Cardiovascular drug use prior to diagnosis of diabetes: a pilot study in community pharmacy.

Objectives: The literature indicates that cardiovascular drug use is higher during the years prior to diagnosis of type 2 diabetes mellitus. As there are pharmaco-epidemiological and economic consequences of enhanced medication use prior to diagnosis of diabetes, there is a need for a comparative analysis of the drug-use pattern by patients with a subsequent diagnosis of diabetes and control patients. This pilot study aimed to investigate cardiovascular drug use in patients with a subsequent diagnosis of diabetes using data extracted from 200 community pharmacies in the Belgian township of Hasselt.

Methods: Based on community pharmacy data, a retrospective case-control study compared the drug use of patients with a subsequent diagnosis of type 2 diabetes (cases) with patients without a subsequent diagnosis (controls). Cases were identified if patients started taking metformin (and possibly other drugs used in diabetes) during the 2004-2006 study period. Drug use was expressed as a binary variable, reflecting whether or not a patient took drugs belonging to a specific cardiovascular subclass.

Key Findings: Our dataset consisted of 158 cases with a subsequent diagnosis of type 2 diabetes and 632 control patients. Patients with a subsequent diagnosis of type 2 diabetes had a higher propensity to take cardiovascular drugs prior to diagnosis than control patients. This trend was observed across all cardiovascular drug classes, except for calcium-channel blockers, and was statistically significant for beta-blocking agents and agents acting on the renin-angiotensin system.

Conclusions: A positive association was observed between cardiovascular drug use and subsequent diagnosis of type 2 diabetes. This study emphasizes the potential role for community pharmacy in early identification of diabetes using more targeted screening based on cardiovascular drug use as derived from pharmacy databases.