Association of Albuminuria With Major Adverse Outcomes in Adults With Congenital Heart Disease

Abstract

Albuminuria is associated with adverse outcomes in diverse groups of patients, but the importance of albuminuria in the emerging population of increasingly complex adults with congenital heart disease (ACHD) remains unknown. To assess the prevalence, risk factors, and prognostic implications of albuminuria in ACHD. This prospective study assessed a cohort of ambulatory patients aged 18 years and older who were examined at an ACHD referral center and enrolled in the Boston ACHD Biobank between May 17, 2012, to August 5, 2016. Albuminuria was defined as an urine albumin-to-creatinine (ACR) ratio of 30 mg/g or more. Death or nonelective cardiovascular hospitalization, defined as overnight admission for heart failure, arrhythmia, thromboembolic events, cerebral hemorrhage, and/or disease-specific events. We measured the ACR of 612 adult patients with CHD (mean [SD] age, 38.6 [13.4] years; 308 [50.3%] women). Albuminuria was present in 106 people (17.3%) and was associated with older age (patients with ACR <30 mg/g: mean [SD]: 37.5 [13.2] years; vs patients with ACR ≥30 mg/g: 43.8 [13.1] years; P < .001), presence of diabetes mellitus (ACR <30 mg/g: 13 of 506 [2.6%]; vs ≥30 mg/g: 11 of 106 [10.4%]; P < .001), lower estimated glomerular filtration rate (ACR <30 mg/g: median [interquartile range (IQR)]: 103.3 [90.0-116.4] mL/min/1.73 m2; ACR ≥30 mg/g: 99.1 [78.8-108.7] mL/min/1.73 m2; P = .002), and cyanosis (ACR <30 mg/g: 23 of 506 [5.1%]; vs ACR ≥30 mg/g: 21 of 106 [22.6%]; P < .001). After a mean (SD) follow-up time of 270 (288) days, 17 patients (2.5%) died, while 68 (11.1%) either died or experienced overnight inpatient admission. Albuminuria predicted outcome, with 30 of 106 patients with albuminuria (28.3%) affected vs 38 of 506 patients without albuminuria (7.5%; hazard ratio [HR], 3.0; 95% CI, 1.9-4.9; P < .001). Albuminuria was also associated with increased mortality (11 of 106 [10.4%]; vs 6 of 506 [1.2%] in patients with and without albuminuria, respectively; HR, 6.4; 95% CI, 2.4-17.3; P < .001). Albuminuria was associated with the outcomes only in patients with a biventricular circulation (HR, 4.5; 95% CI, 2.5-8.0) and not those with single-ventricle circulation (HR, 1.0; 95% CI, 0.4-2.8; P = 0.01 compared with biventricular circulation group). Among 133 patients (21.7%) in NYHA functional class 2, albuminuria was strongly associated with death or nonelective hospitalization. Albuminuria is common and is associated with increased risk for adverse outcome in patients with ACHD with biventricular circulation. Albuminuria appears especially useful in stratifying risk in patients categorized as NYHA functional class 2.