Chronic kidney disease in patients with congenital heart disease - a nationwide cohort study

Abstract Introduction Previous studies have shown an association between patients with congenital heart disease (CHD) and chronic kidney disease (CKD). We recently observed an increased prevalence of CKD in children and young adult CHD population, and as nowadays the majority of patients survives into adulthood this might become an increasing complication. However, it is not clear there is an increased risk to develop CKD in CHD patients compared to those without CHD. Purpose To investigate the incidence, risk and risk factors for CKD in children and adults with CHD (0–47 years old), compared to age- and sex-matched controls without CHD. Method Patients born with CHD between 1970 and 2017 were identified using data from the Swedish health register. Each patient with CHD was matched by birth year and sex to ten controls without CHD from the general population. Follow-up data were collected until 2017. Results We identified 71,936 CHD patients (52% male) who were matched to 714,457 controls during mean follow-up of 17.6 years (±12.8). Overall, 379 (0.5%) patients with CHD and 679 (0.1%) controls developed CKD; the risk of CKD was 6,4 times (95% confidence interval (CI): 5.65–7.27, p<0.001) higher in patients with CHD compared to controls. The greatest risk of CKD was in patients with severe non-conotruncal defects (HR 11.31, 95% CI: 7.37–17.36, p<0.001). The incidence of CKD increased exponentially with age but was in patients with and without CHD; however, at age of 47 years the cumulative incidence of CKD was 2.2% and 0.5% in patients with and without CHD respectively. Both absolute and relative risk of CKD was greater in CHD patients in the recent birth cohort (born between 1997–2017) (HR 9.98, 95% CI: 8.05–13.37) (incidence 28.1 per 100,000 person-years) compared to older patients (1970–1996) (HR 5.02 95% CI: 4.28–5.89) (incidence 39.5 per 100,000 person-years). Diabetes mellitus was the only risk factor that associated with the risk of CKD in CHD patients. Conclusion In the present nationwide cohort study, we found that patients with CHD have an over 6-fold risk of developing CKD compared to matched controls without CHD. The incidence of CKD increases with age, but also younger CHD patients are at risk, prompting action to establish regular follow-up of renal function in all patients with CHD, and identify individuals at risk as early as possible. Further mapping of risk factors and effects of kidney disease on the CHD population is also required. Funding Acknowledgement Type of funding sources: Public hospital(s). Main funding source(s): The Swedish state and the Swedish Research Council