Background—Renal insufficiency in patients with ischemic heart disease and acquired heart failure is associated with higher mortality and morbidity. We studied the prevalence of renal dysfunction in adult patients with congenital heart disease (ACHD) and its relation to outcome.

Methods and Results—A total of 1102 adult patients with congenital heart disease (age 36.0±14.2 years) attending our institution between 1999 and 2006 had creatinine concentration measured. Glomerular filtration rate (GFR) was calculated with the Modification of Diet in Renal Disease equation. Patients were divided into groups of normal GFR (90 mL · min^-1 · 1.73 m^-2), mildly impaired GFR (60 to 89 mL · min^-1 · 1.73 m^-2), and moderately/severely impaired GFR (<60 mL · min^-1 · 1.73 m^-2). Survival was compared between GFR groups by Cox regression. Median follow-up was 4.1 years, during which 103 patients died. Renal dysfunction was mild in 41% of patients and moderate or severe in 9%. A decrease in GFR was more common among patients with Eisenmenger physiology, of whom 72% had reduced GFR (<90 mL · min^-1 · 1.73 m^-2, P<0.0001 compared with the remainder), and in 18%, this was moderate or severe (P=0.007). Renal dysfunction had a substantial impact on mortality (propensity score–weighted hazard ratio 3.25, 95% CI 1.54 to 6.86, P=0.002 for moderately or severely impaired versus normal GFR).

Conclusions—Deranged physiology in adult patients with congenital heart disease is not limited to the heart but also affects the kidney. Mortality is 3-fold higher than normal in the 1 in 11 patients who have moderate or severe GFR reduction.