Para-perirenal distribution of body fat is associated with reduced glomerular filtration rate regardless of other indices of adiposity in hypertensive patients

Obesity is a well-known risk factor for the development and progression of chronic kidney disease. Recently, para-perirenal ultrasonographic fat thickness (PUFT) has shown to correlate with both total and visceral fat better than body mass index (BMI), waist circumference (WC), and other indices of obesity. Moreover, a local paracrine and mechanical action of the PUFT on kidney has been described in recent studies. Aim of our study was to assess the relationship between glomerular filtration rate (GFR) and PUFT in comparison with other anthropometric and ultrasonographic indices of adiposity. Two hundred and ninety-six hypertensive patients were enrolled. PUFT, cutis-rectis thickness and rectis-aorta thickness were obtained by ultrasonography. Anthropometric measures of adiposity were also measured. Estimated GFR was calculated using the CKD-EPI equation. Higher PUFT values were observed in patients with impaired renal function (P < 0.001), whereas no differences in BMI and WC were shown between groups divided by GFR. PUFT significantly correlated with GFR in all patients (r = −0.284; P < 0.001), with no differences in groups divided by sex, diabetes, or BMI. This association held in multivariate analyses also after correction for confounding factors, including other adiposity indices (P < 0.001). When receiver operating characteristic curves were built to detect a eGFR < 60 mL/minutes per 1.73 m2, a PUFT value ≤3.725 cm showed a negative predictive value of 94.0%, with the largest area under the curve (AUC: 0.700) among the variables considered. In conclusion, the relationship between PUFT and GFR seems to be more accurate and less influenced by the bias affecting traditional indices of adiposity.