Estimating the prevalence and incidence of treated type 2 diabetes using prescription data as a proxy: A stepwise approach on Iranian data

Type 2 diabetes is a serious health challenge, and large-scale studies on its prevalence in Iran are lacking. In pharmacoepidemiology, case-finding can be done by reviewing the prescription databases for specific drug(s) prescribed for a disease. We aimed to determine the prevalence and incidence of type 2 diabetes in Fars province, Iran, using prescription data and a stepwise approach to ascertain the results. A dataset of 3,113 insured individuals aged ≥35 years were selected. Their Prescription Data Centre records were reviewed for all drugs frequently used in controlling type 2 diabetes available in the Iranian pharmacopeia. Then we used a stepwise method for case-finding. In step one, each individual with a positive drug history for type 2 diabetes was labeled as an individual with diabetes. The next two steps were implemented for ascertainment of step one estimations. Prevalence of type 2 diabetes based on prescription, internist opinion, and phone call verification in 2015 and 2016 was 9.3% and 10.3%, 8.5% and 9.8%, and 7.2% and 8.7%, respectively. An incidence of 1.9% was determined for 2016. We obtained a realistic estimation of prevalence and incidence of treated type 2 diabetes, using prescription data which are large-scale, low cost, and real-time. •Prevalence of type 2 diabetes was 7.2% and 8.74% in 2015 and 2016.•Prevalence of type 2 diabetes raised by 1.5% from 2015 to 2016.•An incidence of 1.9% was determined for 2016.•Both prevalence and incidence were higher in women.•Metformin 500 and Glibenclamide 5 had equal or more than fair power (>70%) to identify the number of patients with type 2 diabetes.•The stepwise method yields a realistic estimation on prevalence and incidence of treated type 2 diabetes, using prescription data which is large-scale, cheap and real-time. Prevalence; Diabetes mellitus; Prescription drug.