Reduced vascular events in type 2 diabetes by biguanide relative to sulfonylurea: study in a Japanese Hospital Database

BACKGROUND: Some oral hypoglycemic agents (OHAs) have been suggested to reduce the risk of cardiovascular disease (CVD) in type-2 diabetes mellitus (T2DM). We ascertained if OHAs affect CVD risk in a cohort analysis of a multicenter medical-cost accounting database in Japan. METHODS: Data of 4095 and 1273 T2DM patients in study 1 and study 2, respectively, were extracted from the database based on the following conditions: (i) began treatment with a single OHA (sulfonylurea, biguanide, thiazolidinedione, α-glucosidase inhibitor, glinide, or dipeptidyl peptidase-4 inhibitor) and continued the medication for ~1–1.4 years; (ii) hemoglobin (Hb)A1c level at baseline was available; (iii) age at baseline was 40–70 years; (iv) presence or absence of CVD history was not considered in study 1, but presence of CVD history was considered in study 2. Effects of OHAs relative to sulfonylurea on CVD risk according to ICD-10 were analysed using Kaplan-Meier curves during 104 weeks. RESULTS: In study 1 targeting T2DM patients with and without a history of CVD, initial and baseline treatment with a biguanide significantly lowered the risk of CVD compared with that with a sulfonylurea, and was independent of HbA1c control. In study 2, a similar significant preventive effect of a biguanide on CVD risk relative to a sulfonylurea was observed in T2DM patients with history of CVD. CONCLUSIONS: Initial treatment and baseline treatment with a biguanide can reduce CVD risk relative to a sulfonylurea independent of the blood glucose-lowering effect of the biguanide in Japanese T2DM patients. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12902-015-0045-y) contains supplementary material, which is available to authorized users.