Functional Capacity Evaluation in Subjects with Early Osteoarthritis of Hip and/or Knee; is Two-Day Testing Needed?

Introduction The Work Well Functional Capacity Evaluation (WW FCE) is a two-day performance based test consisting of several work-related activities. Three lifting and carrying test items may be performed on both days. The objective of this study was to assess the need for repeated testing of these items in subjects with early osteoarthritis of the hip and/or the knee and to analyze sources of variation between the 2 days of measurement. Methods A standardized WW FCE protocol was applied, including repeated testing of lifting low, lifting overhead and carrying. Differences and associations between the 2 days were calculated using paired samples t-tests, intraclass correlation coefficients (ICC) and limits of agreement (LoA). Possible sources of individual variation between the 2 days were identified by Wilcoxon signed ranks tests. Pearson correlation coefficients were calculated for differences in performances between days and differences in possible sources of variation between days. Results Seventy-nine subjects participated in this study, their mean (SD) age was 56.6 (4.8) years, median (min–max) WOMAC (Western Ontario and McMaster Universities) index scores for pain, stiffness and physical function were 5 (0–17), 3 (0–7) and 14 (0–49), respectively. Median (min–max) SF36 physical function was 75 (5–95), and SF36 pain score was 67 (12–76). Mean performance differences ranged from −0.2 to −0.8 kg (P > 0.05). ICC’s ranged from 0.75 (lifting overhead) to 0.88 (lifting low). LoA were: lifting low 8.0 kg; lifting overhead 6.5 kg; carrying 9.0 kg. Pearson’s correlations were low and non-significant. Conclusions All three tests show acceptable two-day consistency. WW FCE testing on two consecutive days is not necessary for groups of subjects with early osteoarthritis. Individual sources of variation could not be identified.     

Is Psychometric Scoring of the McNew Quality of Life After Myocardial Infarction Questionnaire Superior to the Clinimetric Scoring? A Comparison of the Two Approaches

Objective: ‘Clinimetric’ and ‘psychometric’ approaches are currently used to develop health related quality of life questionnaires. The Quality of Life after Myocardial Infarction questionnaire (QLMI) was originally developed using ‘clinimetric’ criteria; it was subsequently modified (McNew QLMI) and a new domain structure was defined using factor analysis. The objective of this study was to compare the measurement properties of the McNew QLMI scores when both approaches for scoring are used. Methods: The McNew QLMI and SF-36 were administered to patients 2 weeks and 2 months after myocardial infarction. Two sets of scores for the McNew QLMI were computed using the original ‘clinimetric’ and the subsequent ‘psychometrically’ derived scoring systems. Reliability statistics for the two sets of domains were compared and construct validity was assessed by establishing a priori hypotheses on the expected correlation between each score and the dimensions of the SF-36. Results: Both sets of scores had similar reliability (Cronbach’s α between 0.64 and 0.93) and responsiveness (SRMs between 0.17 and 0.87) while validity was better for the ‘clinimetric’ set of scores (concordance between observed and expected correlations was moderate for the ‘clinimetric’ scores and fair for the ‘psychometric’ scores). Conclusion: Since overall measurement properties of the ‘clinimetrically’ scored McNew QLMI are better than the ‘psychometrically’ scored version, we suggest that either the original ‘clinimetric’ system is used or that an improved ‘psychometric’ version is developed.     

Is a Generic Quality of Life Instrument Helpful for Evaluating Women with Urinary Incontinence?

Objectives: The aim of this study was to determine whether a generic health outcome instrument would be helpful for evaluating women with stress urinary incontinence (UI) combined with or without urge UI. Methods: A total of 109 women with UI and 80 controls participated in the study. Health-related quality of life (QOL) was measured using the Medical Outcomes Study 36-Item Short-Form General Health Survey (SF-36) and the Incontinence Quality of Life (I-QoL) questionnaire. Results: Among eight domains of the SF-36 questionnaire, only four domains, namely, ‘role-physical functioning’ (p<0.05), ‘vitality’ (p<0.05), ‘mental health’ (p<0.05) and ‘bodily pain’ (p<0.05) were significantly different between the groups. Comparing the I-QoL sores in the two groups, patients with UI had significantly poorer subscale scores of I-QoL than the controls (p<0.05 for all domains). When women with UI were subdivided into groups of stress and mixed UI, only 2 domains of the SF-36 questionnaire, ‘role-physical functioning’ (p<0.05) and ‘bodily pain’ (p<0.05), were significantly different. The mixed UI group had higher scores only on these two domains compared to the stress UI group. In the ‘role-physical functioning’ domain, there was no significant difference between the mixed UI group and the controls. In ‘bodily pain’ domain, there was no significant difference between the stress UI group and the controls. The mixed group had the highest scores observed. Patients with mixed UI had significantly lower total scores compared to those with stress UI, including the subscale score of ‘avoidance behavior’ of the I-QoL. Among eight domains of the SF-36, only ‘physical functioning’ (r = 0.281, p<0.01) and ‘social functioning’ (r = 0.239, p<0.05) were weakly correlated with ‘psychological impact’ of the I-QoL. Conclusion: Our findings show that the generic QOL instrument is not sensitive measure of QOL in women with UI.     

Psychometric properties of the Japanese version of the quality of life-Cancer Survivors Instrument

The purpose of this study was to describe the psychometric properties of the Japanese version of the Quality of Life-Cancer Survivors Instrument (QOL-CS-J) developed in the U.S. This study was conducted as a mail survey to survivors of more than 5 years post curative resection for non-small-cell lung cancer (NSCLC) and who had participated in an earlier survey. This survey included the medical and demographic factors, the QOL-CS scores, and the Medical Outcome Study 36-Item Short Form (SF-36). A total of 113 survivors completed the survey. To confirm the reliability, the Cronbach’s α coefficient of each subscale was calculated as an internal consistency (α = 0.65–0.89). To confirm the validity of the trial as conducted, Pearson’s correlation coefficients between the subscales of the QOL-CS and the subscales of the SF-36 were calculated. There were moderate correlations between associated subscales including QOL-CS physical to SF-36 bodily pain (r = 0.45) and vitality (r = 0.52), QOL-CS psychological to SF-36 mental health (r = 0.55), QOL-CS social to SF-36 general health perception (r = 0.31) and mental health (r = 0.47), and QOL-CS total to each subscale of SF-36 (r = 0.25–0.64). Findings demonstrated that the QOL-CS-J adequately measured the QOL in long-term NSCLC survivors.     

Iron deficiency, general health and fatigue: Results from the Australian Longitudinal Study on Women's Health

Associations between self-reported ‘low iron’, general health and well-being, vitality and tiredness in women, were examined using physical (PCS) and mental (MCS) component summary and vitality (VT) scores from the MOS short-form survey (SF-36). 14,762 young (18–23 years) and 14,072 mid-age (45–50 years) women, randomly selected from the national health insurance commission (Medicare) database, completed a baseline mailed self-report questionnaire and 12,328 mid-age women completed a follow-up questionnaire 2 years later. Young and mid-age women who reported (ever) having had ‘low iron’ reported significantly lower mean PCS, MCS and VT scores, and greater prevalence of ‘constant tiredness’ at baseline than women with no history of iron deficiency [Differences: young PCS = −2.2, MCS = −4.8, VT = −8.7; constant tiredness: 67% vs. 45%; mid-age PCS = −1.4, MCS = −3.1, VT = −5.9; constant tiredness: 63% vs. 48%]. After adjusting for number of children, chronic conditions, symptoms and socio-demographic variables, mean PCS, MCS and VT scores for mid-age women at follow-up were significantly lower for women who reported recent iron deficiency (in the last 2 years) than for women who reported past iron deficiency or no history of iron deficiency [Means: PCS – recent = 46.6, past = 47.8, never = 47.7; MCS – recent = 45.4, past = 46.9, never = 47.4; VT – recent = 54.8, past = 57.6, never = 58.6]. The adjusted mean change in PCS, MCS and VT scores between baseline and follow-up were also significantly lower among mid-age women who reported iron deficiency only in the last 2 years (i.e. recent iron deficiency) [Mean change: PCS = −3.2; MCS = −2.1; VT = −4.2]. The results suggest that iron deficiency is associated with decreased general health and well-being and increased fatigue. This revised version was published online in June 2006 with corrections to the Cover Date.     

Long-Term Health and Work Outcomes of Renal Transplantation and Patterns of Work Status During the End-Stage Renal Disease Trajectory

Introduction The aim of this study was to examine the health- and work outcomes of renal transplant recipients long-term after transplantation as well as the pattern of work status, work ability and disability benefits during the end-stage renal disease (ESRD) trajectory that precedes transplantation. Methods 34 transplant recipients completed interviews 3, 13 months and >6 years posttransplantation. Health status (SF-36), work ability (WAI), and fatigue (CIS) were assessed by questionnaires, clinical data were derived from medical charts, and data on functional limitations were extracted from the social security system database. The work status trajectory preceding transplantation was examined retrospectively. Results Of the 34 third wave transplant recipients, 29% were severely fatigued. Compared with the general working population, recipients experienced worse general health and less vitality. Non-working recipients had worse renal function and general health, and more limitations in physical functioning compared to working recipients. The WAI score indicated moderate work ability for 60% of the employed recipients. Although 67% were employed (45% parttime), 30% of those working still received some disability benefits. Social insurance physicians found variable levels of functional limitations. The mean work status trajectory showed more sickness absence and less work ability during dialysis, but after transplantation, both work status and work ability generally improved. Conclusions Transplant recipients have a compromised health status which leads to functional limitations and disability. Although work status improved after transplantation, a substantial number of the transplant recipients received disability benefits. The negative health consequences of anti-rejection medications may play an important role in long-term work ability. These results indicate that a ‘new’ kidney has advantages over dialysis with respect to work, but does not necessarily leads to ‘normal’ work outcomes.     

Reliability and validity of the SF-12v2 in the medical expenditure panel survey

Objective  Evaluate the reliability and validity of the Medical Outcomes Study Short-Form version 2 (SF-12v2) in the 2003–2004 Medical Expenditure Panel Survey (MEPS). Research design  Data were collected in the self-administered mail-out questionnaire and face-to-face interviews of the MEPS (n = 20,661). Internal consistency and test–retest reliability and construct, discriminate, predictive and concurrent validity were tested. The EQ-5D, perceived health and mental health questions were used to test construct and discriminate validity. Self-reported work, physical and cognitive limits tested predictive validity and number of chronic conditions assessed concurrent validity. Results  Both Mental Component Summary Scores (MCS) and Physical Component Summary Scores (PCS) were shown to have high internal consistency reliability (α > .80). PCS showed high test–retest reliability (ICC = .78) while MCS demonstrated moderate reliability (ICC = .60). PCS had high convergent validity for EQ-5D items (except self-care) and physical health status (r > .56). MCS demonstrated moderate convergent validity on EQ-5D and mental health items (r > .38). PCS distinguish between groups with different physical and work limitations. Similarly, MCS distinguished between groups with and without cognitive limitations. The MCS and PCS showed perfect dose response when variations in scores were examined by participant’s chronic condition status. Conclusions  Both component scores showed adequate reliability and validity with the 2003–2004 MEPS and should be suitable for use in a variety of proposes within this database.     

The Validity and Reliability of the Functional Impairment Checklist (FIC) in the Evaluation of Functional Consequences of Severe Acute Respiratory Distress Syndrome (SARS)

Severe acute respiratory distress syndrome (SARS) contributed to significant mortality and morbidity worldwide. We aimed to establish the validity, reliability and responsiveness of the functional impairment checklist (FIC) as a measurement tool for physical dysfunction in SARS survivors. One hundred and sixteeen (65 females and 51 males, mean age 45.6) patients who joined the SARS rehabilitation programme were analysed. The factor analysis yielded two latent factors. The mean FIC-symptom and FIC-disability score were 24.12 (SD ± 20.2) and 26.11 (SD ± 27.32), respectively. Based on the item-scale correlation coefficients, the Cronbach’s alpha coefficients reflecting the internal consistency reliability of scale score were 0.75 for FIC-symptom and 0.86 for FIC-disability. Test–retest reliability in 23 patients showed no statistical significant difference in the FIC scores between tests with intraclass correlation coefficient (ICC) 0.49–0.57. The FIC scales correlated both with 6 munute walking test (6MWT) distance (−0.26 and −0.38) and handgrip strength (HGS) (−0.20 and −0.27). Moreover, the FIC scales correlated with St. George’s respiratory questionnaire (SGRQ) (0.19 to 0.52) and short form 36 Hong Kong (SF-36) domains (−0.19 to −0.59). Both FIC scales correlated stronger with physical component summary (PCS) (−0.41 and −0.55) than with mental component summary (MCS) (−0.30 and −0.23). FIC reduced significantly at 6 months while the SF-36 PCS and MCS did not show any change. In conclusion, the study results indicate the FIC is reliable, valid and responsive to change in symptom and disability as a consequence of SARS, suggesting it may provide a means of assessing health related quality of life (HRQOL) outcomes in a longitudinal follow up.     

Self-reported physical functioning was more influenced by pain than performance-based physical functioning in knee-osteoarthritis patients

BACKGROUND AND OBJECTIVES: To test the hypothesis that self-reported physical functioning is more influenced by pain than performance-based physical functioning. METHODS: 163 knee-osteoarthritis patients completed the performance-based DynaPort KneeTest (DPKT), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and SF-36 (self-report measures of pain and physical functioning) before, 3, 6, and 12 months after knee replacement. RESULTS: Correlations between (two) self-reported measures of functioning and (two) pain measures were higher (0.57-0.74) than correlations between the performance-based measure of functioning and the two pain measures (0.20 and 0.26). In factor analysis, WOMAC and SF-36 pain and physical functioning subscores loaded on the first factor (eigenvalue 3.2), while DPKT KneeScore2 loaded on the second factor (eigenvalue 0.92). Before surgery, correlations between performance-based and self-reported physical functioning were higher in patients with less pain (0.43) compared to patients with more pain (0.17), for the WOMAC (as expected), but not for the SF-36. After surgery, when the pain had diminished, the correlations between performance-based and self-reported physical functioning were higher, especially for the WOMAC. CONCLUSIONS: Our hypothesis was convincingly supported by the results of the WOMAC, and somewhat less by the results of the SF-36. We consider this as evidence for a lack of content validity of the WOMAC.     

Functional Self-Efficacy Beliefs Influence Functional Capacity Evaluation

Objectives: The relationship between functional self-efficacy and Functional Capacity Evaluation (FCE) lift performance was examined in workers’ compensation claimants’ with low back pain. Methods: A cross-sectional design was used. Forty-two claimants with back pain and 38 subjects without back pain were enrolled. Subjects completed a measure of functional self-efficacy related specifically to lifting. Subjects also underwent FCE floor-to-waist, waist-to-overhead and horizontal lift testing. Potential confounders were also assessed including perceived disability, pain intensity, and self-rated health. Analysis included Pearson correlation and multivariable linear regression. Results: Higher functional self-efficacy beliefs were highly associated with better FCE performance on each of the lift items tested (r = 0.50–0.73). In multivariable analysis, the measure of functional self-efficacy remained independently associated with lift performance after controlling for potential confounders. Conclusion: Functional self-efficacy beliefs appear to influence FCE lift performance. Strategies for altering functional self-efficacy beliefs and their resulting impact on patient functional performance and outcomes should be examined.     

Functional Limitations and Well-Being in Injured Municipal Workers: A Longitudinal Study

Two instruments, the Health Assessment Questionnaire (HAQ) and the Short Form-36 (SF-36), were used to document both the immediate and short-term effects of workplace injuries in municipal workers. Telephone interviews were conducted up to 3 months following the injury. One hundred fourteen subjects agreed to participate in the study; 90 workers completed at least one useable interview. The relationship between functional limitation and lost days was evaluated using Cox proportional hazards models. At 3 months following the onset of injury, SF-36 scores for physical function, role-physical, and bodily pain differed significantly from population norms. Using one standard deviation of change, statistically significant hazard ratios were seen in subjects with lower SF-36 physical component summary, physical function, and bodily pain scores, and higher HAQ disability and fatigue scores. Functional limitations persisted in workers after relatively minor workplace injuries despite a 91% return to work rate.     

The association between infant feeding pattern and mother’s quality of life in Taiwan

Background This study compared the health-related quality of life (HRQOL) of mothers using different infant feeding methods. Methods We used the Medical Outcomes Study 36-item Short-Form (SF-36) to measure the HRQOL of 1,747 mothers and used the scores to look for associations with infant feeding methods (not breastfeeding, breastfeeding for <1 month, breastfeeding 1–5 months, and still breastfeeding at the 6th month). The mothers were chosen via a stratified sampling from the Taiwan national birth registration data between November and December 2003. Results HRQOL and breastfeeding duration were positively associated. Of the eight unadjusted domain scores of the SF-36, general health perception and mental health were significantly different among these four different infant feeding groups (P < 0.05). After controlling for potential confounding factors, mothers who breastfed for 6 months or longer had a higher HRQOL score than the other mothers. In addition, their physical functioning, general health perception and mental health scores were higher than those of mothers who did not breastfeed (P < 0.05). Mother’s family income and parity and child’s health status were also associated with mother’s quality of life. Conclusions Compared to the other mothers, mothers who breastfed for six moths or longer had better HRQOL. However, the limitation that this study was cross-sectional in design should be considered and further studies are needed.     

Problems with the performance of the SF-36 among people with type 2 diabetes in general practice

Objective: To validate the short form-36 (SF-36) among people with type 2 diabetes in general practice, and to make comparisons with the Audit of Diabetis Dependent Quality of Life (ADDQoL). Design: Postal survey with one reminder. Setting: Four general practices. Patients: One hundred and eighty-four eligible patients (30–70 years) with type 2 diabetes on 14 general practitioner lists. Measures: SF-36 response rates, distribution of dimension scores and internal consistency. Median scores in relation to sociodemography and self-reported health. Comparisons with ADDQoL scores. Results: One hundred and thirty-one patients responded (71%). Distributions of SF-36 dimension scores were mostly skewed. Internal consistency and construct validity were acceptable, with predictable sociodemographic trends. People with illness related to or unrelated to diabetes scored significantly lower on most dimensions. SF-36 dimension scores correlated best with relevant diabetes-specific ADDQoL scores amongst respondents reporting no comorbidity. Conclusions: Although valid and reliable, SF-36 scores are strongly affected by non-diabetic comorbidity in type 2 diabetes, supporting the complementary use of a diabetes-specific measure, providing information about the impact of diabetes specifically. This revised version was published online in June 2006 with corrections to the Cover Date.     

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.     

A Study of the Construct Validity of the Health Utilities Index Mark 3 (HUI3) in Patients with Schizophrenia

This study assessed the construct validity of the Health Utilities Index Mark 3 (HUI3) in patients with schizophrenia. Patients with schizophrenia recruited from a tertiary mental hospital in Singapore completed the HUI3, the Short-Form 36 Health Survey (SF-36) and the Schizophrenia Quality of Life Scale (SQLS). Patients were assessed for presence and absence of 22 common psychiatric symptoms. Construct validity was assessed using 6 a priori hypotheses. Two hundred and two patients (mean age: 37.8 years, female: 52%) completed the survey. As hypothesized, overall HUI3 utility scores were correlated with SF-36 measures (Spearman’s rho: 0.19 to 0.51), SQLS scales (Spearman’s rho: −0.56 to −0.36), and the number of psychiatric symptoms (Spearman’s rho: −0.49). The HUI3 emotion attribute was moderately correlated with SF-36 mental health (Spearman’s rho: 0.45) and SQLS psychosocial scales (Spearman’s rho: −0.43), and HUI3 pain attribute was strongly correlated with SF-36 bodily pain scale (Spearman’s rho: 0.58). The mean HUI3 overall, emotion, cognition, and speech scores for patients with schizophrenia were 0.07, 0.09, 0.04 and 0.04 points lower than respective age-, sex- and ethnicity-adjusted population norms (p<0.001 for all, ANCOVA). This study provides evidence for the construct validity of the HUI3 in patients with schizophrenia.     

Cultural adaptation and application of the IBS–QOL in China: a disease-specific quality-of-life questionnaire

Background Irritable bowel syndrome (IBS) is a chronic and episodic illness characterized by altered bowel habits and associated abdominal pain. At present, IBS is one of the most common functional gastrointestinal and motility disorders affecting countries around the world. Surveys have found that patients with IBS have a significantly lower health-related quality of life. Objectives The aim of this study was to translate and examine the validity of the Irritable Bowel Syndrome–Quality of Life questionnaire (IBS–QOL) in patients suffering from IBS in China. Methods A structured procedure was used for the translation and cultural adaptation of the original English IBS–QOL into Chinese. The questionnaire was administered to 73 clinical patients with IBS and␣70 healthy individuals. Psychometric testing for reliability, validity and responsiveness followed standardized procedures. Test–retest reliability (10–20 hours) was assessed using the clinical patients. Follow-up (4 weeks) was collected for 61 clinical patients. All enrolled patients also completed the Short Form-36 Health Survey (SF-36) at the baseline visit. Responsiveness to treatment (Venlafaxine and traditional Chinese herbal medicine) was assessed by one-way ANOVA methods. Results The average length of time required to complete the questionnaire was short (5.63 min for IBS patients and 5.54 min for healthy subjects by self-administration). Internal consistency (Cronbach’s alpha) values ranged from 0.722 to 0.914 for the Chinese IBS–QOL subscales and test–retest reliability coefficients were higher than 0.920 on all subscales. The convergent and discriminate validity results comparing the Chinese translation of the IBS–QOL overall score and the SF-36 subscales confirmed our predicted hypotheses. The Chinese IBS–QOL scores are more highly correlated with social functioning, vitality and general health (SF-36) and show weaker associations with physical functioning, role physical, mental health, and bodily pain (SF-36). The Chinese translation of the IBS–QOL was responsive to treatment. Conclusion In general, the Chinese translation of the IBS–QOL, after cultural adaptation and revision, possesses good reliability, validity and responsiveness. It is a reliable and valid instrument to assess the quality of life in Chinese patients suffering from IBS and is an appropriate measure to use in further clinical trials or for related research projects in China.     

Do the SF-36 and WHOQOL-BREF Measure the Same Constructs? Evidence from the Taiwan Population*

Background: The SF-36 and WHOQOL-BREF are available for international use, but it is not clear if they measure the same constructs. We compared the psychometric properties and factor structures of these two instruments. Methods: Data were collected from a national representative sample (n=11,440) in the 2001 Taiwan National Health Interview Survey, which included Taiwan versions of the SF-36 and WHOQOL-BREF. We used Cronbach’s alpha coefficient to estimate scale reliability. We conducted exploratory factor analysis to determine factor structure of the scales, and applied multitrait analysis to evaluate convergent and discriminant validity. We used standardized effect size to compare known-groups validity for health-related variables (including chronic conditions and health care utilization) and self-reported overall quality of life. Structural equation modeling was used to analyze relationships among the two SF-36 component scales (PCS and MCS) and the four WHOQOL subscales (physical, psychological, social relations, and environmental). Results: Cronbach’s alpha coefficients were acceptable (⩾0.7) for all subscales of both instruments. The factor analysis yielded two unique factors: one for the 8 SF-36 subscales and a second for the 4 WHOQOL subscales. Pearson correlations were weak (<0.3) among subscales of both instruments. Correlations for subscales hypothesized to measure similar constructs differed little from those measuring heterogeneous subscales. Effect sizes suggested greater discrimination by the SF-36 for health status and services utilization known groups, but greater discrimination by the WHOQOL for QOL-defined groups. Structural equation modeling suggested that the SF-36 PCS and MCS were weakly associated with WHOQOL. Conclusions: In this Taiwan population sample, the SF-36 and WHOQOL-BREF appear to measure different constructs: the SF-36 measures health-related QOL, while the WHOQOL-BREF measures global QOL. Clinicians and researchers should carefully define their research questions related to patient-reported outcomes before selecting which instrument to use. * Presented in part at (1) 11th Annual Conference of the International Society for Quality of Life Research. Hong Kong, China, 2004. (2) 2004 Quality of Life Symposium – Conceptualization and Measurement issues in QOL. Tai-Chuan, Taiwan, 2004     

Validation of a Risk Factor-Based Intervention Strategy Model Using Data from the Readiness for Return to Work Cohort Study

Background Low back pain (LBP) is a common and in some cases disabling condition. Until recently, workers presenting with non-specific LBP have generally been regarded as a homogeneous population. If this population is not homogeneous, different interventions might be appropriate for different subgroups. We hypothesized that (1) Clusters of individuals could be identified based on risk factors, (2) These clusters would predict duration and recurrences 6 months post-injury. Methods The study focuses on the 442 LBP claimants in the Readiness for Return-to-Work Cohort Study. Claimants (n = 259) who had already returned to work, approximately 1 month post-injury were categorized as the low risk group. A latent class analysis was performed on 183 workers absent from work, categorized as the high risk group. Groups were classified based on: pain, disability, fear avoidance beliefs, physical demands, people-oriented culture and disability management practice at the workplace, and depressive symptoms. Results Three classes were identified; (1) workers with ‘workplace issues’, (2) workers with a ‘no workplace issues, but back pain’, and (3) workers having ‘multiple issues’ (the most negative values on every scale, notably depressive symptoms). Classes 2 and 3 had a similar rate of return to work, both worse than the rate of class 1. Return-to-work status and recurrences at 6 months were similar in all 3 groups. Conclusion This study largely confirms that several subgroups could be identified based on previously defined risk factors as suggested by an earlier theoretical model by Shaw et al. (J Occup Rehab 16(4):591–605, 2006). Different groups of workers might be identified and might benefit from different interventions.     

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.     

Assessment of Readability and Learning of Easy-to-Read Educational Health Materials Designed and Written with the Help of Citizens by Means of Two Non-Alternative Methods

Objectives: We compared two non-alternative methods to assess the readability and learning of easy-to-read educational health materials co-written by physicians, educators and citizens. Methods: Data from seven easy-to-read materials were analyzed. Readability formulae, and ad hoc data on readability and learning were also computed. Results: The respondents had a mean age of 48.5 ± 8.3 (SD) years (range 31–57 years). More than two thirds of them were females. About half of the participants had a ‘secondary’ education or more. According to the readability scores – 54 on average – the booklets resulted to be “easy” for a reader who had received a ‘secondary education’ or more. Of the 747 participants, 70% of them found the booklet’s language to be ‘easy’ or ‘very easy’ and 28% ‘sufficiently easy’ for laypersons to understand. About 98% of the readers found the booklets useful. After reading the booklet 92% (simple knowledge rate) of the readers answered the cognitive items correctly. The after-minus-before net increase in knowledge was 24 ± 16% and ranged from 8 to 40% (cognitive or knowledge delta). Conclusions: The availability of readability scores is complementary and it does not replace the need to assess readability and learning by means of structured and tailored questionnaires.