The authors retrospectively reviewed the charts of 778 patients from their single institutional database of patients who underwent partial nephrectomy. Of these patients, 634 had healthy, normal kidneys and 144 either had CKD or were at risk for developing CKD. “At risk” was defined as those patients with hypertension, diabetes, and/or a smoking history. Upstaging of CKD was determined using the estimated glomerular filtration rate (eGFR) calculated using the MDRD equation and postoperative creatinine values between 3 to 12 months.
There found no significant difference in the incidence of CKD upstaging between those with diseased and healthy kidneys, 31.5% and 38.2%, respectively (p = 0.15). On multivariable analysis, the degree of excisional volume loss was significantly associated with increased odds of CKD upstaging in both the diseased (OR 1.42, 95% CI 1.16 – 1.76, p = 0.001) and healthy kidneys (OR 1.63, 95% CI 1.03 – 2.61, p = 0.04). In addition. the duration of warm ischemia was significantly associated with increased odds of CKD upstaging in those with diseased kidneys (OR 1.04, 95% CI 1.00 – 1.09, p = 0.04).
The authors concluded that excisional volume loss affects the rate of CKD upstaging, irrespective of baseline renal function. Warm ischemia time has a greater influence on patients with diseased kidneys.
This study addresses the important and highly relevant issue of postoperative renal function in patients undergoing partial nephrectomy. A weakness of this study is the use of the MDRD study equation to calculate eGFR. The MDRD equation is known to be less accurate at eGFRs greater than 60 and the interquartile ranges of eGFRs for those patients with diseased and healthy kidneys were 79.7 – 100.0 and 80.2 – 97.1, respectively.
Presented by: Julien Dagenais, MD
Written by: Michael Owyong, Department of Urology, University of California-Irvine at the 2018 AUA Annual Meeting - May 18 - 21, 2018 – San Francisco, CA USA