Whole and cortical kidney volume predict 5-year post-nephrectomy eGFR in Indian living kidney donors

Abstract

Aim: To study the additional utility of pre-nephrectomy whole and cortical kidney volumes (WKV, CKV) in predicting long-term post-nephrectomy kidney function in Indian living kidney donors (LKDs).

Methods: This retrospective cohort study included all LKDs who underwent nephrectomy between 1 January 2006 and 31 December 2015 at our centre, had pre-nephrectomy height, weight and computed tomography (CT) angiography with arterial and nephrographic phase documented, and 5-year post-nephrectomy creatinine values measured. Correlation between body surface area (BSA) adjusted pre-nephrectomy total CKV, WKV and pre-nephrectomy CKD EPI eGFR; BSA-adjusted remnant pre-nephrectomy CKV (rCKV), WKV (rWKV) and 5-year post-nephrectomy CKD EPI creatinine eGFR (5yeGFR_Cr ); predictors of 5yeGFR_Cr < 70% of pre-nephrectomy CKD EPI creatinine eGFR (pre-eGFR_Cr ), and an equation to predict 5yeGFR_Cr from pre-nephrectomy variables were calculated.

Results: A total of 196 LKDs (74% female, mean age 41.7 ± 11.0 years) were included in the study. Total WKV showed higher correlation with pre-nephrectomy eGFR than CKV, the highest with CKD EPI cystatin eGFR. Remnant WKV showed higher correlation than rCKV with post-nephrectomy eGFR_Cr and this increased over time. Older age, lower rWKV or rCKV, higher BSA, and higher pre-eGFR_Cr identified LKDs with 5yeGFR_Cr < 70% of pre-eGFR_Cr , with rCKV identifying a higher proportion (4.5%) of such LKDs. A model including rWKV or rCKV predicted 5yeGFR_Cr better than one including age, gender, BSA and pre-eGFR_Cr alone.

Conclusion: Inclusion of pre-nephrectomy remnant CKV and WKV into models for 5yeGFR_Cr and sub-optimal post-nephrectomy adaptation in Indian LKDs improves their accuracy. CKD EPI cystatin eGFR correlates better with functional renal mass.

Keywords: India; cortical kidney volume; estimated glomerular filtration rate; living kidney donor; whole kidney volume.