Validation of the EQ-5D quality of life instrument in patients after myocardial infarction.

Background: We assessed cross-sectional validity of EQ-5D after myocardial infarction (MI). Methods: We compared EQ-5D, SF-36, quality of life After MI (QLMI), and Canadian Cardiovascular Society Anginal Classification (CCSG) scores. Correlation and regression techniques were used to assess convergent validity. SF-36 and alternate Rand-36 scoring were compared. CCSG class was used to evaluate discriminative validity and clinical difference in health state scores. Results: Of 99 patients: mean age 64; median 176.5 days post-MI; 80% had one MI; 74% were CCSG I. 1/3 to 1/2 reported mobility, self-care, pain, and emotional difficulties on EQ-5D. Median health state was 0.73. EQ-5D and SF-36 (or Rand-36) strongly correlate in overall health (0.75), emotional health (0.75), pain (0.68), and activity/ functional (0.5–0.63). EQ-5D and QLMI strongly correlate in activities/ self esteem (0.56), emotional health (0.64), anxiety/depression – restriction (0.53), and overall health (0.5–0.57). EQ-5D self-care correlates weakly with all domains. Domain scores from each general instrument contributed to each other’s overall health score (adjusted R2 0.61–0.69) and to disease specific score (0.45 adjusted R2). EQ-5D discriminates among CCSG classes (p < 0.000). Physicians detected a 0.16 difference in health state scores. Conclusion: The EQ-5D provides valid general HrQOL measurement post-MI.