A questionnaire to assess the generic and disease-specific health outcomes of patients with chronic hepatitis C

A 69-item questionnaire measuring generic functioning and well-being and disease-specific health outcomes was developed and tested using the pre-treatment data from patients with chronic hepatitis C (CHC) participating in two randomized trials of interferon -2b (n = 157). The questionnaire included all eight scales from the SF-36 and measures of nine other generic and disease-specific health concepts. Psychometric tests confirmed the assumptions underlying the construction and scoring of all generic and disease-specific scales. Cross-sectional tests of known groups validity showed that CHC patients scored worse on the generic scales than patients with other chronic conditions and worse than a healthy general population. The generic and disease-specific scale scores were lower in the presence of physical findings of CHC, as hypothesized, but only the physical functioning and bodily pain scales were linked to cirrhosis or extreme alanine aminotransferase (ALT) ratios. This instrument will be useful in studies of health outcome among patients with CHC, a condition whose health burden appears to have been underestimated in studies to date.     

A Kiswahili version of the SF-36 Health Survey for use in Tanzania: translation and tests of scaling assumptions

The objective of the study was to translate and adapt the SF-36 Health Survey for use in Tanzania and to test the psychometric properties of the Kiswahili SF-36. A cross-sectional study was conducted as part of a household survey of a representative sample of the adult population of Dar es Salaam, Tanzania. The IQOLA method of forward and backward translation was used to translate the SF-36 into Kiswahili. The translated questionnaire was administered by trained interviewers to 3,802 adults (50% women, mean (SD) age 31 (13) years, 50% married and 60% with primary education). Data quality and psychometric assumptions underlying the scoring of the eight SF-36 scales were evaluated for the entire sample and separately for the least educated subgroup (n=402), using multitrait scaling analysis. Forward and backward translation procedures resulted in a Kiswahili SF-36 that was considered conceptually equivalent to the US English SF-36. Data quality was excellent: only 1.2% of respondents were excluded because they answered less than half of the items for one or more scales; ninety percent of respondents answered mutually exclusive items consistently. Median item–scale correlations across the eight scales ranged from 0.47 to 0.81 for the entire sample. Median scaling success rates were 100% (range 87.5–100.0). The median internal consistency reliability of the eight scales for the entire sample was 0.81 (range 0.70–0.92). Floor effects were low and ceiling effects were high on five of the eight scales. Results for n=402 people without formal education did not differ substantially from those of the entire sample. The results of data quality and psychometric tests support the scoring of the eight scales using standard scoring algorithms. The Kiswahili translation of the SF-36 may be useful in estimating the health of people in Dar es Salaam. Evidence for the validity of the SF-36 for use in Tanzania needs to be accumulated.     

The Short Form Health Survey (SF-36): Translation and validation study of the Iranian version

This was a large population-based study to develop and validate the Iranian version of the Short Form Health Survey (SF-36) for use in health related quality of life assessment in Iran. A culturally comparable questionnaire was developed and pilot tested. Then, the Iranian version of the SF-36 was administered to a random sample of 4163 healthy individuals aged 15 years and over in Tehran. The mean age of the respondents was 35.1 (SD=16.0) years, 52% were female, mostly married (58%) and the mean years of their formal education was 10.0 (SD=4.5). Reliability was estimated using the internal consistency and validity was assessed using known groups comparison and convergent validity. In addition factor analysis was performed. The internal consistency (to test reliability) showed that all eight SF-36 scales met the minimum reliability standard, the Cronbachs coefficients ranging from 0.77 to 0.90 with the exception of the vitality scale (=0.65). Known groups comparison showed that in all scales the SF-36 discriminated between men and women, and old and the young respondents as anticipated (all p values less than 0.05). Convergent validity (to test scaling assumptions) using each item correlation with its hypothesized scale showed satisfactory results (all correlation above 0.40 ranging from 0.58 to 0.95). Factor analysis identified two principal components that jointly accounted for 65.9% of the variance. In general, the Iranian version of the SF-36 performed well and the findings suggest that it is a reliable and valid measure of health related quality of life among the general population.     

Difference in method of administration did not significantly impact item response: an IRT-based analysis from the Patient-Reported Outcomes Measurement Information System (PROMIS) initiative

Purpose

To test the impact of method of administration (MOA) on the measurement characteristics of items developed in the Patient-Reported Outcomes Measurement Information System (PROMIS).

Methods

Two non-overlapping parallel 8-item forms from each of three PROMIS domains (physical function, fatigue, and depression) were completed by 923 adults (age 18–89) with chronic obstructive pulmonary disease, depression, or rheumatoid arthritis. In a randomized cross-over design, subjects answered one form by interactive voice response (IVR) technology, paper questionnaire (PQ), personal digital assistant (PDA), or personal computer (PC) on the Internet, and a second form by PC, in the same administration. Structural invariance, equivalence of item responses, and measurement precision were evaluated using confirmatory factor analysis and item response theory methods.

Results

Multigroup confirmatory factor analysis supported equivalence of factor structure across MOA. Analyses by item response theory found no differences in item location parameters and strongly supported the equivalence of scores across MOA.

Conclusions

We found no statistically or clinically significant differences in score levels in IVR, PQ, or PDA administration as compared to PC. Availability of large item response theory-calibrated PROMIS item banks allowed for innovations in study design and analysis.     

Psychometric evaluation of the SF-36 health survey in Medicare managed care

Data quality and scoring assumptions for the SF-36 Health Survey were evaluated among the elderly and disabled, using 1998 Cohort I baseline Medicare HOS data (n=177,714). Missing data rates were low, and scoring assumptions were met. Internal consistency reliability was 0.83 to 0.93 for the eight scales and 0.94 and 0.89, respectively, for the physical (PCS) and mental (MCS) component summary measures. Results declined with increased risk factors (e.g., older age, more chronic conditions), but were well above accepted standards for all subgroups. These findings support using standard algorithms for scoring the SF-36 in the HOS and subgroup analyses of HOS data.     

Validation of the Kiswahili version of the SF-36 Health Survey in a representative sample of an urban population in Tanzania

The objective of this study was to assess the validity of a Kiswahili translation of the SF-36 Health Survey (SF-36) among an urban population in Tanzania, using the method of known-groups validation. People were randomly selected from a demographic surveillance system in Dar es Salaam. The representative sample consisted of 3,802 adults (15 years and older). Health status differences were hypothesized among groups, who differed in sex, age, socio-economic status and self-reported morbidity. Mean SF-36 scale scores were calculated and compared using t-test and ANOVA. Women had significantly lower mean SF-36 scale scores (indicating worse health status) than men on all scales and scores were lower for older people than younger on all domains, as hypothesized. On five of the eight SF-36 scales, means were higher for people of higher socio-economic status compared to those of lower socio-economic status. People who reported an illness within the previous 2 weeks scored significantly lower on all scales compared to those who were healthy, as did people who said they had a disability or a chronic condition.     

Measuring the Functional Status and Well-Being of Patients with Migraine Headache

SYNOPSIS
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 £ 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.