Clinical significance of diabetes likely induced by statins: Evidence from a large population-based cohort

Introduction. A large number of studies has shown that use of statins is accompanied by an increased risk of developing type 2 diabetes [1-5], which is thus currently listed as an inconvenience of these drugs that may attenuate in some patients their protective effect. However, several aspects of the statin-induced diabetes have not been adequately clarified. For example, albeit several hypotheses have been advanced, the mechanisms through which statins favour the alteration of glucose metabolism that leads to the appearance of hyperglycemia and diabetes remain unclear [4,6]. Furthermore, although statin-induced diabetes is generally believed not to offset the protective lipid-lowering effect of statins on the cardiovascular (CV) system [7-9], limited information exists on whether statin-induced diabetes has the same adverse prognostic significance of native diabetes, i.e., whether it is associated with a similar increasing risk of diabetes-related macrovascular complications. This information is of fundamental importance to reliably quantify the impact of statin-induced diabetes on the role played by statins on primary and secondary CV prevention [10,11]. Aims. Since we have previously shown that at the population level an increasing adherence with statin treatment is accompanied by a clear-cut progressive increase in the risk of new onset type 2 diabetes [12], thus the purpose of the present study was to provide information on the extent to which type 2 diabetes more likely induced by statins affects the risk of macrovascular complications to a similar or different degree compared to diabetes of a more likely native nature. Methods. The data used for this study were retrieved from the healthcare utilization databases of Lombardy, a Region of Italy which accounts for about 16% (almost ten million) of its population, by means of a record-linkage procedure among databases. In Italy, the whole population is covered by the National Health Service and in Lombardy this h