A Simple Clinical Tool for Stratifying Risk of Clinically Significant CKD after Nephrectomy: Development and Multinational Validation

Abstract

BackgroundClinically significant CKD following surgery for kidney cancer is associated with increased morbidity and mortality, but identifying patients at increased CKD risk remains difficult. Simple methods to stratify risk of clinically significant CKD after nephrectomy are needed.MethodsTo develop a tool for stratifying patients’ risk of CKD arising after surgery for kidney cancer, we tested models in a population-based cohort of 699 patients with kidney cancer in Queensland, Australia (2012–2013). We validated these models in a population-based cohort of 423 patients from Victoria, Australia, and in patient cohorts from single centers in Queensland, Scotland, and England. Eligible patients had two functioning kidneys and a preoperative eGFR ≥60 ml/min per 1.73 m2. The main outcome was incident eGFR <45 ml/min per 1.73 m2 at 12 months postnephrectomy. We used prespecified predictors—age ≥65 years old, diabetes mellitus, preoperative eGFR, and nephrectomy type (partial/radical)—to fit logistic regression models and grouped patients according to degree of risk of clinically significant CKD (negligible, low, moderate, or high risk).ResultsAbsolute risks of stage 3b or higher CKD were <2%, 3% to 14%, 21% to 26%, and 46% to 69% across the four strata of negligible, low, moderate, and high risk, respectively. The negative predictive value of the negligible risk category was 98.9% for clinically significant CKD. The c statistic for this score ranged from 0.84 to 0.88 across derivation and validation cohorts.ConclusionsOur simple scoring system can reproducibly stratify postnephrectomy CKD risk on the basis of readily available parameters. This clinical tool’s quantitative assessment of CKD risk may be weighed against other considerations when planning management of kidney tumors and help inform shared decision making between clinicians and patients.

Kidney Microstructural Features at the Time of Donation Predict Long-term Risk of Chronic Kidney Disease in Living Kidney Donors

“…We assessed for a follow-up eGFR less than 45 mL/min/1.73 m 2 as an outcome in addition to eGFR less than 60 mL/min/1.73 m 2 ; this lower threshold is considered a more clinically significant definition of CKD after a nephrectomy. 21 To assess the validity of self-reported serum creatinine level, we correlated the self-reported serum creatinine level to the temporally closest available electronic serum creatinine level in the local donor subset with laboratory testing (within the Mayo Clinic Health System).…”

Kidney failure, CKD progression and mortality after nephrectomy

“…When evaluating all-cause mortality, participants were censored on the date the database was updated or date lost to follow-up. All analyses were stratified by baseline eGFR (< 45 and ≥ 45 mL/min per 1.73m 2 ), which was considered a clinically significant cut-point [13]. The reference group was defined as the cohort with diabetic nephropathy as primary cause of CKD and a baseline eGFR ≥ 45 mL/min per 1.73m 2 .…”

More than ancillary records: clinical implications of renal pathology examination in tumor nephrectomy specimens

“…Our study provides new data based on a European population with its particular genetic, environmental, socio-economic backgrounds and varying incidence of conditions associated with RCC, such as diabetes or hypertension. Many teams currently strive to improve the identification of patients at risk of reduced kidney function after renal surgery and establishing prediction models mostly based on clinical data [ 9 , 10 ]. The inclusion of pathology findings could, in our view, ameliorate the predictive power of such tools leading to the discovery of additional relevant kidney lesions in a noticeable number of patients.…”