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<1 5 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.