A case-control study on long term insulin therapy and its relation with cardiovascular complications in type 2 diabetes (T2DM) mellitus patients

Backgrounds: Long-term insulin treatment is becoming more and more common in type 2 diabetes mellitus (T2DM) patients, although the relationship of it with cardiovascular events and metabolic abnormalities are still undetermined. Objectives: The purpose of this case-control study was to investigate the associations between long-duration insulin treatment and cardiovascular disease, metabolic aspects and diabetes-related complications among subjects with T2DM. Methods: We performed a case-control study comparing 250 patients with insulin-treated T2DM (cases) who received ≥5 consecutive years of insulin treatment to 250 matched non-insulin treated T2DM patients (controls), using only oral antidiabetic agents. They were frequency-matched according to age, sex, disease duration and baseline HbA1c. The primary outcomes were major adverse cardiovascular events (MACE), cardiovascular mortality, and microvascular complications. Secondary measures included changes in body weight, lipid profile and glycemic control parameters. Results: MACE (18.4% vs 12.1%, p=0.032) and cardiovascular mortality (6.8% vs 3.2%, p=0.018) were significantly higher in groups treated with insulin than in non-insulin-treated controls. Rates of severe hypoglycemic episodes were substantially higher in the insulin group (12.4% vs 2.1%, p