scale and summary measure discriminated among arthritis severity levels and distinguished treatment responders from nonresponders, relative to the best scale.

RESULTS

Large and statistically significant differences in mean SF-36 scale scores and summary measures were found such that trial participants scored in worse health than a sociodemographically equivalent US general population norm. In addition, the largest SF-36 scale scores were found to significantly differ across clinically defined levels of arthritis severity. Finally, it was found that the SF-36 scales that best discriminate among arthritis severity groups cross-sectionally were also best at discriminating treatment responders from nonresponders.

CONCLUSION

Results of this study support the validity of the SF-36 to document the health burden of arthritis and as a measure of generic health outcome for clinical trials of alternative treatments for osteoarthritis and rheumatoid arthritis patients.

The SF-36 Health Survey as a generic outcome measure in clinical trials of patients with osteoarthritis and rheumatoid arthritis: tests of data quality, scaling assumptions and score reliability

OBJECTIVE

To evaluate the psychometric assumptions underlying the construction and scoring of SF-36 scales and summary measures among clinical trial participants with arthritis.

METHODS

Cross-sectional SF-36 data from the baseline assessment of adult patients (n = 1,016) participating in four placebo-controlled clinical trials of treatment for arthritis were analyzed with blinding as to treatment. Tests of the completeness of data, scaling assumptions, internal-consistency reliability, and factor structure of SF-36 scales were performed for the combined sample. Eligible participants had at least a 6-month history of moderate to severe osteoarthritis or rheumatoid arthritis of the knee or hip. Participants meeting inclusion criteria had undergone a washout period of 3-14 days before baseline assessment to bring about a flare state in osteoarthritis or rheumatoid arthritis symptoms. Baseline sample sizes for the three osteoarthritis trials were n = 121, n = 341, and n = 187. The baseline sample size for the rheumatoid arthritis trial was n = 367. The average age of participants was 60 years, and the majority were females (72%). Measured were functional health and well-being scales and physical and mental health summary measures from the SF-36 Health Survey acute form.

RESULTS

Missing responses ranged from 0.0% to 1.5% across SF-36 items, and scale scores could be computed for 96.8% to 100% of participants across trials. In all four trials, item internal consistency tests were passed (91.4%-97.1%) and item discriminant validity tests were passed (96.9%-100.0%). Across the four trials, internal-consistency reliability coefficients ranged from a low of 0.75 to a high of 0.91 for the eight scales (median = 0.84), exceeding the minimum standards for group comparisons. Ceiling effects were minimal for most scales, and floor effects were noteworthy for the role physical and role emotional scales. Physical and mental health factors identified in previous studies were replicated.

CONCLUSION

The SF-36 Health Survey proved to be a psychometrically sound tool for the assessment of the health status of adult participants in clinical trials of arthritis.