Does Glomerular Filtration Rate at Discharge After Partial Nephrectomy Predict Long-Term Glomerular Filtration Rate Stability?

Abstract

Introduction: Being able to predict glomerular filtration rate (GFR) plateau after partial nephrectomy (Pnx) is an important goal in providing patients with a confident projection of maintained renal function. As such, in an ethnically and socioeconomically diverse, inner city cohort of patients undergoing Pnx, we compared preoperative (pre-op) and day of discharge (DC) GFR to that of long-term GFR measured at 12-18 months to evaluate postoperative (post-op) GFR stability. Methods: A total of 162 patients who had undergone minimally invasive Pnx at a single institution between 2010 and 2016 were reviewed. Patients with the following available measurements were included: pre-op GFR, DC GFR, and long-term GFR (12-18 months after DC). Multivariate linear regression was performed to assess factors predictive of long-term GFR, including estimated blood loss, warm ischemic time, tumor size, length of stay, pre-op GFR, DC GFR, race, chronic kidney disease, diabetes mellitus, and hypertension. Results: Mean pre-op GFR, DC GFR, and long-term GFR were 70.754, 68.326, and 66.526\u2009mL/(minute\u2009·1.73\u2009m2), respectively. Mean GFR change was -4.228 pre-op to long term and -1.800 DC to long term. No significant difference was observed between means of DC GFR and long-term GFR (p\u2009=\u20090.248) as well as between means of pre-op GFR and DC GFR (p\u2009=\u20090.062). A significant difference was observed between pre-op GFR and long-term DC GFR (p\u2009=\u20090.002). On multivariate analysis, both pre-op GFR (β\u2009=\u20090.532; 95% confidence interval [CI]\u2009=\u20090.256-0.808; p\u2009≤\u20090.001) and DC GFR (β\u2009=\u20090.312; 95% CI\u2009=\u20090.089-0.537; p\u2009=\u20090.007) were found to be strong predictors of long-term GFR (R2\u2009=\u20090.608). Conclusions: Long-term GFR in a highly ethnically diverse inner city population recovering from Pnx is stable relative to GFR measured at DC from the hospital. Our findings demonstrate that patients experience a GFR plateau after surgery, resulting in minimal change in renal function at a mean of 14 months post-op.