Cardiovascular risk factors and diseases precede oral hypoglycaemic therapy in patients with type 2 diabetes mellitus☆

Abstract 

Although patients with type 2 diabetes mellitus and cardiovascular disease share common risk factors, the link between these diseases remains largely unexplained. In this case-control study, the earlier use of cardiovascular drugs (before the diagnosis of diabetes) was investigated among cases with type 2 diabetes mellitus and controls without diabetes. Using the PHARMO database, we identified 4,864 patients who were prescribed oral hypoglycaemic agent (OHA) therapy between 1985–1998 in the Netherlands. For each case, two controls matched on age, sex and pharmacy were randomly selected. Controls had not received insulins or OHA therapy. There were 2,656 (55.0%) cases compared with 2,727 (28.1%) controls who used cardiovascular drugs at the start of OHA therapy. Cases had a 3.5-fold increased risk of cardiovascular drug use (OR_{95% CI} = 3.5 [3.2–3.8]) compared to controls. Differences in cardiovascular drug use were noted as early as 7 years before the start of OHA therapy, distinguishing cases from controls. Our finding that patients with type 2 diabetes mellitus were more likely to receive treatment for cardiovascular disease several years before they start diabetes therapy supports the hypothesis of a common underlying mechanism of these two disorders and stresses the importance of the pre-diabetic state.

Keywords: diabetes mellitus, cardiovascular drugs, case-control study, epidemiology, prevalence