The SURF (Italian observational study for renal insufficiency evaluation in liver transplant recipients): A post-hoc between-sex analysis

Background: Female sex has been reported as an independent predictor of severe post-liver transplantation (LT) chronic kidney disease. We performed a by sex post-hoc analysis of the SURF study, that investigated the prevalence of renal impairment following LT, aimed at exploring possible differences between sexes in the prevalence and course of post-LT renal damage. Methods: All patients enrolled in the SURF study were considered evaluable for this sex-based analysis, whose primary objective was to evaluate by sex the proportion of patients with estimated Glomerular Filtration Rate (eGFR) < 60 ml/min/1.73m2 at inclusion and follow-up visit. Results: Seven hundred thirty-eight patients were included in our analysis, 76% males. The proportion of patients with eGFR < 60 mL/min/1.73 m2 was significantly higher in females at initial study visit (33.3 vs 22.8%; p = 0.005), but also before, at time of transplantation (22.9 vs 14.7%; p = 0.0159), as analyzed retrospectively. At follow-up, such proportion increased more in males than in females (33.9 vs 26.0%, p = 0.04). Mean eGFR values decreased over the study in both sexes, with no significant differences. Statistically significant M/F differences in patient distribution by O'Riordan eGFR levels were observed at time of transplant and study initial visit (p = 0.0005 and 0.0299 respectively), but not at follow-up. Conclusions: Though the limitation of being performed post-hoc, this analysis suggests potential sex differences in the prevalence of renal impairment before and after LT, encouraging further clinical research to explore such differences more in depth.