Modelling Variability of Quality of Life Scores: A Study of Questionnaire Version and Bilingualism

Background and objectives: Modelling variability of quality of life scores can not only improve our understanding of the characteristics of the measurement tools, but also shed light on sample size requirements. Although the English and Chinese versions of the Short Form 36 Health Survey (SF-36) are commonly considered equivalent, they have not been compared in terms of variability. Furthermore, bilingual and monolingual persons may differ in cognition and responses to questionnaires. Methods: In a community-based survey of quality of life in Singapore, a society where both English and Chinese are widely used and bilingualism is prevalent, 2590 respondents answered either version of the SF-36. We studied the impact of questionnaire version and bilingualism on the variability of SF-36 scores by regression modelling, with adjustment for covariates. Results: The Chinese version had smaller variances in the physical functioning (PF) and the physical component summary scores than the English version. The variance ratios (VRs) were respectively 0.32 and 0.60 (each p < 0.01), controlling for covariates. Bilingualism was not associated with variability in SF-36 scores except PF (VR = 0.78; p < 0.05). Conclusions: As a result of a smaller variance, using the Chinese version of SF-36 among bilingual Chinese people may require a smaller sample size than using the English version.     

Health-related Quality of Life and Virologic outcomes in an HIV Clinic

Objective: The purpose of this study was to describe the relationship between viral load and health-related quality of life (HRQOL) in a cohort of persons with human immunodeficiency virus (HIV) infection. Design: We evaluated HRQOL measurements in a clinical cohort of HIV-positive patients recruited from a university-associated HIV primary care clinic. HRQOL instruments included the medical outcomes survey-short form-36(MOS-SF-36) from which mental and physical component summary scores (MCS and PCS) and subscale scores were calculated. Results: Significant negative associations were found between viral load and SF-36 PCS, physical functioning (PF), role-physical (RP), bodily pain (BP), general health (GH), role-emotional (RE), and vitality (VT). Similar negative associations were found between CD4 cell count and SF-36 summary and subscale scores, with the notable exception of bodily pain. Multivariate analyses controlling for the effects of CD4 cell count and other clinical variables indicated viral load as an independent predictor of SF-36 PCS, RP, BP and VT scores. Conclusions: The relationship between viral load, a measure of HIV disease activity, and several dimensions of the SF-36, a patient-focused measure of HRQOL, appears to be strong and independent of CD4 cell count. These findings suggest that having a lower viral load positively impacts the quality of life of HIV-positive patients. This revised version was published online in July 2006 with corrections to the Cover Date.     

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. This revised version was published online in June 2006 with corrections to the Cover Date.     

Is the standard SF-12 Health Survey valid and equivalent for a Chinese population?

Introduction: Chinese is the worlds largest ethnic group but few health-related quality of life (HRQoL) measures have been tested on them. The aim of this study was to determine if the standard SF-12 was valid and equivalent for a Chinese population. Methods: The SF-36 data of 2410 Chinese adults randomly selected from the general population of Hong Kong (HK) were analysed. The Chinese (HK) specific SF-12 items and scoring algorithm were derived from the HK Chinese population data by multiple regressions. The SF-36 PCS and MCS scores were used as criteria to assess the content and criterion validity of the SF-12. The standard and Chinese (HK) specific SF-12 PCS and MCS scores were compared for equivalence. Results: The standard SF-12 explained 82% and 89% of the variance of the SF-36 PCS and MCS scores, respectively, and the effect size differences between the standard SF-36 and SF-12 scores were less than 0.3. Six of the Chinese (HK) specific SF-12 items were different from those of the standard SF-12, but the effect size differences between the Chinese (HK) specific and standard SF-12 scores were mostly less than 0.3. Conclusions: The standard SF-12 was valid and equivalent for the Chinese, which would enable more Chinese to be included in clinical trials that measure HRQoL.     

Comparison of WHOQOL-BREF and SF-36 in patients with HIV infection

The purpose of the study was to evaluate the reliability and validity of the two generic instruments, the WHOQOL and the SF-36, for assessing health-related quality of life in 224 patients with HIV infection. The internal consistency ranged from 0.75 to 0.86 across the WHOQOL-BREF domains and from 0.72 to 0.93 across the SF-36 scales. The scores of all WHOQOL-BREF domains and SF-36 scales correlated positively with the measure of happiness, Sat-HRQOL and self-perceived health status, and correlated negatively with the number and intensity of symptoms. Patients with higher CD4 cell counts scored significantly higher on G4 (general health), three WHOQOL-BREF domains, seven SF-36 scales, and PCS (physical component summary). Patients with fewer symptoms and with less intensity of symptoms had significantly higher scores on all four domains of WHOQOL-BREF, eight scales, PCS, and MCS (mental component summary) of the SF-36 scale. The correlations between the physical, psychological, and social domains of the WHOQOL-BREF and PF (physical functioning), MH (mental health), and SF (social functioning) of the SF-36 were 0.51, 0.75, and 0.54, respectively. There is also good correlation between PCS of the SF-36 and the physical domain of the WHOQOL-BREF (r = 0.48), and between MCS and all four domains of the WHOQOL-BREF (r range = 0.60–0.75). The WHOQOL-BREF domains showed fewer floor or ceiling effect than the SF-36 scales. We concluded that both the WHOQOL-BREF and the SF-36 are reliable and valid health related quality-of-life instruments in patients with HIV infection.     

Predicting an SF-6D Preference-Based Score Using MCS and PCS Scores from the SF-12 or SF-36

Background:  The SF-6D preference-based scoring system was developed several years after the SF-12 and SF-36 instruments. A method to predict SF-6D scores from information in previous reports would facilitate backwards comparisons and the use of these reports in cost-effectiveness analyses.
Methods:  This report uses data from the 2001–2003 Medical Expenditures Panel Survey (MEPS), the Beaver Dam Health Outcomes Survey, and the National Health Measurement Study. SF-6D scores were modeled using age, sex, mental component summary (MCS) score, and physical component summary (PCS) score from the 2002 MEPS. The resulting SF-6D prediction equation was tested with the other datasets for groups of different sizes and groups stratified by age, MCS score, PCS score, sum of MCS and PCS scores, and SF-6D score.
Results:  The equation can be used to predict an average SF-6D score using average age, proportion female, average MCS score, and average PCS score. Mean differences between actual and predicted average SF-6D scores in out-of-sample tests was −0.001 (SF-12 version 1), −0.013 (SF-12 version 2), −0.007 (SF-36 version 1), and −0.010 (SF-36 version 2). Ninety-five percent credible intervals around these point estimates range from ±0.045 for groups with 10 subjects to ±0.008 for groups with more than 300 subjects. These results were consistent for a wide range of ages, MCS scores, PCS scores, sum of MCS and PCS scores, and SF-6D scores. SF-6D scores from the SF-36 and SF-12 from the same data set were found to be substantially different.
Conclusions:  Simple equation predicts an average SF-6D preference-based score from widely published information.     

Do differences in methods for constructing SF-36 physical and mental health summary measures change their associations with chronic medical conditions and utilization?

Background and objective: Various approaches have been employed to derive physical health and mental health summary scores for the SF-36 and the RAND-36, but head-to-head comparisons of alternative scoring algorithms are rare. We determined whether the associations of the physical and mental health summary scores with chronic medical conditions and utilization would differ depending on the scoring algorithm used. Methods: We examined 5701 patients receiving medical care from an independent association of 48 physician groups located primarily in the western United States and compared SF-36 and RAND-36 scoring of physical health and mental health summary scores. Associations with the presence of diabetes, heart disease, and kidney disease, as well as with utilization of medical care and mental health care were compared using bivariate and multivariate analysis. To examine the relationship between SF-36 and RAND-36 scores, we regressed the SF-36 physical and mental health composite scores on the RAND-36 physical and mental health summary measures and vice versa. Results: We found that the SF-36 and RAND-36 summary scores generally yielded results similar to one another across measures of heart disease, diabetes, and kidney disease, as well as measures of utilization. However, for each chronic medical condition, the RAND-36 showed a slightly larger decrement in mental health than did the SF-36. Conclusions: Differences between the two sets of summary scores were consistent with their respective conceptual and analytic approaches. Where comparisons of results between the SF-36 and RAND-36 summary scores are desirable in future studies, they can be estimated using the regression equations derived in this study.     

The equivalence of English and Chinese SF-36 versions in bilingual Singapore Chinese

Objective: To assess the equivalence of English and Chinese versions of the SF-36. Methods: Using a crossover design with block randomisation and stratification by age, identical English or Chinese questionnaires containing the English (UK) and Chinese (HK) SF-36 versions were administered 3–16 days apart to 168 free-living, bilingual, ethnic Chinese volunteers in Singapore. Item level equivalence of both versions was assessed by comparing item means and orderings within each scale. Scale level equivalence was assessed by comparing internal consistency (Cronbach's ), results of factor analysis and mean scale scores (using paired t-tests and intra-class correlations). Results: Item and scale level comparisons supported the equivalence of both versions. For both the versions, item means, item ordering and Cronbach's were similar, and factor analysis yielded two factors with similar factor loadings. There was no clinically important difference in mean scale scores for seven of eight scales, and intra-class correlations were excellent/good for five scales (0.69–0.77) and moderate for three scales (0.55–0.57). Conclusion: English (UK) and Chinese (HK) SF-36 versions are equivalent in bilingual Singapore Chinese. Our data suggest that SF-36 scores from English- and Chinese-speaking subjects may be combined in studies using the SF-36, increasing the power and representativeness of such studies.     

The SF-36 summary scales were valid, reliable, and equivalent in a Chinese population

OBJECTIVES: To find out whether the SF-36 physical and mental health summary (PCS and MCS) scales are valid and equivalent in the Chinese population in Hong Kong (HK). STUDY DESIGN AND SETTING: The SF-36 data of a cross-sectional study on 2,410 Chinese adults randomly selected from the general population in HK were analyzed. RESULTS: The hypothesized two-factor structure of the physical and mental health summary scales (PCS and MCS) was replicated and the expected differences in scores between known morbidity groups were shown. The internal reliability coefficients of the PCS and MCS scales ranged from 0.85 to 0.87. The effect size differences between the U.S. standard and HK-specific PCS and MCS scores were mostly <0.5. The effect size differences in the standard PCS and MCS scores of specific groups between the U.S. and H.K. populations were all <0.5. CONCLUSION: The PCS and MCS scales were applicable to the Chinese population in HK. The high level of measurement equivalence of the scales between the U.S. and H.K. populations suggests that data pooling between the two populations could be possible. To our knowledge, this is the first study to show that the SF-36 summary scales are valid and equivalent in an Asian population.     

Reliability and validity of the English (Singapore) and Chinese (Singapore) versions of the Short-Form 36 version 2 in a multi-ethnic Urban Asian population in Singapore

Purpose

We aimed to evaluate the measurement properties of the Singapore English and Chinese versions of the Short-Form 36 version 2 (SF-36v2) Questionnaire, an improved version of the widely used SF-36, for assessing health-related quality of life (HRQoL) in a multi-ethnic urban Asian population in Singapore.

Methods

SF-36v2 scores and data on medical history, demographic and lifestyle factors from the Singapore Prospective Study Programme were analyzed. Convergent and divergent validity, internal consistency, floor and ceiling effects, known group validity and factor structure of the SF-36v2 were assessed for the English and Chinese versions, respectively.

Results

Complete data for 4,917 participants (45.8 %) out of 10,747 eligible individuals were analyzed (survey language: 4,115 English and 802 Chinese). Item-scale correlations exceeded 0.4 for all items of the English SF-36v2 and for all except one item of the Chinese SF-36v2 (bathe and dress: item-scale correlation: 0.36). In the English SF-36v2, Cronbach’s alpha exceeded 0.70 for all scales. In the Chinese SF-36v2, Cronbach’s alpha exceeded 0.7 on all scales except social functioning (Cronbach’s alpha: 0.68). For known groups validity, respondents with chronic medical conditions expectedly reported lower SF-36v2 score on most English and Chinese SF-36v2 scales. In confirmatory factor analysis, the Singapore three-component model was favored over the United States two-component and Japan three-component models.

Conclusions

The English and Chinese SF-36v2 are valid and reliable for assessing HRQoL among English and Chinese-speaking Singaporeans. Test–retest reliability and responsiveness of the English and Chinese SF-36v2 in Singapore remain to be evaluated.     

Equivalence of Chinese and US–English Versions of the SF-36 Health Survey

This study evaluated the equivalence of Chinese and US–English versions of the SF-36 Health Survey in a convenience sample of 309 Chinese nationals bilingual in Chinese and English living in a US city. Snowball sampling was used to generate sufficient sample size. Internal consistency, test–retest, and equivalent-forms reliability were estimated. Patients were randomized to one of four groups: (1) English version completed first, followed by Chinese version (same occasion); (2) Chinese version completed first, followed by English version (same occasion); (3) English version completed once and then again 1-week later; (4) Chinese version completed once and then again 1-week later. Internal consistency reliability estimates for the Chinese and US–English versions of the SF-36 scales ranged from 0.60 to 0.88; test–retest reliability estimates (1 week time interval) ranged from 0.67 to 0.90. Reliability estimates for corresponding Chinese and US–English SF-36 scales tended to be similar and not significantly different. Equivalent-forms reliability estimates (product–moment correlations) ranged from 0.81 to 0.98. Mean SF-36 scale scores were comparable for both versions of the instrument. This study provides support for the equivalence of the Chinese and US–English versions of the SF-36.     

Measuring Stroke Impact with SIS: Construct Validity of SIS Telephone Administration

Objectives: The purpose of this study was to examine the construct validity of the Stroke Impact Scale (SIS) using telephone mode of administration. Methods: Stroke patients were identified using national VA administrative data and ICD-9 codes in 13 participating VA hospitals. Stroke was confirmed by reviewing electronic medical records. Patients were administered SIS by telephone at 12-weeks post-stroke, and administered the Functional Independence Measure (FIM) and SF-36V at 16 weeks post-stroke. The instrument’s convergent validity and its ability to differentiate between groups of stroke patients with different disability levels were examined using Pearson’s correlations and Kruskal–Wallis one way ANOVA tests. Results: All the relevant relationships yielded high correlation coefficients with statistical significance: 0.86 for FIM-motor vs. SIS-ADL, and 0.77 for PF in SF-36V vs. SIS-PHYSICAL. The SIS presented better score discrimination and distribution for different severity of stroke than FIM and SF-36V without severe ceiling and floor effects. Kruskal–Wallis tests showed the Physical Component Score of SF-36V did not discriminate any disability levels. Physical functioning (PF) in SF-36V, FIM-motor, SIS-PHYSICAL, SIS-16, and SIS-ADL showed better discrimination in person’s functioning. The pairwise comparisons showed that SIS-PHYSICAL, SIS-16, and SIS-ADL discriminated more Rankin levels than FIM-motor and PF in SF-36V. Conclusions: SIS telephone survey had superior convergent validity and was better at differentiating between groups of stroke patients with different disability levels than the FIM and SF-36V with no evidence of ceiling and floor effects. Telephone administration of SIS would be a useful and cost-effective method to follow-up community dwelling veterans with stroke.     

The SF-36: A simple, effective measure of mobility-disability for epidemiological studies

Background  Mobility disability is a major problem in older people. Numerous scales exist for the measurement of disability but often these do not permit comparisons between study groups. The physical functioning (PF) domain of the established and widely used Short Form-36 (SF-36) questionnaire asks about limitations on ten mobility activities. Objectives  To describe prevalence of mobility disability in an elderly population, investigate the validity of the SF-36 PF score as a measure of mobility disability, and to establish age and sex specific norms for the PF score. Methods  We explored relationships between the SF-36 PF score and objectively measured physical performance variables among 349 men and 280 women, 59–72 years of age, who participated in the Hertfordshire Cohort Study (HCS). Normative data were derived from the Health Survey for England (HSE) 1996. Results  32% of men and 46% of women had at least some limitation in PF scale items. Poor SF-36 PF scores (lowest fifth of the gender-specific distribution) were related to: lower grip strength; longer timed-up-and-go, 3m walk, and chair rises test times in men and women; and lower quadriceps peak torque in women but not men. HSE normative data showed that median PF scores declined with increasing age in men and women. Conclusion  Our results are consistent with the SF-36 PF score being a valid measure of mobility disability in epidemiological studies. This approach might be a first step towards enabling simple comparisons of prevalence of mobility disability between different studies of older people. The SF-36 PF score could usefully complement existing detailed schemes for classification of disability and it now requires validation against them.     

Trajectories and associated factors of quality of life,global outcome,and post-concussion symptoms in the first year following mild traumatic brain injury

Purpose

To investigate the associated factors and change trajectories of quality of life (QoL), global outcome, and post-concussion symptoms (PCS) over the first year following mild traumatic brain injury (mTBI).

Methods

This was a prospective longitudinal study of 100 participants with mTBI from neurosurgical outpatient departments in Chiayi County District Hospitals in Taiwan. The checklist of post-concussion syndromes (CPCS) was used to assess PCS at enrollment and at 1, 3, and 12 months after mTBI; the glasgow outcome scale extended (GOSE), the quality of life after brain injured (QOLIBRI), Chinese version, and the Short Form 36 Health Survey (SF-36), Taiwan version, were used to assess mTBI global outcome and QoL at 1, 3, and 12 months after mTBI.

Results

Latent class growth models (LCGMs) indicated the change trajectories of QOLIBRI, PCS SF-36, MCS SF-36, GOSE, and PCS. Classes of trajectory were associated with age ≥40 years, unemployment at 1 month after injury, and educational level ≤12 years. Univariate analysis revealed that employment status at 1 month post-injury was correlated with the trajectories of QOLIBRI, PCS SF-36, MCS SF-36, and GOSE, but not PCS.

Conclusions

Employment status was the most crucial associated factor for QoL in individuals with mTBI at the 1-year follow-up. Future studies should explore the benefits of employment on QoL of individuals with mTBI.

     

Use of the SF-8 to assess health-related quality of life for a chronically ill,low-income population participating in the Central Louisiana Medication Access Program (CMAP)

Objectives: The utility of the SF-8 for assessing health-related quality of life (HRQL) is demonstrated. Race and gender differences in physical component (PCS) and mental component (MCS) summary scores among participants in the CENLA Medication Access Program (CMAP), along with comparisons to the United States population are made. Methods: Age-adjusted multiple linear regression analyses were used to compare 1687 CMAP participants to the US population. Internal race and gender comparisons, adjusting for age and the number of self reported diagnoses, were also obtained. The paired t-test was used to assess 6-month change in PCS and MCS scores for a subset of 342 participants. Results: CMAP participants have PCS and MCS scores that are significantly 10–12 points lower than the US population, indicating lower self-reported HRQL. Females have significantly higher PCS and significantly lower MCS than males. African–Americans have significantly higher MCS than Caucasians. Significant increases in both PCS and MCS were observed for the subset of participants after 6months of intervention. Conclusions: The expected lower baseline PCS and MCS measures and the expected associations with age and number of diagnoses indicate that the SF-8 survey is an effective tool for measuring the HRQL of participants in this program. Preliminary results indicate significant increases in both PCS and MCS 6months after intervention.     

Relationships between self-reported health related quality of life and measures of standardized exercise capacity and metabolic efficiency in a middle-aged and aged healthy population

Background: The purpose of this study was to evaluate to what extent self-reported health related quality of life (HRQL), assessed by the Swedish standard version of the Medical Outcome Study Short-Form 36 (SF-36), is related to measured exercise capacity and metabolic efficiency in a cohort of healthy subjects from the Gothenburg area of Sweden. Material and methods: Individuals were invited to take part in the evaluation where HRQL was compared with the maximal power output expressed in Watts assessed during a standardized treadmill test with incremental work loads. Whole body respiratory gas exchanges (CO₂/O₂) were simultaneously measured. Estimate of metabolic efficiency was derived from oxygen uptake per Watt produced (ml O₂/min/W) near maximal work. Results: The health status profile in the current population largely agreed with normative data from an age- and gender-matched reference group, although some measured scores were slightly better than reference scores. Males and females had a similar relationship between energy cost (ml O₂/min) for production of maximal work (W), while the regressions for maximal exercise power and age were significantly different between males and females (p < 0.01). The overall metabolic efficiency was the same in individuals between 40 and 74 years of age (10.4 ± 0.07 ml O₂/min/Watt). Maximal exercise power was only related to the SF-36 subscale physical functioning (PF), but unrelated to other physical subscales such as role limitations due to physical problems, good general health and vitality. There was also a discrepancy between measured maximal power and PF in many subjects, particularly in males who experienced either intact or severely reduced PF. Conclusions: Our results demonstrate that simultaneous measurements of self-reported and objective measures of PF should add a more integrated view for evaluation of therapeutic effectiveness, since the overall correlation was poor between objective and subjective scores among individuals.     

Use of both short musculoskeletal function assessment questionnaire and short form-36 among tibial-fracture patients was redundant

ObjectiveTo compare the Short Musculoskeletal Function Assessment Dysfunction Index (SMFA DI) and the Short Form-36 Physical Component Summary (SF-36 PCS) scores among patients undergoing operative management of tibial fractures.Study Design and SettingBetween July 2000 and September 2005, we enrolled 1,319 skeletally mature patients with open or closed fractures of the tibial shaft that were managed with intramedullary nailing. Patients were asked to complete the SMFA Questionnaire and SF-36 at discharge and 3, 6, and 12 months post–surgical fixation.ResultsThe SMFA DI and SF-36 PCS scores were highly correlated at 3, 6, and 12 months post–surgical fixation. The difference in the mean standardized change scores for SMFA DI and SF-36 PCS, from 3 to 12 months post–surgical fixation, was not statistically significant. Both the SMFA DI and SF-36 PCS scores were able to discriminate between healed and nonhealed tibial fractures at 3, 6, and 12 months postsurgery.ConclusionIn patients with tibial-shaft fractures, the SMFA DI offered no significant advantages over the SF-36 PCS score. These results, along with the usefulness of SF-36 for comparing populations, recommend the SF-36 for assessing physical function in studies of patients with tibial fractures.     

Do SF-36 summary component scores accurately summarize subscale scores?

Standard scoring algorithms were recently made available for aggregating scores from the eight SF-36 subscales in two distinct, higher-order summary scores: Physical Component Summary (PCS) and Mental Component Summary (MCS). Recent studies have suggested, however, that PCS and MCS scores are not independent and may in part be measuring the same constructs. The aims of this paper were to examine and illustrate (1) relationships between SF-36 subscale and PCS/MCS scores, (2) relationships between PCS and MCS scores, and (3) their implications for interpreting research findings. Simulation analyses were conducted to illustrate the contributions of various aspects of the scoring algorithm to potential discrepancies between subscale profile and summary component scores. Using the Swedish SF-36 normative database, correlation and regression analyses were performed to estimate the relationship between the two components, as well as the relative contributions of the subscales to the components. Discrepancies between subscale profile and component scores were identified and explained. Significant correlations (r = −0.74, −0.67) were found between PCS and MCS scores at their respective upper scoring intervals, indicating that the components are not independent. Regression analyses revealed that in these ranges PCS primarily measures aspects of mental health (57% of variance) and MCS measures physical health (65% of variance). Implications of the findings were discussed. It was concluded that the current PCS/MCS scoring procedure inaccurately summarizes subscale profile scores and should therefore be revised. Until then, component scores should be interpreted with caution and only in combination with profile scores. This revised version was published online in June 2006 with corrections to the Cover Date.     

Does being bilingual in English and Chinese influence changes in quality of life scale scores? Evidence from a prospective,population based study

Background: Bilinguals differ from monolinguals in language use, but the influence of bilingualism on changes in Health-Related Quality of Life (HRQoL) scores is not known. Objective: To determine the influence of bilingualism on changes in HRQoL scores. Research design: A prospective cohort study of a population-based, disproportionately stratified random sample of monolingual or bilingual ethnic Chinese who completed the Short-Form 36 Health Survey (SF-36) in English or Chinese twice in 2 years. Least squares regression models were used to assess the influence of bilingualism on SF-36 scores, while adjusting for the influence of questionnaire language and determinants of HRQoL. Results: Usable English and Chinese questionnaires were returned by 1013 and 910 subjects respectively (aged 21–65 years, 48.5% female, 52.8% bilingual). Bilinguals differed from monolinguals in known determinants of HRQoL (being younger and better educated), changes in determinants of HRQoL over 2 years (more bilinguals had changes in work or marital status) and had mean SF-36 scores that were up to 10 points higher than monolinguals. After adjusting for these differences, bilingualism did not influence 2 year change scores for any of 8 SF-36 scales. Conclusion: Bilingualism did not influence changes in HRQoL scores over 2 years in this large, population-based study of subjects fluent in English and/or Chinese (representing an alphabet and/or pictogram based language respectively).     

Validation of the SF-36 in patients with endometriosis

Objectives

Endometriosis presents with significant pain as the most common symptom. Generic health measures can allow comparisons across diseases or populations. However, the Medical Outcomes Study Short Form 36 (SF-36) has not been validated for this disease. The goal of this study was to validate the SF-36 (version 2) for endometriosis.

Methods

Using data from two clinical trials (N = 252 and 198) of treatment for endometriosis, a full complement of psychometric analyses was performed. Additional instruments included a pain visual analog scale (VAS); a physician-completed questionnaire based on patient interview (modified Biberoglu and Behrman—B&B); clinical global impression of change (CGI-C); and patient satisfaction with treatment.

Results

Bodily pain (BP) and the Physical Component Summary Score (PCS) were correlated with the pain VAS at baseline and over time and the B&B at baseline and end of study. In addition, those who had the greatest change in BP and PCS also reported the greatest change on CGI-C and patient satisfaction with treatment. Other subscales showed smaller, but significant, correlations with change in the pain VAS, CGI-C, and patient satisfaction with treatment.

Conclusions

The SF-36—particularly BP and the PCS—appears to be a valid and responsive measure for endometriosis and its treatment.