RESUMO
BACKGROUND: Glomerular filtration rate is a key physiologic variable with a central role in clinical decision making and a strong association with prognosis in diverse populations. Reduced estimated glomerular filtration rate (eGFR) is common among adults with congenital heart disease (ACHD). METHODS: We conducted a prospective cohort study of outpatient ACHD ≥18â¯years old seen in 2012-2017. Creatinine and cystatin C were measured; eGFR was calculated using either the creatinine or cystatin C Chronic Kidney Disease-Epidemiology Collaboration equation (CKD-EPICr and CKD-EPICysC, respectively). Survival analysis was performed to define the relationship between eGFR and both all-cause mortality and a composite outcome of death or nonelective cardiovascular hospitalization. RESULTS: Our cohort included 911 ACHD (39⯱â¯14â¯years old, 49% female). Mean CKD-EPICr and CKD-EPICysC were similar (101⯱â¯20 vs 100⯱â¯23â¯mL/min/1.73 m2), but CKD-EPICr estimates were higher for patients with a Fontan circulation (nâ¯=â¯131, +10⯱â¯19â¯mL/min/1.73 m2). After mean follow-up of 659â¯days, 128 patients (14.1%) experienced the composite outcome and 31 (3.4%) died. CKD-EPICysC more strongly predicted all-cause mortality (eGFR <60 vs >90â¯mL/min/1.73 m2: CKD-EPICysC unadjusted HRâ¯=â¯20.2 [95% CI 7.6-53.1], C-statisticâ¯=â¯0.797; CKD-EPICr unadjusted HRâ¯=â¯4.6 [1.7-12.7], C-statisticâ¯=â¯0.620). CKD-EPICysC independently predicted the composite outcome, whereas CKD-EPICr did not (CKD-EPICysC adjusted HRâ¯=â¯3.0 [1.7-5.3]; CKD-EPICr adjusted HRâ¯=â¯1.5 [0.8-3.1]). Patients reclassified to a lower eGFR category by CKD-EPICysC, compared with CKD-EPICr, were at increased risk for the composite outcome (HRâ¯=â¯2.9 [2.0-4.3], Pâ¯<â¯.0001); those reclassified to a higher eGFR class were at lower risk (HRâ¯=â¯0.5 [0.3-0.9], Pâ¯=â¯.03). CONCLUSIONS: Cystatin C-based eGFR more strongly predicts clinical events than creatinine-based eGFR in ACHD. Creatinine-based methods appear particularly questionable in the Fontan circulation.