Background: The aim of our study was to determine which factors are associated with switching from oral hypoglycaemic agents to insulin therapy in patients with type 2 diabetes mellitus in general practice.
Methods: Longitudinal, observational study in a Dutch general healthcare centre. All pharmacologically treated patients with type 2 diabetes mellitus were included (n = 152). Comorbidity, laboratory results and medication use were obtained from the general practitioners' files.
Results: A total of 31 (20.4%) patients switched from oral hypoglycaemic agents to insulin therapy; they were significantly younger at the onset of diabetes, 50.5 versus 57.7 years. Fasting blood glucose levels and HbA(1c) values were significantly higher after the switch compared with patients on oral treatment, 10.0 mmol/l versus 8.4 mmol/l and 8.8% versus 7.9%, respectively. Concerning comorbidity, they suffered more frequently from acute myocardial infarction, lipid disorders, depression, retinopathy and atrial fibrillation. Cardiovascular disease in general was more often present in patients who switched over to insulin, 77.4% versus 52.9% (OR 3.1; CI 1.2-7.6).
Conclusions: Patients who switch over to insulin therapy are younger at diagnosis, suffer from more health problems besides diabetes, especially cardiovascular disease, and have worse metabolic control, compared with users of oral hypoglycaemic agents.