Prevalence and incidence of cardiovascular and renal diseases in type 1 compared with type 2 diabetes: A nationwide French observational study of hospitalized patients

Type 1 diabetes mellitus (T1DM) and type 2 diabetes mellitus (T2DM) increase risks of cardiovascular (CV) and renal disease compared with diabetes-free populations. There are only a few studies comparing T1DM and T2DM for the relative risk of these clinical events. All adult patients hospitalized in French hospitals in 2013 with at least 5 years of follow-up were identified and categorized by their diabetes status. A total of 50,623 patients with T1DM (age 61.4 ± 18.6, 53% male) and 425,207 patients with T2DM (age 68.6 ± 14.3, 55% male) were followed over a median period of 5.3 years (interquartile range: 2.8 - 5.8 years). Prevalence and event rates of myocardial infarction (MI), heart failure (HF), ischemic stroke, chronic kidney disease (CKD), all-cause death and CV death were assessed with age stratification of 10-year intervals. For clinical events during follow-up, we report hazard ratios (HRs) in T1DM relative to T2DM. The age and sex-adjusted prevalence of CV diseases was higher in T2DM for ages above 40 years whereas the prevalence of CKD was more common in T1DM between ages 18 and 70 years. During 2,033,239 person-years of follow-up, age and sex-adjusted HR event rates comparing T1DM, versus T2DM as reference, showed that MI and HF relative risks were increased above 60 years (1.2 and 1.4 -fold). HR of ischemic stroke did not markedly differ between T1DM and T2DM. Risk of incident CKD was 2.4-fold higher in T1DM above 60 years. All-cause death HR risk was 1.1-fold higher in T1DM after 60 years and the CV death risk was 1.15-fold higher in T1DM between 60 and 69 years compared to T2DM. Although the crude prevalent burden of CV diseases may be lower in T1DM than in T2DM, patients with T1DM may have a higher risk of incident MI, HF, all-cause death and CV death above 60 years of age, highlighting the need for improved prevention in this population.