The Ontario Diabetes Database (ODD) is a population-based disease registry constructed using a validated algorithm based on hospitalizations and physician visits to identify individuals with physician-diagnosed diabetes mellitus in Ontario. The ODD is held at the Institute for Clinical Evaluative Sciences (ICES). An individual is said to have physician-diagnosed diabetes (excluding gestational diabetes) if at least one of the following criteria are met within a two-year period of time: (i) two primary care visits for diabetes OR (ii) one hospital admission for new or pre-existing diabetes. The ODD does not differentiate between type I and type II diabetes mellitus.