The relationship between renal volume and histology in obese and nonobese kidney donors

Obesity and related kidney diseases have become a global epidemic problem. However, the underlying pathogenesis of obesity-related renal diseases has not been clearly understood. In this study, we explored the link between renal volume (RV) determined by computed tomography (CT) and renal histology together with functional parameters in an obese population.

Eighty-two kidney donors who underwent CT for the measurement of kidney volume and zero-hour renal biopsy for renal histology were included in this cross-sectional study. Protein creatinine clearance and eGFR were evaluated in 24-h urine specimens as indicators of renal function.

Mean body mass index (BMI) was 28 ± 4.2 kg/m(2); 32.9% (n = 27) were obese. Mean RV was 196 ± 36 cm(3). RV was positively correlated with BMI, body surface area and creatinine clearance and negatively with HDL-cholesterol in the whole population. Renal function parameters of obese subjects were better, and their renal volumes were higher compared with the nonobese subjects. In obese subjects, corrected RV was positively correlated with glomerular filtration rate (r = 0.46, P = 0.01) and negatively with sclerotic glomeruli (r = -0.38, P = 0.04) and chronicity index (r = -0.43, P = 0.02). In adjusted ordinal logistic regression analysis, corrected RV was significantly associated with chronicity index (OR: 0.96; P = 0.01).

In obese cases, decreased RV determined by CT is associated with worse renal histology. In this population, kidney imaging techniques may provide important clues about renal survival.