Predictive factors of chronic kidney disease stage V after partial nephrectomy in a solitary kidney: A multi-institutional study

Objective: Partial Nephrectomy (PN) in a solitary kidney is at risk of chronic kidney disease (CKD) stage V and/or haemodialysis (HD). Our objective was to determine predictive factors of CKD stage V in this population. Material & Methods: Data from 300 patients were retrospectively collected from 16 tertiary centres. Clinical and operative parameters, tumor characteristics and renal function before surgery were analyzed. Patients with and without CKD stage V (defined as MDRD<15. ml/min) were compared using χ2 and Student-t tests for qualitative and quantitative variables, respectively. Predictive factors of CKD stage V were evaluated with a multivariable analysis using a Cox regression model. Results: Median age and BMI were 63 years old and 26. kg/m², respectively. Most of the patients (65%) were male with an anatomic solitary kidney (88.3%). Median tumor size was 4. cm and 98% were malignant tumors. Median operative time, blood loss and clamping time were 180. min, 350. ml and 20. min respectively. Renal cooling was used in 19.3% and clamping of the pedicle was performed in 61.6%. Twenty five patients (8.5%) presented post operative CKD stage V at last follow-up and 18 underwent HD (6%) post-operatively because of acute renal insufficiency. There was no difference between CKD stage V and non CKD stage V patients concerning Charlson index, operative time (180. min vs 179. min, p = 0.39), blood loss (475. ml vs 350. ml, p = 0.51), use of renal cooling and type of clamping. Patients with CKD stage V were older (70 vs 63 years old, p = 0.005), had a lower baseline renal function (clearance MDRD 41 vs. 62. ml/min, p<0.0001) and an increased tumor size (p = 0.02). Complications occurred in 91 patients (30%) with 16% of minor (Clavien 1-2) and 14% of major (Clavien > 2) complications, respectively. In multivariable analysis, baseline MDRD, BMI, and the occurrence of a minor complication were independent predictive factors of post operative CKD stage V. Conclusion: PN in a solitary kidney is at risk of post-operative CKD stage V and HD. Pre-operative altered renal function and post operative complications are the main predictive factors of permanent CKD stage V.