Internal Medicine Resident McGill McGill University Westmount, Quebec, Canada
Background: Advances in congenital heart disease (CHD) management have improved survival, with most patients reaching adulthood. With the rising prevalence of diabetes mellitus (DM), an increasing number of adult CHD (ACHD) patients are developing DM, yet data remain limited on the incidence and prognostic effect of DM in ACHD patients.
METHODS AND RESULTS:
Methods: We identified 83,688 ACHD patients from the Quebec CHD database (1983-2017). Incidence rates of DM with the adjustment for competing risk of death were calculated among all ACHD patients, compared to rates in the general population and stratified by CHD lesion severity. Cox proportional hazard models allowing time-varying effect were built to assess the effect of DM on mortality. Predictors of mortality were evaluated using Cox proportional hazard and machine learning models in diabetic patients.
Results: Compared to the general Canadian population, ACHD patients have higher incidence rates of diabetes, a finding that is consistent among all age groups. Incidence of DM in ACHD patients increases by age, ranging from 3.62/1000 person-years for age group of 18-25 to 23.95/1000 person-years for age group of 65 and over. Patients with severe CHD lesions had significantly higher DM incidence than non-severe CHD patients in all age groups younger than 65. DM was independently associated with mortality with a hazard ratios (HR) of 1.37 (95% CI: 1.32–1.42) throughout patients’ adulthood regardless of their CHD lesion severity. Heart failure (HR: 1.65, 95% CI: 1.54–1.76), age of diabetes onset (HR 0.96, 95% CI 0.96-0.97), lung cancer (HR: 1.56, 95% CI: 1.37–4.32) and chronic kidney disease (HR: 1.55, 95% CI: 1.38–1.73) were strong predictors of mortality among the diabetic ACHD population.
Conclusion: This large population-based cohort study demonstrated higher rates of diabetes in ACHD patients compared to the general population as well as an age-dependent relationship between CHD severity and diabetes incidence, suggesting that ACHD patients, especially those with severe lesions, may benefit from early screening of DM. The study showed that DM independently increases mortality risk in patients with severe and non-severe CHD lesions. The findings of this study highlight the importance of prevention and early treatment of DM and can help guide long-term survival predictions in ACHD patients.
