Comparison of the EQ-5D and SF-12 health surveys in a general population survey in Alberta, Canada.
OBJECTIVE
The purposes of this analysis were to evaluate the construct validity of the EQ-5D and compare responses on the EQ-5D with the Physical Component Summary (PCS-12) and Mental Component Summary (MCS-12) scores of the SF-12 Health Survey.


METHODS
Data were collected via a survey instrument mailed to 4,200 randomly selected subjects in the province of Alberta, Canada. The instrument contained the EQ-5D and SF-12 health surveys, with additional questions eliciting clinical and demographic information from the respondents.


RESULTS
1,555 respondents returned mailed questionnaires; 606 questionnaires were returned undeliverable. The SF-12 summary scores were calculated for 1,380 respondents. Analysis of the EQ-5D responses by demographic variables found significant differences among categories of age, gender, and self-reported chronic medical conditions. Corresponding dimensions and summary scores were more strongly related (eg, mobility and PCS-12; F ratio = 598.3, P < 0.001) than dissimilar dimensions (eg, mobility and MCS-12; F ratio = 18.8, P < 0.001). The EQ-5D index scores were moderately correlated with SF-12 summary scores (r = 0.41 for MCS-12 and r = 0.68 for PCS-12). For subjects reporting no problems on the EQ-5D, PCS-12 and MCS-12 scores were significantly lower for people reporting medical problems or feelings of depression.


CONCLUSIONS
The results of this investigation generally supported the validity of the EQ-5D. However, an important ceiling effect was observed for the EQ-5D in this sample. The combination of the EQ-5D and SF-12 provides relatively broad coverage of important health domains and scores for various purposes.
Johnson
J A
JA
Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, and the Institute of Health Economics, Edmonton, Canada.
Pickard
A S
AS
D000203:Activities of Daily Living; D000328:Adult; D000368:Aged; D000416:Alberta / Q000453:epidemiology; D003430:Cross-Sectional Studies; D005260:Female; D006304:Health Status; D006306:Health Surveys; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008603:Mental Health; D008875:Middle Aged; D011159:Population Surveillance / Q000379:methods; D015203:Reproducibility of Results; D012959:Socioeconomic Factors; D011795:Surveys and Questionnaires / Q000592:standards*