OBJECTIVES1) To estimate the excess risk of death and complications associated with diabetes in adults aged 35 years and older and newly diagnosed with diabetes compared to those without diabetes; and 2) to calculate cumulative relative risks for death and complications associated with diabetes in newly diagnosed cases of diabetes in adults aged 35 and over.METHODSNewly diagnosed type 1 and 2 diabetes cases aged 35 and over were identified from the Ontario Diabetes Database and matched 1:2 using propensity scores with controls (non-diabetes cases). Using linked administrative databases in the province, data on death and the following complications were recorded: myocardial infarction, stroke, angina, heart failure, blindness, amputation, nephropathy and cataract. Kaplan-Meier curves were calculated to estimate the probability of being event-free for those with and without diabetes for up to 10 years of follow-up.RESULTSA total of 610 852 patients aged 35 and over with diabetes were matched with 1 221 704 patients without diabetes. For those with diabetes vs. those without, there was a statistically significant increased relative risk at 10 years for death (1.42, 95% CI 1.42–1.42), myocardial infarction (2.09, 95% CI 2.09–2.10), stroke (1.88, 95% CI 1.88–1.88), angina (1.53, 95% CI 1.53–1.53), heart failure (2.52, 95% CI 2.53–2.52), amputation (6.82, 95% CI 6.82–6.82), nephropathy (2.90, 95% CI 2.90–2.90), blindness (1.21, 95% CI 1.21–1.22) and cataract (1.33, 95% CI 1.32–1.33).CONCLUSIONSThe information provided in this study can be used to target clinical practice at complications typically associated with diabetes and can be used as inputs for long-term disease and economic modelling.