Misdiagnosis and mistreatment of ACE-inhibitor-induced cough occurs frequently and decreases therapy compliance

Abstract

OBJECTIVE: A common side-effect of angiotensin-converting enzyme inhibitors (ACEi) is a persistent dry cough. Physicians and pharmacists who fail to recognise a dry cough to be ACEi-related may attempt to treat it with antitussives, instead of recommended ACEi substitution. The aim of this study was to quantify such prescription behaviour, as well as its influence on therapy compliance. DESIGN AND METHODS: Drug dispensing data were retrieved from the IADB.nl database in The Netherlands. A prescription sequence symmetry analysis was used to determine whether antitussive agents were prescribed more often following ACEi initiation than the other way around. Therapy compliance in both groups was assessed using the proportion of days covered (PDC) method; patients with a PDC ≥ 80% were considered compliant. RESULTS: 1601 patients were incident users of both ACEi and antitussives within a half-year time span. There was a significant excess of patients prescribed antitussive agents after ACEi initiation (1075 versus 526), yielding a sequence ratio of 2.0 (95% confidence interval 1.8-2.3). Therapy compliance in patients receiving antitussives after ACEi initiation was 58%, significantly lower than therapy compliance in control patients, which was 77% (