Validation of the EQ‐5D in patients with a history of acute coronary syndrome

Abstract

Objective: To analyze the construct validity of the EQ‐5D in patients with acute coronary syndromes (ACS). Methods: All ACS-diagnosed patients discharged from a university-affiliated hospital during a 3‐year period were mailed a questionnaire that included the EQ‐5D and the SF‐8. The EQ‐5D includes a visual analogue scale (EQ VAS) to measure self-reported current health-status (0–100) and a five-item descriptive system measuring mobility, self-care, usual activities, pain/discomfort, and anxiety/depression. Also included were disease severity measures [Duke Activity Status Index (DASI), cardiac symptom count (SC), patient-perceived cardiac disease severity], comorbidity measures (Charlson comorbidity index, total medication count), and other demographic and disease-related items. Results: Of 1217 patients, 490 (40.3%) responded. Patients averaged 65.2 (SD 11.3) years of age; 71.0% male; 91.9% Caucasian; 64.3% history of MI. Only 0.2%–0.4% of EQ‐5D items and 8% of the EQ VAS were left unanswered by respondents. The nine most common health states were identified based on the five EQ‐5D item scores. Levels of responses to EQ‐5D items and the EQ VAS score were significantly better for patients with very mild/mild perceived disease severity compared to severe/very severe, for patients with lower comorbidity, for patients with lower symptom responses, and for patients with a higher cardiac-related functioning. EQ VAS score and SF‐8 subscale score correlation coefficients ranged from 0.527 to 0.798 (all p < 0.0001). Significant differences were observed between the response level of individual EQ‐5D items and scores of comparable SF‐8 subscales. Conclusions: This study demonstrated the construct validity of the EQ‐5D in a population-based sample of patients with a history of ACS.