Diabetes diagnosis from administrative claims and estimation of the true prevalence of diabetes among 4.2 million individuals of the Veneto region (North East Italy).

•Algorithm for the identification of diabetes using administrative claims.•Successful validation vs. clinical diagnosis.•Combination with laboratory data to detect undiagnosed diabetes.•True prevalence of known plus undiagnosed diabetes estimated to be 7.50%.•Extensive study on the entire Veneto region (NE Italy).