Comparison of responses to SF-36 Health Survey questions with one-week and four-week recall periods

OBJECTIVE

To compare the measurement properties of acute (one-week recall) and standard (four-week recall) versions of SF-36 Health Survey (SF-36) scale scores.

DATA SOURCES

SF-36 data collected from 142 participants (60% female, average age 39) in a clinical trial of an asthma medication: 74 patients randomized to the acute form and 68 to the standard.

DATA COLLECTION

The SF-36 was self-administered at the time of a clinic visit (before clinical examination) to synchronize with clinical measures of disease severity at three different time points during the clinical trial: -2 weeks (two weeks before randomization to treatment), baseline (week 0 or randomization), and +4 weeks (four weeks after baseline).

PRINCIPAL FINDINGS

The acute form yielded high-quality data; scales conformed to the assumptions of the summated ratings method used to score the standard SF-36; and scales had good distributional properties, were reliable, and had a factor content similar to the standard. The data indicated that while the acute form was more sensitive than the standard to change in health status associated with changes in acute symptoms, acute scale scores may not be comparable to national norms based on the standard, particularly for those scales that assess frequency of health events during a specified time period.

CONCLUSIONS

Results support the use of the acute form in its intended applications; however, further research is required to document the generalizability of greater sensitivity of the acute form to recent changes in health and to explore whether norms based on the standard can be used to interpret the acute scale scores.

Asian-American patient ratings of physician primary care performance

OBJECTIVE

To examine how Asian-American patients' ratings of primary care performance differ from those of whites. Latinos, and African-Americans.

DESIGN

Retrospective analyses of data collected in a cross-sectional study using patient questionnaires.

SETTING

University hospital primary care group practice.

PARTICIPANTS

In phase 1, successive patients who visited the study site for appointments were asked to complete the survey. In phase 2, successive patients were selected who had most recently visited each physician, going back as far as necessary to obtain 20 patients for each physician. In total, 502 patients were surveyed, 5% of whom were Asian-American.

MAIN RESULTS

After adjusting for potential confounders, Asian-Americans rated overall satisfaction and 10 of 11 scales assessing primary care significantly lower than whites did. Dimensions of primary care that were assessed include access, comprehensiveness of care, integration, continuity, clinical quality, interpersonal treatment, and trust. There were no differences for the scale of longitudinal continuity. On average, the rating scale scores of Asian-Americans were 12 points lower than those of whites (on 100-point scales).

CONCLUSIONS

We conclude that Asian-American patients rate physicians primary care performance lower than do whites, African-Americans, and Latinos. Future research needs to focus on Asian-Americans to determine the generalizability of these findings and the extent to which they reflect differences in survey response tendencies or actual quality differences.

Evaluation of the MOS SF-36 Physical Functioning Scale (PF-10): II. Comparison of relative precision using Likert and Rasch scoring methods

This study examined the relative precision (RP) of two methods of scoring the 10-item Physical Functioning Scale (PF-10) from a large sample of patients (n = 3445) of the Medical Outcomes Study. Based on a Likert scaling model, the PF-10 summated scoring method was compared with a Rasch Item Response Theory (IRT) scaling model in which raw scores were transformed into a latent trait variable of physical functioning. Potential differences between scoring methods were hypothesized to be attributed to: (1) the logarithmic nature of the Rasch transformation; (2) the unevenness of the PF-10 item distributions; and (3) reduction of within-group variance. RP ratios favored the Rasch model in discriminating between patients who differed in disease severity. The Rasch and Likert scoring models performed similarly for tests involving sensitivity to change over a two-year follow-up period. In all comparisons, differences between methods were most apparent in clinical groups whose scores most approximated the extremes of the score distribution. Further research is necessary to test for differences between scoring models in discrimination and sensitivity to change among clinical groups whose scores are sufficiently spread across the continuum of physical functioning, in particular patients with either very high or low physical functioning. The Rasch model of scoring may have important implications for the clinical interpretation of individual scores at all ranges of the scale.

Health-related quality of life among patients with metastatic prostate cancer

OBJECTIVES

To assess and compare the quality of life of men with advanced prostate cancer who are in remission receiving treatment with a luteinizing hormone-releasing hormone (LHRH) agonist and flutamide or who are in progression.

METHODS

We conducted a cross-sectional survey to measure health-related quality of life in a cohort of 113 patients with metastatic prostate cancer, 60 in remission and 53 with disease progression, using a battery of questionnaires, including the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire-C30, the Medical Outcomes Study Short Form Health Survey SF-36, and a prostate cancer-specific module.

RESULTS

Patients in remission receiving an LHRH agonist and flutamide reported a significantly better quality of life compared with patients with disease progression (P < 0.011). Men with hormone-sensitive cancer had significantly less bodily pain, more vitality, more social interactions, and better mental health than patients with hormone-resistant disease. No differences were noted between the two groups concerning treatment-related problems such as diarrhea, constipation, urinary symptoms, sexual function, sexual satisfaction or hot flashes, although men in remission tended to rate each of these items more favorably than did men with disease progression. Men in remission have a health-related quality of life that is similar to an equivalent norm for men in the United States general population as compared with men with disease progression, who demonstrate significant compromise in all domains measured.

CONCLUSIONS

Patients in remission receiving an LHRH agonist and flutamide have a quality of life that is indistinguishable from a matched male population without prostate cancer and a quality of life significantly better than that of men with androgen-resistant disease. Among patients who respond to total androgen ablation, flutamide and an LHRH agonist provide significant, measurable benefits to recipients independent of any possible improvement in longevity.

Differences in 4-year health outcomes for elderly and poor, chronically ill patients treated in HMO and fee-for-service systems. Results from the Medical Outcomes Study

OBJECTIVE

To compare physical and mental health outcomes of chronically ill adults, including elderly and poor subgroups, treated in health maintenance organization (HMO) and fee-for-service (FFS) systems.

STUDY DESIGN

A 4-year observational study of 2235 patients (18 to 97 years of age) with hypertension, non-insulin-dependent diabetes mellitus (NIDDM), recent acute myocardial infarction, congestive heart failure, and depressive disorder sampled from HMO and FFS systems in 1986 and followed up through 1990. Those aged 65 years and older covered under Medicare and low-income patients (200% of poverty) were analyzed separately.

SETTING AND PARTICIPANTS

Offices of physicians practicing family medicine, internal medicine, endocrinology, cardiology, and psychiatry, in HMO and FFS systems of care. Types of practices included both prepaid group (72% of patients) and independent practice association (28%) types of HMOs, large multispecialty groups, and solo or small, single-specialty practices in Boston, Mass, Chicago, Ill, and Los Angeles, Calif.

OUTCOME MEASURES

Differences between initial and 4-year follow-up scores of summary physical and mental health scales from the Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36) for all patients and practice settings.

RESULTS

On average, physical health declined and mental health remained stable during the 4-year follow-up period, with physical declines larger for the elderly than for the nonelderly (P<.001). In comparisons between HMO and FFS systems, physical and mental health outcomes did not differ for the average patient; however, they did differ for subgroups of the population differing in age and poverty status. For elderly patients (those aged 65 years and older) treated under Medicare, declines in physical health were more common in HMOs than in FFS plans (54% vs 28%; P<.001). In 1 site, mental health outcomes were better (P<.05) for elderly patients in HMOs relative to FFS but not in 2 other sites. For patients differing in poverty status, opposite patterns of physical health (P<.05) and for mental health (P<.001) outcomes were observed across systems; outcomes favored FFS over HMOs for the poverty group and favored HMOs over FFS for the nonpoverty group.

CONCLUSIONS

During the study period, elderly and poor chronically ill patients had worse physical health outcomes in HMOs than in FFS systems; mental health outcomes varied by study site and patient characteristics. Current health care plans should carefully monitor the health outcomes of these vulnerable subgroups.

Health status in patients with chronic fatigue syndrome and in general population and disease comparison groups

PURPOSE

To measure the functional status and well-being of patients with chronic fatigue syndrome (CFS), and compare them with those of a general population group and six disease comparison groups.

PATIENTS AND METHODS

The subjects of the study were patients with CFS (n = 223) from a CFS clinic, a population-based control sample (n = 2,474), and disease comparison groups with hypertension (n = 2,089), congestive heart failure (n = 216), type II diabetes mellitus (n = 163), acute myocardial infarction (n = 107), multiple sclerosis (n = 25), and depression (n = 502). We measured functional status and well-being using the Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36), which is a self-administered questionnaire in which lower scores are indicative of greater impairment.

RESULTS

Patients with CFS had far lower mean scores than the general population control subjects on all eight SF-36 scales. They also scored significantly lower than patients in all the disease comparison groups other than depression on virtually all the scales. When compared with patients with depression, they scored significantly lower on all the scales except for scales measuring mental health and role disability due to emotional problems, on which they scored significantly higher. The two SF-36 scales reflecting mental health were not correlated with any of the symptoms of CFS except for irritability and depression.

CONCLUSION

Patients with CFS had marked impairment, in comparison with the general population and disease comparison groups. Moreover, the degree and pattern of impairment was different from that seen in patients with depression.

Improvement of quality of life by treatment with cetirizine in patients with perennial allergic rhinitis as determined by a French version of the SF-36 questionnaire

BACKGROUND AND AIM

Perennial allergic rhinitis impairs social life, but it is not known whether quality of life may be improved when patients are treated with an H1-blocker. A randomized, double-blind, placebo-controlled study was carried out with cetirizine to assess the effect of this drug on quality of life.

METHODS

Two hundred seventy-four patients with perennial allergic rhinitis were tested. Quality of life was measured by using the Medical Outcome Study Short-Form Health Survey (SF-36) questionnaire. After a 2-week run-in period, cetirizine, 10 mg once daily, (136 patients) or placebo (138 patients) was given for the next 6 weeks. The SF-36 questionnaire was administered after the run-in period (at the start of treatment) and after 1 and 6 weeks of treatment. Symptom-medication scores were measured daily during the study.

RESULTS

After the run-in period (baseline), there were no significant differences between the cetirizine and placebo groups in terms of symptoms or quality-of-life scores. After 6 weeks of treatment, percentage of days without rhinitis or with only mild rhinitis symptoms was significantly greater in the cetirizine group in comparison with the placebo group (p < 0.0001, Mann-Whitney U test). All of the nine quality-of-life dimensions were significantly improved (from p = 0.01 to p < 0.0001, Mann-Whitney U test) after 1 and 6 weeks of cetirizine treatment compared with placebo. There was no improvement in the placebo group.

CONCLUSIONS

This study is the first to demonstrate that an H1-blocker, cetirizine, can improve quality of life for patients with perennial allergic rhinitis.

The effects of recombinant human erythropoietin on functional health and well-being in chronic dialysis patients

As a component of the open-label, multicenter National Cooperative Recombinant Human Erythropoietin (Epo) Study, the health-related quality-of-life effects of Epo therapy were assessed in 484 dialysis patients who had not previously been treated with Epo therapy (New-to-Epo) and 520 dialysis patients who were already receiving Epo therapy at the time of study enrollment (Old-to-Epo). Using scales from the Medical Outcomes Study 36-item Short Form Health Survey (SF-36), health-related quality of life was assessed on study enrollment (baseline) and at an average of 99 days follow-up. At baseline, SF-36 scores for Old- and New-to-Epo patients were well below those observed in the general population, reflecting substantial impairments in functional status and well-being among patients with chronic renal failure. Significant improvements from baseline to follow-up were observed among New-to-Epo patients in vitality, physical functioning, social functioning, mental health, looking after the home, social life, hobbies, and satisfaction with sexual activity (P < 0.05 for each). The mean improvements in hematocrit values among New-to-Epo and Old-to Epo patients were 4.6 and 0.3, respectively. At the time of follow-up, SF-36 scores for New-to-Epo patients were comparable with those observed among Old-to-Epo patients, whose scores did not change significantly from baseline to follow-up. Analysis of the relationship between Epo therapy, hematocrit values, and health-related quality of life suggest that some of the beneficial quality-of-life effects of Epo are mediated through a change in hematocrit level.

Characteristics of physicians with participatory decision-making styles

OBJECTIVES

To identify physician and practice characteristics associated with a physician's propensity to involve patients in diagnostic and treatment decisions, or participatory decision-making style.

DESIGN

A representative cross-sectional sample of patients participating in the Medical Outcomes Study characterized each physician's style by using a self-reported questionnaire. A single averaged style score was generated for each physician. Style scores were compared among physicians who differed in age, sex, minority status, specialty, primary care training or training in interviewing skills, satisfaction with professional autonomy, and practice volume.

SETTINGS

Solo practices, multispecialty groups, and health maintenance organizations in Boston, Chicago, and Los Angeles.

PARTICIPANTS

7730 patients sampled over 9 days from the practices of 300 physicians. Physicians were practicing general internal medicine, family medicine, cardiology, and endocrinology.

MEASUREMENTS

Participatory decision-making style was measured using a three-item scale on a questionnaire that was completed by patients after their office visit. Physician and practice characteristics were reported by physicians on self-administered questionnaires.

RESULTS

Among patients of physicians who were rated in the lowest (least participatory) quartile, one third changed physicians in the following year; among patients of physicians who were rated in the highest quartile, only 15% changed physicians. Higher scores were associated with greater patient satisfaction. Physicians who had had primary care training or training in interviewing skills scored higher than those without such training. Physicians in higher-volume practices were rated as less participatory than those in lower-volume practices. Physicians who were satisfied with their level of professional autonomy were rates as more participatory than those who were dissatisfied.

CONCLUSION

Participatory decision-making style is influenced by physicians' background, training, practice volume, and professional autonomy. Because participatory decision-making style is related to patient satisfaction and loyalty to the physician, cost-containment strategies that reduce time with patients and decrease physician autonomy may result in suboptimal patient outcomes.

The Swedish SF-36 Health Survey--I. Evaluation of data quality, scaling assumptions, reliability and construct validity across general populations in Sweden

We document the applicability of the SF-36 Health Survey, which was translated into Swedish using methods later adopted by the International Quality of Life Assessment (IQOLA) Project procedures. To test its appropriateness for use in Sweden, it was administered through mail-out/mail-back questionnaires in seven general population studies with an average response rate of 68%. The 8930 respondents varied by gender (48.2% men), age (range 15-93 years, mean age 42.7), marital status, education, socio-economic status, and geographical area. Psychometric methods used in the evaluation of the SF-36 in the U.S. were replicated. Over 90% of respondents had complete items for each of the eight SF-36 scales, although more missing data were observed for subjects 75 years and over. Scale scores could be computed for the vast majority of respondents (95% and over); slightly fewer in the oldest subgroup. Item-internal consistency was consistently high across socio-demographic subgroups and the eight scales. Most reliability estimates exceeded the 0.80 level. The highest reliability was observed for the Bodily Pain Scale where all subgroups met the 0.90 level recommended for individual comparisons; coefficients at or above 0.90 were also observed in most subgroups for the Physical Functioning Scale. Tests of scaling assumptions including hypothesized item groupings, which reflect the construct validity of scales, were consistently favorable across subgroups, although lower rates were noted in the oldest age group. In conclusion, these studies have yielded empirical evidence supporting the feasibility of a non-English language reproduction of the SF-36 Health Survey. The Swedish SF-36 is ready for further evaluation.

Usefulness of the SF-36 Health Survey in measuring health outcomes in the depressed elderly

Longitudinal data from a clinical trial were analyzed to evaluate the usefulness of the SF-36 Health Survey in estimating the impact of depression and changes in severity over time on the functional health and well-being of 532 patients, 60 to 86 years of age, who met DSM-III-R criteria for major depressive disorder. The Hamilton Depression Rating Scale, the Clinician's Global Impression of Severity and Improvement, and the Geriatric Depression Scale were used to define clinical severity and changes in severity over a 6-week period. Answers to SF-36 questions tended to be complete and to satisfy assumptions underlying methods of scale construction and scoring. As hypothesized, the SF-36 Mental Health Scale and Mental Component Summary measure, shown in previous studies to be most valid in measuring differences in mental health, exhibited the strongest associations with severity of depression in cross-sectional analyses and were most responsive to changes in severity in longitudinal comparisons. We conclude that the SF-36 Health Survey is useful for estimating the burden of depression and in monitoring changes in functional health and well-being over time among the depressed elderly.

Patient and visit characteristics related to physicians' participatory decision-making style. Results from the Medical Outcomes Study

This article identifies the characteristics of patients and office visits associated with decreased mutual decision-making between physicians and patients. In the baseline cross-sectional survey of the Medical Outcomes Study we measured specific patient characteristics hypothesized to influence participatory decision-making (PDM) styles of physicians. We related these characteristics to the PDM style scores for their physicians. The study was conducted in solo practices, multi-specialty groups, and health maintenance organizations in Boston, Chicago, and Los Angeles. Over a 9-day period in 1986, 8,316 patients were sampled from the practices of 344 participating Medical Outcome Study physicians, representing general internal medicine, family practice, cardiology and endocrinology. Physicians' PDM style was measured using a 3-item scale included on the baseline questionnaire completed by patients after office visits to their Medical Outcome Study physicians. We found that the elderly (age 75 and older) and young adult (younger than age 30) patients, patients with high school education or less, minority patients, and male patients had the least participatory visits with their physicians. We also found that male patients seeing male physicians had the least participatory visits compared with male patients seeing female physicians, and compared with female patients seeing physicians of either gender. Our data indicated that PDM style increased as duration or tenure of the physician-patient relationship increased. Participatory decision-making style also increased with increasing length of office visits. The role of effective interpersonal care in optimizing patients' health outcomes may be underappreciated. We have identified seven patient and visit characteristics that maximize or compromise the effectiveness of interpersonal care. Recognizing those at risk for suboptimal interpersonal care may be a first step in improving the management of chronic disease. Key words: participatory decision-making style; interpersonal care; doctor-patient communication.

The Swedish SF-36 Health Survey--I. Evaluation of data quality, scaling assumptions, reliability and construct validity across general populations in Sweden

We document the applicability of the SF-36 Health Survey, which was translated into Swedish using methods later adopted by the International Quality of Life Assessment (IQOLA) Project procedures. To test its appropriateness for use in Sweden, it was administered through mail-out/mail-back questionnaires in seven general population studies with an average response rate of 68%. The 8930 respondents varied by gender (48.2% men), age (range 15-93 years, mean age 42.7), marital status, education, socio-economic status, and geographical area. Psychometric methods used in the evaluation of the SF-36 in the U.S. were replicated. Over 90% of respondents had complete items for each of the eight SF-36 scales, although more missing data were observed for subjects 75 years and over. Scale scores could be computed for the vast majority of respondents (95% and over); slightly fewer in the oldest subgroup. Item-internal consistency was consistently high across socio-demographic subgroups and the eight scales. Most reliability estimates exceeded the 0.80 level. The highest reliability was observed for the Bodily Pain Scale where all subgroups met the 0.90 level recommended for individual comparisons; coefficients at or above 0.90 were also observed in most subgroups for the Physical Functioning Scale. Tests of scaling assumptions including hypothesized item groupings, which reflect the construct validity of scales, were consistently favorable across subgroups, although lower rates were noted in the oldest age group. In conclusion, these studies have yielded empirical evidence supporting the feasibility of a non-English language reproduction of the SF-36 Health Survey. The Swedish SF-36 is ready for further evaluation.

Base-line quality-of-life assessment in the National Surgical Adjuvant Breast and Bowel Project Breast Cancer Prevention Trial

BACKGROUND

The Breast Cancer Prevention Trial (BCPT) is a large, multicenter chemoprevention trial testing the efficacy of the antiestrogen drug tamoxifen for prevention of breast cancer and coronary heart disease in healthy women at high risk of breast cancer. The BCPT evolved from a series of prior studies in early stage breast cancer demonstrating the efficacy of tamoxifen in the prevention of systemic breast cancer recurrence and in the reduction of contralateral breast cancers.

PURPOSE

The purpose of this article is to describe the methodologic considerations in the collection of health-related quality-of-life (HRQL) data in the BCPT and to present base-line HRQL data on the first 9749 participants.

METHODS

An HRQL questionnaire that included the Center for Epidemiologic Studies-Depression Scale, a symptom checklist, the Medical Outcomes Study 36-item short form (MOS-SF-36), and the MOS sexual problems questions was completed by participants in the BCPT at base line (prior to random assignment). Medical and demographic information, as well as projected risk of breast cancer, were collected as part of study eligibility. Descriptive and correlational data were examined for these study participants.

RESULTS

BCPT participants report high levels of functioning compared with U.S. general population norms but still report an average of 8.9 distinct symptoms during the past 4 weeks. Depression is less prevalent among the participants than in community samples, which reflects the exclusion of clinically depressed individuals. Sixty-five percent reported being sexually active in the past 6 months, with an age-related decline in sexual activity. Younger women reported fewer sexual problems than older women. There is a strong correlation between the two mental health measures, moderate to weak correlations between HRQL scales and levels of self-reported symptoms, and only weak correlations between measures of breast cancer risk and HRQL scales. The MOS-SF-36 scores were examined for three consecutive recruitment samples (0-6 months, 7-12 months, and 13-20 months), and the base-line scores were slightly better for the earliest group of participants.

CONCLUSIONS

This article demonstrates the feasibility of collecting HRQL data in a large, multicenter, chemoprevention trial for women at high risk of breast cancer. The successful integration of HRQL data collection into this clinical trial attests to its value as a safety-monitoring end point and as an explicit and measurable outcome for the entire trial.

IMPLICATIONS

HRQL data are important for studies in which healthy populations are involved and in which the potential for decrements in quality of life are real or perceived.

The status of health assessment 1994

General health status and a broader concept of quality of life are discussed and methods of widely used surveys are reviewed. A consensus regarding the inclusion of measures of physical, mental, social, and role functioning and general health perceptions is noted for comprehensive assessments of health. A schematic of relationships among condition-specific and generic measures is presented along with results expected for objective and subjective measures of physical and mental dimensions of health. Suggestions are offered for the labeling of disease-specific and generic measures and ways to avoid confounding of content. Applications of health surveys in general population monitoring, health policy evaluation, clinical trials of alternative treatments, monitoring and improving of health care outcomes, and in everyday clinical practice are exemplified and discussed. A unified measurement strategy is proposed and arguments in favor of standardizing the content of health surveys across applications are offered.

Comparison of methods for the scoring and statistical analysis of SF-36 health profile and summary measures: summary of results from the Medical Outcomes Study

Physical component summary (PCS) and mental component summary (MCS) measures make it possible to reduce the number of statistical comparisons and thereby the role of chance in testing hypotheses about health outcomes. To test their usefulness relative to a profile of eight scores, results were compared across 16 tests involving patients (N = 1,440) participating in the Medical Outcomes Study. Comparisons were made between groups known to differ at a point in time or to change over time in terms of age, diagnosis, severity of disease, comorbid conditions, acute symptoms, self-reported changes in health, and recovery from clinical depression. The relative validity (RV) of each measure was estimated by a comparison of statistical results with those for the best scales in the same tests. Differences in RV among scales from the Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36) were consistent with those in previous studies. One or both of the summary measures were significant for 14 of 15 differences detected in multivariate analyses of profiles and detected differences missed by the profile in one test. Relative validity coefficients ranged from .20 to .94 (median, .79) for PCS in tests involving physical criteria and from .93 to 1.45 (median, 1.02) for MCS in tests involving mental criteria. The MCS was superior to the best SF-36 scale in three of four tests involving mental health. Results suggest that the two summary measures may be useful in most studies and that their empiric validity, relative to the best SF-36 scale, will depend on the application. Surveys offering the option of analyzing both a profile and psychometrically based summary measures have an advantage over those that do not.

Advances in methods for assessing the impact of epilepsy and antiepileptic drug therapy on patients' health-related quality of life

We studied 31 previously validated and newly developed generic and epilepsy-specific scales to evaluate their usefulness for assessing the impact of epilepsy and anti-epileptic drug (AED) therapy on health-related quality of life (HRQOL). Included were the MOS SF-36 Health Survey, additional measures of mental health, cognition, epilepsy-specific perception of control, behavioural problems, distress, worries and experiences, the Liverpool Epilepsy Impact and Seizure Severity scales, and a patient-completed symptom checklist. Questionnaires were completed twice by 136 patients on AED therapy in a multicentre study in the UK. Validity was assessed in relation to disease severity, defined as time since last seizure, and to patient-reported symptoms. Statistical analyses to estimate the contribution of HRQOL information of each scale relative to that of others were conducted. The 171-item questionnaire could be completed by out-patients with epilepsy with good data quality. With few exceptions, generic and epilepsy-specific measures satisfied psychometric tests of hypothesized item groupings and scale score reliability (internal consistency and test-retest reliability) and differentiated well between groups of patients differing in time since last seizure and in symptom impact, regardless of time since last seizure. However, scales differed widely in their validity in discriminating between groups of patients known to differ clinically. The SF-36 Role Physical scale best discriminated among groups differing in disease severity. The epilepsy-specific Mastery, Impact, Experience, Worry, Distress, and Agitation scales were among the 10 best measures in discriminating among groups differing in disease severity. Generic measures, especially measures of social and role functioning and mental health, were best at differentiating groups of patients differing in symptom impact. Recommendations are offered for concepts and specific scales most likely to be useful in future studies of the HRQOL burden of epilepsy and the HRQOL benefits of AED therapy.

Construction and validation of an alternate form general mental health scale for the Medical Outcomes Study Short-Form 36-Item Health Survey

Alternate-form health measures are useful for clinical trials or health services research requiring repeated administrations over a short interval of time. Further, by using alternate-form methodology, they can be utilized to estimate score reliability. Data from the Medical Outcomes Study were used to evaluate five alternate forms of the Short-Form 36-Item Health Survey (SF-36) general mental health scale (MHI-5). Well-established psychometric criteria were used to select the best alternate form and to estimate the reliability of the MHI-5 using the alternate-form methodology. Although a considerable degree of comparability across the five alternate forms was observed for criteria pertaining to estimates of item-internal consistency and reliability, distributional characteristics of scales, tests of empirical validity, and score equivalence at the individual level, we recommend one alternate form that satisfied all evaluation criteria and did so better than any other alternate form. Using the alternate-form methodology of estimating reliability, results suggest that the internal-consistency method underestimates the reliability of the MHI-5 by 3%. The methodology presented here should prove useful to others interested in constructing and evaluating alternate forms, and the alternate form recommended here (MHI-5AF) should prove useful across many health status assessment applications.

Evaluating translations of health status questionnaires. Methods from the IQOLA project. International Quality of Life Assessment

There is growing demand for translations of health status questionnaires for use in multinational drug therapy studies and for population comparisons of health statistics. The International Quality of Life Assessment (IQOLA) Project is conducting a three-stage research program to determine the feasibility of translating the SF-36 Health Survey, widely used in English-speaking countries, into other languages. In stage 1, the conceptual equivalence and acceptability of translated questionnaires are evaluated and improved using qualitative and quantitative methods. In stage 2, assumptions underlying the construction and scoring of questionnaire scales are tested empirically. In stage 3, the equivalence of the interpretation of questionnaire scores across countries is tested using methods that closely approximate their intended use, and empirical results are compared. Data analyses from Sweden and the United Kingdom, as well as other research cited, support the feasibility of cross-cultural health measurement using the SF-36.

Comparisons of the costs and quality of norms for the SF-36 health survey collected by mail versus telephone interview: results from a national survey

Many health status surveys have been designed for mail, telephone, or in-person administration. However, with rare exception, investigators have not studied the effect the survey mode of administration has on the way respondents assess their health and other important parameters (such as response rates, nonresponse bias, and data quality), which can affect the generalizability of results. Using a national sampling frame of noninstitutionalized adults from the General Social Survey, we randomly assigned adults to a mail survey (80%) or a computer-assisted telephone survey (20%). The surveys were designed to provide national norms for the SF-36 Health Survey. Total data collection costs per case for the telephone survey ($47.86) were 77% higher than that for the mail survey ($27.07). A significantly higher response rate was achieved among respondents randomly assigned to the mail (79.2%) than telephone survey (68.9%). Nonresponse bias was evident in both modes but, with the exception of age, was not differential between modes. The rate of missing responses was higher for mail than telephone respondents (1.59 vs. 0.49 missing items). Health ratings based on the SF-36 scales were less favorable, and reports of chronic conditions were more frequent, for mail than telephone respondents. Results are discussed in light of the trade-offs involved in choosing a survey methodology for health status assessment applications. Norms for mail and telephone versions of the SF-36 survey are provided for use in interpreting individual and group scores.

Evaluation of the MOS SF-36 physical functioning scale (PF-10): I. Unidimensionality and reproducibility of the Rasch item scale

Indexes developed to measure physical functioning as an essential component of general health status are often based on sets of hierarchically-structured items intended to represent a broad underlying concept. Rasch Item Response Theory (IRT) provides a methodology to examine the hierarchical structure, unidimensionality, and reproducibility of item positions (calibrations) along a scale. Data gathered on the 10-item Physical Functioning Scale (PF-10) from a large sample of Medical Outcomes Study patients (N = 3445) were used to examine the hierarchical order, unidimensionality, and reproducibility of item calibrations. Rasch-IRT analyses generated an empirical item hierarchy, confirmed the unidimensionality of the PF-10 for most patients, and established the reproducibility of item calibrations across patient populations and repeated tests. These findings support the content validity of the PF-10 as a measure of physical functioning and suggest that valid Rasch-IRT summary scores could be generated as an alternative to the current Likert summative scores. Unidimensionality and reproducibility of the item scale are essential prerequisites for the development of Rasch-based person measures of physical functioning that can be used across populations and over repeated tests.

Measuring the functional status and well-being of patients with migraine headache

OBJECTIVE

Compare adult migraineurs' health related quality of life to adults in the general U.S. population reporting no chronic conditions, and to samples of patients with other chronic conditions.

METHODS

Subjects (n = 845) were surveyed 2-6 months after participation in a placebo-controlled clinical trial and asked to complete a questionnaire including the SF-36 Health Survey, a migraine severity measurement scale and demographics. Results were adjusted for severity of illness and comorbidities. Scores were compared with responses to the same survey by the U.S. sample and by patients with other chronic conditions.

RESULTS

Response rate was 67%. After adjustment for comorbid conditions, SF-36 scale scores were significantly (P 0.001) lower in migraineurs, relative to age and sex-adjusted norms for the U.S. sample with no chronic conditions. Some health dimensions were more affected by migraine than other chronic conditions, while other dimensions were less affected by migraine. Measures of bodily pain, role disability due to physical health and social functioning discriminated best between migraineurs, the U.S. sample, and patients with other chronic conditions. Patients reporting moderate, severe and very severe migraines scored significantly (P < or = 0.001) lower on five of the eight SF-36 scales than the U.S. sample.

CONCLUSIONS

Migraine has a unique, significant quality of life burden.