Risk Factors for Chronic Kidney Disease in Adult Patients with Congenital Heart Disease and Its Relationship with Cardiovascular Mortality

<b>Background</b>: Patients with congenital heart disease (CHD) show risk factors for chronic kidney disease (CKD) and it is well known that CKD has a large negative impact on survival. <b>Methods</b>: Observational and prospective cohort study. Adult CHD patients and controls were matched for age and sex. <b>Results</b>: A total of 657 CHD adult patients (cases) and 1954 controls were studied. Median age in CHD patients was 30 (17-62) years and 373 (57%) were male. The prevalence of CKD (Glomerular filtration rate (GFR) < 60 mL/min/1.73 m²) was 0.2% and 4.5% in the control and CHD groups, respectively. Binary logistic regression analysis determined as risk factors for CKD in CHD patients: age [1.54 (1.04-1.28), <i>p</i> = 0.009], dyslipidemia [19.8 (1.35-301.1), <i>p</i> = 0.031], low iron concentration [0.96 (0.96-0.93), <i>p</i> = 0.048], cyanosis [25.7 (1.60-411.8), <i>p</i> = 0.022], and Down syndrome [46.8 (8.09-2710), <i>p</i> = 0.003]. During a follow-up time of 6.8 (1.2-10.5) years, cardiovascular mortality occurred in 31 patients with CHD showing, through the Kaplan-Meier test, a worse outcome among patients with CKD (<i>p</i> < 0.05) as was also seen in the univariate Cox regression survival analysis. However, after adjusting for other variables, this significance was lost, with age remaining as the unique independent prognostic factor. <b>Conclusions</b>: The prevalence of CKD was much higher in patients with CHD than in the control group; age, cyanosis, and Down syndrome were the predictors of a higher risk of CKD among CHD patients. Although CKD was associated with worse survival in CHD patients, only age was identified as an independent prognostic factor for cardiovascular mortality.