Association of Urine Dipstick Proteinuria and Postoperative Renal Function Following Robotic Partial Nephrectomy.

INTRODUCTION

In patients with normal estimated renal function before robot-assisted partial nephrectomy (RPN), there is still a risk for de Novo chronic kidney disease (CKD). We assessed the role of dipstick spot proteinuria in risk stratifying patients for CKD progression.

MATERIALS AND METHODS

From our prospectively maintained, institutional review board-approved database of patients undergoing RPN, we queried those with estimated glomerular filtration rate (eGFR) >60 and bilateral functional units. We assessed proteinuria through dipstick (trace or above) on voided urine in preoperative urologic appointment <3 weeks before RPN. Proteinuric patients were compared with the remainder of the cohort with parametric comparisons for continuous and chi-squared analysis for categoric variables. Multivariate logistic regression analyses were performed assessing the risk of de Novo CKD stage III development, estimated by the CKD-EPI equation.

RESULTS

We found 269 patients with eGFR >60 preoperatively, of whom 57 (21%) had proteinuria preoperatively. In univariate analysis, these patients were more likely to be diabetic (p = 0.023) and to be on an angiotensin converting enzyme inhibitor or angiotensin receptor blocker (p = 0.001) but had similar age (p = 0.13), body mass index (p = 0.09), and tumor size (p = 0.56) with similar rates of hypertension (p = 0.07). At a median 16 months, controlling for confounding variables, preoperative proteinuria on urinary dipstick was associated with a 2.3× (95% confidence interval 1.03-4.95) increased risk of de Novo CKD stage III progression.

CONCLUSIONS

Patients with proteinuria preoperatively, despite a normal eGFR, likely have intrinsic medicorenal disease. These patients should be counseled preoperatively that they have a higher risk of CKD progression following RPN.