#3737 RENAL RESERVE IN LIVING KIDNEY DONORS: THE HIDDEN ROLE OF OVERWEIGHT

Abstract

Abstract Background and Aims Renal reserve (RR) is the capacity to increase glomerular filtration rate (GFR) under certain stimuli such as obesity, hyperglycaemia, metabolic syndrome, etc. The importance of the presence or absence of RR is unknown. We investigated the prevalence and factors associated with RR in a group of living donors for renal transplantation. Method We investigated RR before donation in 52 living kidney donors. GFR was measured by iohexol clearance before and after the stimulation of RR by endovenous amino acid infusion. The presence of RR was defined as an increase greater than 10% of basal GFR. According with the presence or absence of RR, subjects were grouped in those without RR; with RR and using RR. The latter was defined as the lack of increase in GFR after stimulation in patients with GFR > 100 mL/min. GFR was unadjusted to body surface area (BSA). The characteristics of these three groups were evaluated. Results 13 (25%) had no RR, 24 (46%) had RR and 15 (29%) were using RR. Subjects without RR was predominantly female (92%) with lower BSA and BMI than those with RR or using RR (BMI: 22 ± 3 vs 28 ± 3 and 29 ± 4, p < 0.005); also had a lower GFR than the other groups (84 ± 10 vs 95 ± 14 and 131 ± 22, p < 0.005). Subjects with RR or using RR had more frequently metabolic syndrome traits i.e. prediabetes than those without RR. Finally, subject using RR present larger kidney length than the other groups (right kidney: 11.3 ± 0.8 vs 10.3 ± 0.36 and 10.4 ± 0.8, p < 0.005; left kidney: 11.8 ± 0.5 vs 10.4 ± 0.6 and 10.7 ± 0.7, p < 0.005). No differences were observed regarding dyslipidaemia and arterial hypertension. Conclusion overweight and prediabetes may be factors that stimulate RR in a healthy population such as living kidney donors. Future implications of these factors, particularly after donation both in donors and recipients, deserve attention.