Validity and reliability of three commonly used quality of life measures in a large European population of coronary heart disease patients

Objective: To investigate the validity and reliability of the EuroQol-5D (EQ-5D), the 12-item Short-Form Health Survey (SF-12v2), and the Hospital Anxiety and Depression Scale (HADS) in a stable coronary population.

Study design: Cross-sectional study EUROASPIRE III.

Setting: Quality of life data (QoL) were available on 8745 patients hospitalized for coronary artery bypass graft (CABG), percutaneous coronary intervention (PCI), acute myocardial infarction (AMI), or myocardial ischemia. They were interviewed and examined at least 6 months after their hospital admission. Reliability and validity of the 3 instruments were tested. Internal consistency, and discriminative, convergent, criterion and construct validity were assessed.

Results: Cronbach's alpha indicated good internal consistency for all measures (0.73 to 0.87). Discriminative validity analyses confirmed significant QoL differences between known groups: age, gender, educational level. In addition, all hypothesized correlations between QoL constructs (convergent validity) and items (criterion validity) were confirmed with significant correlations. Confirmatory factor analyses indicated good construct validity for HADS and SF-12v2. On country-specific level, results were roughly similar.

Conclusion: The EQ-5D as well as the SF-12v2 and the HADS are reliable and valid instruments for use in a stable coronary population, both on aggregate European level and on country-specific level. However, our results must be generalized with caution, because EUROASPIRE III patients might not be representative for all patients with stable coronary heart disease.