Perirenal Adipose Tissue may be an Important Predictor of Adverse Kidney Outcomes in Living Kidney Donors

Obesity is a growing concern among living kidney donors (LKDs), with perirenal adipose tissue (PRAT) increasingly recognized as a key contributor to chronic kidney disease (CKD) risk. This study evaluates PRAT thickness in relation to kidney function, hypertension, and histological markers of fibrosis in LKDs.

We retrospectively analyzed 3226 LKDs from Mayo Clinic Minnesota and Arizona (2000-2019) with implantation kidney biopsies and predonation computed tomography (CT) angiograms. PRAT thickness was measured posteriorly and laterally from the retained kidney at the renal vein level and perirenal fat stranding (PFS) was graded. Histological assessments included nonsclerosed glomeruli, globally sclerosed glomeruli (GSG), interstitial fibrosis and tubular atrophy (IFTA), and luminal stenosis.

PRAT thickness and PFS increased with older age, especially in men. Black donors had the lowest PRAT and PFS measures. Compared with normotensive donors, donors with hypertension had significantly higher body mass index (BMI) (29.5 kg/m² vs. 27.2 kg/m²), posterior PRAT thickness (8.5 mm vs. 5.2 mm), lateral PRAT thickness (13.2 mm vs. 9.8 mm), and prevalence of PFS (36.8% vs. 19.4%); P < 0.0001 for all. Larger glomerular volume correlated with higher BMI and PRAT thickness; higher percentage of IFTA and IFTA foci density correlated with PFS > 0. In adjusted analyses, only posterior PRAT thickness was significantly associated with long-term estimated glomerular filtration rate (eGFR) < 45 ml/min per 1.73 m² (P = 0.0001), whereas BMI (P = 0.61) and lateral PRAT thickness (P = 0.99) did not. There was no association of PRAT and PFS with post-donation albuminuria.

PRAT thickness was a stronger predictor of postdonation renal outcomes than BMI. Incorporating PRAT assessment into donor evaluation may improve risk stratification and identify therapeutic targets for reducing CKD risk in LKDs.