Conversion of the Seattle Angina Questionnaire into EQ-5D utilities for ischemic heart disease: a systematic review and catalog of the literature

BACKGROUND: There is a paucity of preference-based (utility) measures of health-related quality of life for patients with ischemic heart disease (IHD); in contrast, the Seattle Angina Questionnaire (SAQ) is a widely used descriptive measure. Our objective was to perform a systematic review of the literature to identify IHD studies reporting SAQ scores in order to apply a mapping algorithm to convert these to preference-based scores for secondary use in economic evaluations. METHODS: Relevant articles were identified in MEDLINE (Ovid), EMBASE (Ovid), Cochrane Library (Wiley), HealthStar (Ovid), and PubMed from inception to 2012. We previously developed and validated a mapping algorithm that converts SAQ descriptive scores to European Quality of Life-5 Dimensions (EQ-5D) utility scores. In the current study, this mapping algorithm was used to estimate EQ-5D utility scores from SAQ scores. RESULTS: Thirty-six studies met the inclusion criteria. The studies were categorized into three groups, ie, general IHD (n=13), acute coronary syndromes (n=4), and revascularization (n=19). EQ-5D scores for patients with general IHD were in the range of 0.605–0.843 at baseline, and increased to 0.649–0.877 post follow-up. EQ-5D scores for studies of patients with recent acute coronary syndromes increased from 0.706–0.796 at baseline to 0.795–0.942 post follow-up. The revascularization studies had EQ-5D scores in the range of 0.616–0.790 at baseline, and increased to 0.653–0.928 after treatment; studies that focused only on coronary artery bypass grafting increased from 0.643–0.788 at baseline to 0.653–0.928 after grafting, and studies that focused only on percutaneous coronary intervention increased in score from 0.616–0.790 at baseline to 0.668–0.897 after treatment. CONCLUSION: In this review, we provide a catalog of estimated health utility scores across a wide range of disease severity and following various interventions in patients with IHD. Our catalog of EQ-5D scores can be used in IHD-related economic evaluations.