Symmetrical dimethylarginine outperforms CKD-EPI and MDRD-derived eGFR for the assessment of renal function in patients with adult congenital heart disease.

Abstract

Adults with congenital heart disease exhibit a 3-fold higher mortality in the presence of chronic kidney disease, hence assessment of renal function is crucial in this patient population. Formulas for the estimation of glomerular filtration rate (GFR) have not been evaluated in this patient population. Therefore, this study compares different markers and equations for the estimation of renal function in adults with congenital heart disease.
Renal function was assessed in 102 patients using the Modification of Diet in Renal Disease (MDRD) equation, the simplified MDRD equation, the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation and the Cockcroft-Gault formula. Additionally, symmetrical dimethylarginine (SDMA) was measured. Those parameters were compared to cystatin C-derived GFR using the Larsson equation.
GFR estimates using the original MDRD (r = 0.465, p < 0.001) and the CKD-EPI equation (r = 0.462, p < 0.001) showed a similar strong correlation with the cystatin C-based eGFR equation, while eGFR using the simplified MDRD equation showed a slightly weaker correlation (r = 0.439, p < 0.001). The Cockcroft-Gault formula showed no correlation at all to the cystatin C-based eGFR (r = 0.144, p = 0.17). The strongest correlation was observed for SDMA and cystatin C-based eGFR (r = -0.552, p < 0.001).
GFR in adults with congenital heart disease should be estimated using the original MDRD or the CKD-EPI formula. SDMA seems to be a promising marker of renal function for this patient group.