An easy, fast, effective tool to monitor the incidence of type 1 diabetes among children aged 0-4 years in Italy: the Italian Hospital Discharge Registry (IHDR).

National data of type 1 diabetes incidence are currently missing in Italy. To fill this gap, we estimated the national rate of first hospitalizations for type 1 diabetes among children aged 0-4 years and resident in Italy, as well as rates for each of the twenty-one Italian regions. We extracted the first episode of hospitalization in years 2005-2010 from the Italian Hospital Discharge Registry (IHDR). Record-linkage procedure and cleansing data method were applied to exclude prevalent cases and potentially miscoded patients. At the end, 2,250 incident hospitalizations for type 1 diabetes were extracted. In the years 2005-2010, the mean nation-wide first hospitalization rate for type 1 diabetes in children aged 0-4 years was 13.4 (95% CI 12.8-14.0), 14.1 (95% CI 13.3-14.9) in males and 12.7 (95% CI 11.9-13.4) in females. A geographically heterogeneous pattern of incidence was found: even excluding Sardinia, incidence for this age range and calendar period tended to be slightly higher in Southern than in Northern Italy. Our incidence of first hospitalizations corresponds to the estimates of disease incidence obtained with different data sources by other authors in selected Italian regions. We provide, for the first time ever, the estimate of type 1 diabetes incidence for the overall population aged 0-4 years resident in Italy. When methodological cautions are adopted, IHDR emerges as a reasonable proxy of type 1 diabetes incidence and as a cost-effective tool for public health purposes.