High incidence of type 1 diabetes, type 2 diabetes and gestational diabetes in Central Iran: A six years results from Semnan health cohort.

Introduction: Diabetes incidence has increasingly risen in Iran and other low- and middle-income nations in recent decades. In the Semnan Greater Area of Iran, we evaluate the incidence of type 1 diabetes (T1D), type 2 diabetes (T2D), and gestational diabetes during 2015-2020 as well as their six-year trend. Methods: This is a retrospective analysis of data (n = 820401) from the Integrated Health System (sib) in Semnan province during 2015-2020. All diabetes cases with diagnostic codes based on the International Classification of Diseases 10 (ICD-10) are listed by year. The Grid Search method was used to obtain the exact number and time of points when the incidence of diseases changes significantly (Joinpoints). Average Annual Percent Change-Annual Percentage Change (AAPC-APC) values and slop changes in the estimated regression line with 95% confidence interval were utilized based on diabetes types to determine Joinpoints. P-value < 0.05 is considered statistically significant. Results: The proportions of diabetes types (T1D, T2D, and gestational diabetes) among 820401 diabetics were 4.18%, 94.84%, and 0.97%, respectively. APC value denotes that T1D has increased by 12.47% per year on average in this period (P-value < 0.01). The incidence of T2D and gestational diabetes has increased between 2015 and 2020 (APC = 15.02 and APC = 136.138, respectively; P-value < 0.1). Conclusions: In summary, the incidence of diabetes in Semnan province is constantly increasing. T2D, meanwhile, has a higher proportion. Nevertheless, gestational diabetes had the highest increase annually. Well-designed surveys investigating the reasons for diabetes increment especially gestational ones and its burden are needed.