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.

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 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.

Evaluation of a preliminary physical function item bank supported the expected advantages of the Patient-Reported Outcomes Measurement Information System (PROMIS).

OBJECTIVE: The Patient-Reported Outcomes Measurement Information System (PROMIS) was initiated to improve precision, reduce respondent burden, and enhance the comparability of health outcomes measures. We used item response theory (IRT) to construct and evaluate a preliminary item bank for physical function assuming four subdomains. STUDY DESIGN AND SETTING: Data from seven samples (N=17,726) using 136 items from nine questionnaires were evaluated. A generalized partial credit model was used to estimate item parameters, which were normed to a mean of 50 (SD=10) in the US population. Item bank properties were evaluated through Computerized Adaptive Test (CAT) simulations. RESULTS: IRT requirements were fulfilled by 70 items covering activities of daily living, lower extremity, and central body functions. The original item context partly affected parameter stability. Items on upper body function, and need for aid or devices did not fit the IRT model. In simulations, a 10-item CAT eliminated floor and decreased ceiling effects, achieving a small standard error (< 2.2) across scores from 20 to 50 (reliability >0.95 for a representative US sample). This precision was not achieved over a similar range by any comparable fixed length item sets. CONCLUSION: The methods of the PROMIS project are likely to substantially improve measures of physical function and to increase the efficiency of their administration using CAT.

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.

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.

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.

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.

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.

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.