Blood Urea Nitrogen to Creatinine Ratio at Listing is Associated with Poor Outcomes in Heart Transplant Recipients with Stage 3 Chronic Kidney Disease

PURPOSE Non-dialysis dependent patients with renal impairment undergoing heart transplantation (HT) alone are at significantly higher risk of mortality and poor renal outcomes compared with those undergoing heart-kidney transplantation (HKT). It remains unclear what parameters might identify patients who may benefit from HKT compared to HT alone. We investigated whether blood urea nitrogen to creatinine ratio (BCR) at time of HT listing among those with stage 3 chronic kidney disease (CKD) (estimated glomerular filtration rate (eGFR) between 30 and 59 ml/min/1.73 m2) is associated with higher risk of post-HT death or dialysis. METHODS We identified 159 patients who underwent HT alone at our institution between 1/2009 and 2/2018. Univariate and multivariate Cox-proportional regression analyses were used to investigate the association between BCR and composite risk of post-HT death or dialysis at 1 year. RESULTS At listing, average age was 55±10 years (74% male and 28% African American) and eGFR was 47 ± 8. Mean eGFR did not differ between those with the composite outcome (46 ± 8) and those without (47 ± 8; p = 0.60). Overall, 14 patients (9%) died and 25 (16%) needed dialysis by 1 year post-HT. The univariate and multivariate adjusted hazard ratios for continuous variable BCR as a predictor of the composite outcome were 1.05 [95% confidence interval (CI): 1.02, 1.09; p < 0.01) and 1.04 [95% CI: 1.01, 1.09; p = 0.02), respectively. Additional regression analyses and Kaplan-Meier survival curves are shown in the figure. CONCLUSION Heart transplant candidates with stage 3 CKD and elevated BCR at time of listing are at increased risk of post-HT mortality or dialysis. Further investigation of HKT outcomes among those with stage 3 CKD and elevated BCR at listing is warranted.