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.     

Comparing self-reported health status and diagnosis-based risk adjustment to predict 1- and 2 to 5-year mortality

OBJECTIVES: To compare the ability of two diagnosis-based risk adjustment systems and health self-report to predict short- and long-term mortality. DATA SOURCES/STUDY SETTING: Data were obtained from the Department of Veterans Affairs (VA) administrative databases. The study population was 78,164 VA beneficiaries at eight medical centers during fiscal year (FY) 1998, 35,337 of whom completed an 36-Item Short Form Health Survey for veterans (SF-36V) survey. STUDY DESIGN: We tested the ability of Diagnostic Cost Groups (DCGs), Adjusted Clinical Groups (ACGs), SF-36V Physical Component score (PCS) and Mental Component Score (MCS), and eight SF-36V scales to predict 1- and 2-5 year all-cause mortality. The additional predictive value of adding PCS and MCS to ACGs and DCGs was also evaluated. Logistic regression models were compared using Akaike's information criterion, the c-statistic, and the Hosmer-Lemeshow test. PRINCIPAL FINDINGS: The c-statistics for the eight scales combined with age and gender were 0.766 for 1-year mortality and 0.771 for 2-5-year mortality. For DCGs with age and gender the c-statistics for 1- and 2-5-year mortality were 0.778 and 0.771, respectively. Adding PCS and MCS to the DCG model increased the c-statistics to 0.798 for 1-year and 0.784 for 2-5-year mortality. CONCLUSIONS: The DCG model showed slightly better performance than the eight-scale model in predicting 1-year mortality, but the two models showed similar performance for 2-5-year mortality. Health self-report may add health risk information in addition to age, gender, and diagnosis for predicting longer-term mortality.     

Assessment of Reliability and Validity of SF-12v2 among a Diabetic Population

Objectives

To validate the Medical Outcomes Study Short Form version 2 (SF-12v2) in diabetic patients.

Use of the Short Form-36 to Detect the Influence of Upper Gastrointestinal Disease on Self-Reported Health Status

Patient-centred outcome measures such as the Short Form-36 (SF-36) have been developed to assess the impact of ill health and medical interventions on self-reported health status. The objective of the study was to assess the impact of gastrointestinal disease upon health status as measured by the SF-36 physical and mental health component scores (PCS and MCS) and to assess whether these component scores might be an appropriate outcome measure for use in clinical research in gastroenterology. The subjects were 364 patients aged between 18 and 64 years who had been prescribed proton pump inhibitors (PPIs) by general practitioners in Oxfordshire. The general practices participating identified patients who had been prescribed PPIs. The data were abstracted from the general practice medical records of these patients concerning gastrointestinal diagnoses and other prescribed medications. The patients were sent the SF-36 questionnaire by post and the PCS and MCS scores were derived, which were adjusted for age and sex and compared with the scores of the general population of the Oxford region. Co-morbidity was assessed by the extent to which non-gastric medications were also used. The commonest diagnoses were oesophagitis/gastro-oesophageal reflux and indigestion. People with these diagnoses had significantly lower health status than the general population. Differences persisted when the results were controlled for the possible effects of co-morbidity. It was concluded that the SF-36 is sensitive to the impact of gastrointestinal disease on health status. This revised version was published online in June 2006 with corrections to the Cover Date.     

Health-related quality of life in patients with interstitial cystitis/bladder pain syndrome and frequently associated comorbidities

Purpose

To estimate the association of chronic non-urologic conditions [i.e., fibromyalgia (FM), chronic fatigue syndrome (CFS), and irritable bowel syndrome (IBS)] with health-related quality of life (HRQOL) in patients with interstitial cystitis/bladder pain syndrome (IC/BPS).

Methods

A total of 276 women with established diagnoses of IC/BPS completed a telephone interview which included demographics, self-reported medical conditions, the SF-36 health survey, and the interstitial cystitis symptom index (ICSI). Multivariate linear regression analysis was used to identify correlates of SF-36 physical and mental component summary scores.

Results

Mean patient age was 45.1 (SD 15.9) years, and 83 % of the subjects were white. Mean values for the SF-36 Physical Component Score (PCS) and Mental Component Score (MCS) means were 39 (SD 14) and 45 (SD 12), respectively, indicating significant HRQOL reductions. Mean ICSI score was 11.27 (SD = 4.86). FM and IBS were significantly associated with worse SF-36 scores: ?8 points on the PCS (p < 0.001) and ?6 points on the MCS (p < 0.001). CFS and the presence of other pelvic conditions (overactive bladder, vulvodynia, endometriosis) were not significantly associated with SF-36 PCS and MCS scores.

Conclusions

In patients with IC/BPS, the presence of FM, CFS, and IBS has a significant association with HRQOL, equivalent in impact to the bladder symptoms themselves. These results emphasize the importance of a multidisciplinary approach to treating patients with IC/BPS and other conditions.     

How should we evaluate health status? A comparison of three methods in patients presenting with obstructive sleep apnoea

The purpose of this paper is to compare three approaches to the measurement of patient-reported health status which produce summary scales of health status: the Patient-generated Index (PGI) is a measure of individual quality of life (QoL), the EuroQol is a measure of QoL the results of which are weighted by utility values gained from community surveys and the SF-36 which produces two summary scales of health status (the physical component summary (PCS) and the mental component summary (MCS) scores). A follow-up interview survey of patients with obstructive sleep apnoea (OSA) was conducted. The patients received continuous positive airways pressure therapy (CPAP) between the two administrations of the questionnaires. One hundred patients presenting with OSA and who were suitable for CPAP therapy were asked if they would take part in the study. The results on the PGI, EuroQol EQ-5D utility weighted scores and thermometer scores and SF-36 physical and mental summary scores were measured. Eighty-nine respondents provided sufficient data to calculate PGI and EuroQol scores and 86 patients provided sufficient data to calculate SF-36 summary scores. The PGI indicated substantial improvement after CPAP treatment whereas the EuroQol indicated little or no improvement on either utility weighted or thermometer scores. The SF-36 PCS and MCS scores were lower than those of the general population at baseline, but had improved to the normative levels after treatment. The EuroQol provided a substantially different picture of change to either of the ones gained from the SF-36 or PGI. It is suggested that the EuroQol does not contain questions which relate to important aspects of health and well-being and may not accurately reflect the health state of individuals. Consequently, caution must be exercised to assure that an appropriate instrument has been employed when using health outcomes data to assess or prioritize available health care treatments.     

The impact of chronic hepatitis C and co-morbid illnesses on health-related quality of life

OBJECTIVES: Determine the relative impact of chronic hepatitis C (CHC) and co-morbid illnesses on health-related quality of life (HRQoL) in 3023 randomly selected veterans with known hepatitis C virus antibody (anti-HCV) status who previously completed a veteran-specific HRQoL questionnaire (SF-36V). METHODS: Multiple regression analyses were performed to measure the relative contribution of anti-HCV status, four demographic variables, and ten common medical and six psychiatric co-morbidities to HRQoL between 303 anti-HCV(+) and 2720 anti-HCV(-) patients. RESULTS: Anti-HCV(+) veterans were younger, reported a lower HRQoL on seven of eight 36-Item Short Form Health Survey for Veterans (SF-36V) subscales (P < or = 0.001) and the mental component summary (MCS) scale (P < 0.001). The ten medical and six psychiatric co-morbidities had variable impact on predicting lower HRQoL in both groups. After adjusting for demographic variables and co-morbid illnesses, we found that anti-HCV(+) patients reported a significantly lower MCS score (P < 0.001) and a trend toward a lower physical component summary (PCS) score (P < 0.07) compared to anti-HCV(-) veterans. Among the anti-HCV(+) veterans, co-morbid medical illnesses contributed to impaired PCS but not to MCS. CONCLUSIONS : Veterans with CHC were younger than HCV(-) veterans and hence less likely to have other co-morbid medical illnesses. Medical co-morbidities seen in those veterans with CHC contribute to impaired PCS but not MCS. Anti-HCV(+) status negatively affects HRQoL, particularly MCS, independently of medical and psychiatric co-morbidities.     

International SF-36 reference values in patients with ischemic heart disease

Purpose

International reference data for the SF-36 health survey (version 1) are presented based on a sample of 5508 adult patients with ischemic heart disease.

Methods

Patients with angina, myocardial infarction and ischemic heart failure completed the SF-36. Data were analyzed by diagnosis, gender, age, region and country within region and presented as mean ± standard deviation (SD), minimum, maximum, 25th, 50th and 75th percentile of the physical (PCS) and mental component summary (MCS) measures.

Results

Mean PCS scores were reported as being more than one SD below the normal range (standardized mean of 50 ± 10) by more than half of the patient subgroups (59 %) with all of the mean MCS scores falling within the normal range. Patients with angina and patients with ischemic heart failure reported the poorest mean PCS scores with both diagnoses reporting scores more than one SD below the standardized mean. Females, older patients (especially >70 years) and patients from Eastern Europe reported significantly worse mean PCS scores than male, younger and non-Eastern European patients. The cardiac diagnosis had no effect on the mean MCS scores; however, females, younger patients (especially <51 years) and patients from Eastern Europe reported significantly worse mean MCS scores than male, older and non-Eastern European patients.

Conclusions

These international reference SF-36 values for patients with IHD are useful for clinicians, researchers and health-policy makers when developing improved health services.

     

Use of the SF-12 instrument for measuring the health of homeless persons

OBJECTIVE: To evaluate the construct validity of the Short Form 12-item Survey (SF-12) among users of a homeless day shelter. Adding brief health assessments has potential to provide information regarding the effect that programs have upon the health status and functioning of homeless persons. STUDY SETTING: A convenience sample of 145 homeless persons at a day shelter in an urban setting. STUDY DESIGN: Participants were verbally administered the SF-12 that provides information on mental and physical health status and the Dartmouth Improve Your Medical Care Survey (IYMC) that provides information on functional health, clinical symptoms, medical conditions, and health risk. The IYMC survey system has been widely used in clinical settings to assess health status and the outcomes of care. DATA COLLECTION/EXTRACTION METHODS: Construct validity was assessed by the following approaches: (a) the method of extreme groups was used where multivariate analysis of variance determined if SF-12 summary scores varied for individuals who differed in self-reported clinical symptoms and medical conditions, and (b) convergent validity was assessed by correlating SF-12 summary scores with the subscales. PRINCIPAL FINDINGS: Four to 10 point differences in physical health (PCS12) and 5-11 point differences in mental health (MCS12) were found between those who reported acute symptoms and medical conditions and those who did not. A 13-point difference in PCS12 scores and a 7-16-point difference in MCS12 scores were found for those who reported none or few to several symptoms or conditions. The summary scores and subscales yielded satisfactory convergent validity coefficients that ranged from 0.62 to 0.88 with one exception. CONCLUSIONS: The SF-12 shows promise as a valid outcome indicator for assessing and monitoring health status among the homeless. Its strengths include brevity and availability of norms for specific medical conditions.     

Results from several population studies show that recommended scoring methods of the SF-36 and the SF-12 may lead to incorrect conclusions and subsequent health decisions

Purpose

To compare the measurement properties of the physical component summary (PCS) and mental component summary (MCS) scores of the SF-36 and SF-12 based on the traditional orthogonal scoring algorithms with the performance of the PCS and MCS scored based on structural equation model coefficients from a correlated model.

Methods

This study used three large-scale representative population studies to compare the measurement properties of the PCS and MCS scores of the SF-36 and SF-12 with the performance of the PCS and MCS scores based on structural equation models producing coefficients from a correlated model. We assessed the relationships of these scores with selected important mental health measures and chronic conditions from three representative Australian population studies that address clinical conditions of high prevalence and health service importance.

Results

Structural equation model scoring methods produced summary scores with higher correlations than the recommended orthogonal methods across a range of disease and health conditions. The problem experienced in using the orthogonal methods is that negative scoring coefficients are applied to negative z-scores for sub-scales, inflating the resulting summary scores. Effect sizes over a half of a standard deviation were common.

Conclusions

If health policy or investment decisions are made based on the results of studies employing the recommended orthogonal scoring methods then the expected outcome of such decisions or investments may not be achieved.     

Health-related quality of life and comorbidity among older women veterans in the United States

Purpose

This paper examines the predictors of quality of life among older women (≥65 years of age) veterans in the United States focusing on the effect of comorbidity on health-related quality of life (HRQOL).

Methods

Data from the National Survey of Women Veterans, a cross-sectional nationally representative population-based, stratified random sample of women veterans, were used with an analytic sample size of 1,379 older women veterans. The SF12 physical and mental composite scores (PCS and MCS) were used as outcome measures, and a weighted comorbidity index was used as a covariate.

Results

Older women veterans who are married, employed, with higher income, and higher education have better physical health (PCS). For mental health, education is positively correlated, whereas depression and posttraumatic stress disorder are negatively correlated with MCS. After adjusting for socio-demographic, mental health, and chronic health indicators, the results showed that SF12 PCS varied by VA use status for each level of Seattle Index of Comorbidity. The same pattern was not found for MCS.

Conclusion

For each level of comorbidity, VA users have worse HRQOL which might suggest that case mix adjustments comparing VA users and non-VA users must take into account more than comorbidity alone.     

Validation testing of a three-component model of Short Form-36 scores

Objective

The two-component factor structure underlying Short Form-36 (SF-36) summary scores may not be valid worldwide. We studied a three-component model of SF-36 scores in Japan.

Study Design and Setting

The SF-36 scores came from representative samples of the population of Japan. Factor analysis and structural equation modeling were used. The two-component model gave physical component summary (PCS) scores and mental component summary (MCS) scores. The three-component model gave scores on the PCS, the MCS, and also on the third component, which we call the role component summary (RCS) score. These were evaluated with external criteria.

Results

In the three-component model, the RCS was strongly associated with the role-physical, social functioning, and role-emotional subscales, whereas the PCS and MCS were associated with the physical functioning and mental health subscales, as expected. The goodness-of-fit index was 0.945 for the three-component model and 0.935 for the two-component model. The PCS discriminated between groups stratified by comorbid conditions, and the MCS discriminated between groups stratified by psychological depression. Absence from work was associated with both PCS and RCS.

Conclusion

The three-component model is better than the two-component model, and it provides more useful PCS and MCS scores. Criteria for validation testing of the RCS are needed.     

Health-related quality of life in HIV-1-infected patients on HAART: a five-years longitudinal analysis accounting for dropout in the APROCO-COPILOTE cohort (ANRS CO-8)

BACKGROUND: The long-term efficacy of Highly Active Antiretroviral Therapies (HAART) has enlightened the crucial role of health-related quality of life (HRQL) among HIV-infected patients. However, any analysis of such extensive longitudinal data necessitates a suitable handling of dropout which may correlate with patients' health status. METHODS: We analysed the HRQL evolution over 5 years for 1,000 patients initiating a protease inhibitor (PI)-containing therapy, using MOS SF-36 physical (PCS) and mental (MCS) scores. In parallel with a classical separate random effects model, we used a joint parameter-dependent selection model to account for non-ignorable dropout. RESULTS: HRQL evolved according to a two-phase pattern, characterized by an initial improvement during the year following HAART initiation and a relative stabilization thereafter. Immunodepression and self-reported side effects were found to be negative predictors of both PCS and MCS scores. Hepatitis C virus coinfection and AIDS clinical stage were found to affect physical HRQL. Results were not significantly altered when accounting for dropout. CONCLUSION: Such results, obtained on a large sample of HIV-infected patients with extensive follow-up, underline the need for a regular monitoring of patients' immunological status and for a better management of their experience with hepatitis C and HAART.     

A comparison of SF-36 summary measures of physical and mental health for women across the life course

Background

Physical and mental component summary scores (PCS and MCS, respectively) are often used to summarise SF-36 quality of life subscales. This paper investigates PCS and MCS across the life course and compares the trajectories obtained from two different methods of calculation.

Methods

The Australian Longitudinal Study on Women’s Health is a population-based study with three cohorts of women and SF-36 surveys taken at multiple time points. Scoring coefficients for each component score were determined using factor analysis with uncorrelated (orthogonal) and correlated (oblique) rotation at the baseline survey, which were then used to compute correlated and uncorrelated PCS and MCS scores at each survey (scaled to have mean of 50 and standard deviation of 10 at baseline).

Results

For both methods, PCS declined progressively across the lifespan, while MCS rose in young and mid-age women to a peak and subsequently declined in later life. Differences were apparent between correlated and uncorrelated scores, most notably for MCS in the older cohort, where correlated MCS reached 54.6 but still less than uncorrelated MCS, with a random effects model indicating 1.63 (95 % confidence intervals 1.58–1.67) units difference; it then declined to a score of 51.2 by the last survey and the difference widened to 3.44 (3.38–3.50) units compared with the uncorrelated MCS.

Conclusions

PCS and MCS have distinct trajectories through life, with differences in results from correlated and uncorrelated component summary scores. The divergence is most notable with MCS, especially for older women, suggesting that correlated MCS and PCS should be used when examining change in health over time in this age group.     

Association of patient demographics on quality of life in a sample of adult patients with cardiac arrhythmias

Purpose

Identify predictors of quality of life (QOL) in patients with any form of cardiac arrhythmia (CA).

Methods

Data from the Medical Panel Expenditure Survey were analyzed from 2004 to 2009. Patients aged ≥18 with any form of CA (identified via ICD-9-CM codes) were included. Primary outcomes included the physical and mental component scores (PCS and MCS) of the Short-Form 12 version 2 (SF-12) and EuroQoL-5D (EQ-5D) utility scores (US version). Patient demographics included insurance status, urban status, geographical region, federal poverty level, education, comorbidities, and disease-related risk factors of CA.

Results

Approximately 5,750,440 individuals had CA. Non-Hispanic Whites had the highest SF-12 MCS (mean 50.9; p < 0.001 across racial groups) and utility scores (mean 0.76; p < 0.001 across racial groups). Patients with both private and public insurance had significantly higher PCS (p = 0.001) and MCS (p < 0.001) in comparison with patients only covered by public insurance. Patients on antiarrhythmic agents had higher SF-12 MCS (51.4 vs. 48.4; p < 0.001) compared to individuals not on antiarrhythmic agents.

Conclusions

Significantly lower QOL existed in specific subpopulations (e.g., patients with only public health insurance, racial/ethnic minorities, and those not exposed to antiarrhythmic agents) within the CA population.     

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.     

Smoking and functional status among Medicare managed care enrollees

BACKGROUND: Smoking is a major determinant of health status and outcomes. Current smoking has been associated with lower scores on the Short Form-36 Health Survey (SF-36). Whether this occurs among the elderly and disabled Medicare populations is not known. This study assessed the relationships between smoking status and both physical and mental functioning in the Medicare managed-care population. METHODS: During the spring of 1998, data were collected from 134309 elderly and 8640 disabled Medicare beneficiaries for Cohort 1, Round 1 of the Medicare Health Outcomes Survey. We subsequently used these data to calculate mean standardized SF-36 scores, self-reported health status, and prevalence of smoking-related illness, by smoking status, after adjusting for demographic factors. RESULTS: Among the disabled, everyday and someday smokers had lower standardized physical component (PCS) and mental component (MCS) scores than never smokers (-2.4 to -4.5 points; p <0.01 for all). Among the elderly, the lowest PCS and MCS scores were seen among recent quitters (-5.1 and -3.7 points, respectively, below those for never smokers; p <0.01 for both), but current smokers also had significantly lower scores on both scales. For the elderly and disabled populations, MCS scores of long-term quitters were the same as nonsmokers. Similar patterns were seen across all eight SF-36 scales. Ever smokers had higher odds of reporting both less-than-good health and a history of smoking-related chronic disease. CONCLUSIONS: In the elderly and disabled Medicare populations, smokers report worse physical and mental functional status than never smokers. Long-term quitters have better functional status than those who still smoke. More effort should be directed at helping elderly smokers to quit earlier. Smoking cessation has implications for improving both survival and functional status.     

Estimation of non-response bias in the Medicare FFS HOS

We examined non-response bias in physical component summary scores (PCS) and mental component summary scores (MCS) in the Medicare fee-for-service (FFS) Health Outcomes Survey (HOS) using two alternative methods, response propensity weighting and imputation for non-respondents. The two approaches gave nearly identical estimates of non-response bias. PCS scores were 0.74 points lower and MCS scores 0.51 points lower after adjustment for non-response through imputation and 0.63 and 0.46 lower after adjustment for propensity weighting. These levels are small for component scores suggesting that survey non-response to the FFS HOS does not adversely affect estimates of average health status for this population.     

Rural-Urban Disparities in Health-Related Quality of Life Within Disease Categories of Veterans

ABSTRACT:  Context: Compared to their urban counterparts, rural veterans have been found to have lower health-related quality of life. Purpose: To determine whether these disparities persist when examining disease categories of rural and urban veterans. Methods: We obtained survey data on 748,216 veterans who were current or anticipated Veterans Health Administration patients. Using International Classification of Diseases (ICD)-9CM codes, we determined whether these veterans had diagnoses that fell into any of 30 physical health disease categories, and we used ZIP codes to determine whether veterans lived in rural or urban settings. We compared rural to urban prevalence of disease categories as well as urban to rural health-related quality-of-life physical health component summary scores (PCS) and mental health component summary scores (MCS) for each disease category. Findings: Physical diagnoses were significantly more prevalent in the rural veteran population for most disease categories examined. For every disease category examined, PCS were significantly lower for veterans who lived in rural, compared to urban, settings ( P < .001 for all); rural veterans also experienced lower MCS for all disease categories although differences were modest. Differences persisted after controlling for sociodemographic factors. Conclusions: Compared to the urban veteran population, within disease categories, the rural veteran population experiences higher disease prevalence and lower physical and mental quality-of-life scores. Policymakers should anticipate greater health care demands from the rural veteran population and work to meet that demand.     

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.