How to best assess quality of drug treatment in patients with heart failure.

Background: The proportion of patients with heart failure (HF) treated with angiotensin-converting enzyme inhibitors (ACEI) or angiotensin receptor blockers (ARB) is frequently used as quality indicator. This study aimed to compare agreement between different methods of calculating this quality indicator. In addition, characteristics for patients and care providers associated with a high proportion treated with ACEI or ARB were analyzed.

Methods: This Swedish cross-sectional register-based study was conducted in the Stockholm region (2.1 million inhabitants). The proportion of patients with HF treated with ACEI or ARB was calculated by different methods applied on an administrative database on healthcare consumption, diagnoses, and dispensed drugs and by self-reported data from all primary care centers in the region.

Results: A total of 32,677 patients recorded with a HF diagnosis 2008-2012 and alive July-December 2012 were identified. The proportion treated with ACEI or ARB varied depending on observation period and care provider included (range register 52-74 %). There was a large variation between different primary care centers (range register 36-88 %, range self-reported 8-100 %) and a poor agreement between methods (Bland-Altman; rhoc range 0.07-0.23). Predictors for high proportion treated were low age, high socioeconomic status, cardiovascular comorbidity, and diagnosis recorded both in primary care and in hospitals.

Conclusions: There is poor agreement between different methods to evaluate adherence to guidelines for drug treatment in HF. Differences between practices concerning patient age, socioeconomic status, comorbidity, and care given by different providers should be taken into account in quality assessment.