Association of Visceral Obesity and Glomerulomegaly Among Kidney Donors.

Abstract

OBJECTIVE: Due to increasing demand and shortage of kidneys for donation, there has been a liberalization of criteria with obese donors now being increasingly accepted. However, obesity causes glomerulomegaly, which is an established risk factor for future chronic kidney disease. Identifying a non-invasive obesity pattern most closely associated with glomerulomegaly may help inform the living kidney donor selection. METHODS: Implantation renal biopsy sections were reviewed on 1075 kidney donors (between 1999 and 2012), and the mean non-sclerotic glomerular volumes determined using the Weibel and Gomez stereological model. The 20 kidney donors with the largest glomerular volume were age and gender matched to the 20 kidney donors with the smallest glomerular volume. Abdominal obesity patterns were characterized from pre-donation abdominal CT images. The subcutaneous and visceral fat areas were measured at the umbilicus. Peri-renal (deep to the fascia but superficial to the capsule and para-renal (superficial to the fascia) fat for both kidneys were measured on cross-sectional scans at ¼, mid, and ¾ of kidney length, and averaged. The sinus fat was measured at the renal hilum for both kidneys and averaged. The waist circumference was assessed at the umbilicus. RESULTS: Mean age was 44 years and 70% were female in both groups. The mean ± SD glomerular volume was 0.0010 ± 0.0003 mm3 in the low and 0.0060 ± 0.0011 mm3 in the high group (p <0.001). The table compares fat distribution between these two groups.Table: No Caption available.CONCLUSION: In this pilot study, the proportional increase in visceral obesity with glomerulomegaly was greater than the other indices of obesity. Since contrast computed tomographic imaging is routinely performed during predonation kidney evaluations, visceral fat quantification could potentially be used to better inform the kidney donor selection process.