Does daily urine output really matter in renal transplantation?

Abstract

Our objective was to clarify the clinical outcome of renal transplantation based on residual daily urine output (RDUO). We retrospectively analyzed a prospective database of 276 patients who underwent renal transplantation (Tx) between January 2008 and December 2012. Patients had pre-transplantation daily urine output measurement of 24-h proteinuria and were clinically re-evaluated the day before transplantation. We included patients with no daily urine output and those with residual daily urine output. Real bladder capacity was not measured. We excluded patients with a history of lower urinary tract malformation, those treated by trans-ileal conduit or enterocystoplasty, and those with early graft thrombosis or graft primary non-function. Sex ratio, age at Tx, pre-Tx MHC antibodies levels, donor age, and cold ischemia duration were not significantly different between the 2 groups. Dialysis duration was longer in group I (p<0.001). The dialysis duration was correlated with the volume of residual urine output (r=0.12, p<0.0001). We found 14 (19.4%) urological complications in Group I (11 urinary leaks and 3 urethral stenosis) and 13 (6.4%) in Group II (5 urinary leaks and 8 stenosis). This difference was significant (p=0.0013 and relative risk [RR]=2.2). Absence of residual daily urine output was a risk factor of post-transplantation urinary leak (p<0.0001: RR=2.95). At 3 years, graft survival was 74.7% and 94.6%, respectively, in Group I and II (p=0.003). The absence of residual daily urine output seems to be a major risk factor for urological complications. Taking into account recipient residual daily urine output should modify surgical strategy during renal transplantation.