Predictors of switching to insulin from non-insulin therapy in patients with type 2 diabetes mellitus

Aims: To estimate the switching rate and to identify factors that predict switch from non-insulin to insulin therapy in patients with type 2 diabetes using routinely collected data from a clinical information system at Isfahan Endocrine and Metabolism Research Centre, Iran. Methods: During the mean (SD) follow-up period of 9.3 (3.4) years, 6896 non-insulin-treated patients with type 2 diabetes at baseline have been examined to determine predictors of switches to insulin therapy. Their treatment at the last clinic visit was compared with the initial visit treatment. The mean (SD) age of participants was 51.2 (10.3) years with a mean (SD) duration of diabetes of 5.8 (5.9) years at initial registration. Results: The switch to insulin from non-insulin therapy was 2.5 (95% confidence interval 2.4, 2.6) (2.2 men and 2.7 women) per 100 patient-years based on 64,540 patient-years of followup. Using a Cox's proportional hazards model, younger age at diagnosis, female gender, higher BMI and HbA(1c) were significant predictors of switch to insulin treatment. Conclusions: These are the first estimate of switch to insulin from non-insulin therapy in Iran. Younger age at diagnosis, female gender, higher BMI and HbA1c at registration were identified as predictors of switching to insulin. (C) 2010 Elsevier Ireland Ltd. All rights reserved.