Albuminuria Prevalence in Fontan Patients: A Systematic Review and Meta-Analysis

Patients with a Fontan circulation are at risk for chronic kidney disease (CKD), which is defined as persistently reduced glomerular filtration rate (GFR) <60ml/min/1.73² or elevated marker of kidney injury such as urinary albumin-to-creatinine ratio (UACR) >30mg/g. We determined the prevalence of albuminuria in patients with a Fontan circulation. The MEDLINE, EMBASE, Trip, and Cochrane databases were searched for studies reporting the prevalence of albuminuria in Fontan patients. Case reports, reviews, and univentricular patients pre-Fontan completion or post-heart transplantation were excluded. Studies were assessed for potential confounders and measurement, patient selection, intervention, and reporting biases, reported in a table. After systematic review, the pooled prevalence of albuminuria was calculated using the quality effects model for meta-analysis. Secondary outcomes were the clinical determinants of albuminuria. Thirteen studies were included in the systematic review, of which 11 were included in the meta-analysis (6 prospective, sample size per study 25-195 patients, 873 patients in total). The pooled prevalence of albuminuria was 28.4% (95% confidence interval 23.5-33.5%). GFR was mostly preserved in these patients. Albuminuria was associated with elevated systemic venous pressure in 5 studies. Other associations were inconclusive. The main limitations of our study are the predominantly retrospective and cross-sectional nature of the included studies with small sample sizes and heterogeneous study populations. Our findings show albuminuria is more prevalent than reduced GFR in patients with a Fontan circulation, implicating the potential value of UACR in addition to GFR when screening for CKD in these patients.