Introduction: At present, little data exists about the incidence of, and the risk factors associated with, metabolic syndrome (MetS) in patients with type 2 diabetes mellitus (T2DM). The aims of this present study were to assess the incidence and risk factors of MetS in people with T2DM using routinely collected data from a clinical information system at Isfahan Endocrine and Metabolism Research Centre, Iran.

Material and methods: During the mean (SD) follow-up period of 11.7 (4.8) years, 3,047 patients with T2DM who were free of MetS at baseline were examined to determine the incidence and predictors of progression to MetS. The mean (SD) age of participants was 50.4 (11.0) years, with a mean (SD) duration of diabetes of 6.3 (6.2) years at initial registration. A modified National Cholesterol Education Programme- Adult Treatment Panel III definition (with body mass index [BMI] instead of waist circumference) was used for the MetS.

Results: The prevalence of MetS was 63.2% (95% CI: 62.3, 64.1). The incidence of MetS was 28.5 (95% CI: 26.8, 30.2) (25.9 men and 30.9 women) per 1,000 patient-years based on 35,677 patient-years of follow-up. Multivariate analysis revealed that higher body mass index (BMI) and education, lower HbA1c and treatment with oral agent or insulin were associated with MetS.

Conclusions: These are the first estimates of the incidence and risk factors of MetS in patients with T2DM in Iran. These findings show that the natural course of MetS is dynamic. The clinical management of patients with T2DM will contribute significantly to MetS prevention.