Background: We sought to characterize the risk of clinically significant chronic kidney disease (CKD) following radical nephrectomy (RN) or partial nephrectomy (PN). We examined kidney function outcomes using data from the VHA. The VHA is the largest integrated national health care system in the U.S. and uses a standardized electronic health record, including measures of vital signs, laboratory values, and cancer-specific data.
Methods: We identified patients treated with RN or PN in the VHA from 2001 to 2013. We extracted all available measures of preoperative kidney function (N = 120,746), postoperative kidney function (N = 584,043), and tumor-specific data. For patients with preoperative epidermal growth factor receptor (eGFR) > 30, we fit proportional hazards models to test the association with RN and the outcome of stage 4 CKD (eGFR < 30 or dialysis). We performed a parallel analysis of patients with normal or near-normal preoperative kidney function (eGFR ≥ 60) and the incidence of stage 3b CKD (eGFR < 45). We fit adjusted competing risks models to determine the risk of CKD or death.
Results: We identified a cohort of 14,129 patients with preoperative eGFR > 30 who underwent kidney cancer surgery with either RN (n = 9,759) or PN (n = 4,370). Patients treated with PN had a > 50% reduced risk (hazard ratio [HR] 0.49, 95% confidence interval [CI] 0.42-0.58) of stage 4 CKD (eGFR < 30) in our multivariable model after controlling for age, sex, race, comorbidities, year of surgery, and preoperative kidney function. This association remained (HR 0.39, 95% CI 0.32-0.48) after controlling for T stage in patients with tumor-specific data (N = 8,598). Patients with normal or near-normal preoperative kidney function (N = 8,089) treated with PN had a > 80% reduced risk (HR 0.17, 95% CI 0.14-0.21) of developing stage 3b CKD (eGFR < 45) compared with that of RN. All associations remained significant in our competing risk multivariable model.
Conclusions: Partial nephrectomy is associated with marked reduction in the incidence of clinically significant CKD com-pared with that of RN.