title: Para- and perirenal fat thickness is an independent predictor of chronic kidney disease, increased renal resistance index and hyperuricaemia in type-2 diabetic patients.
abstract: BACKGROUND
  Many interfering factors may reduce the reliability of waist circumference (WC) measurement in estimating the risk for chronic kidney disease (CKD) associated with obesity. Therefore, we determined the independent associations of para- and perirenal ultrasonographic fat thickness with the main markers of kidney function.
  
  
  METHODS
  A cross-sectional study was performed in 151 type-2 diabetic subjects. Para- and perirenal fat thickness was measured from the inner side of the abdominal musculature to the surface of the kidneys. CKD was defined as eGFR < 60 mL min(-1)1.73 m(-2).
  
  
  RESULTS
  Using both univariate and multivariate regression analyses, eGFR, renal resistance index and uricaemia were best predicted by para- and perirenal fat thickness even when BMI and waist circumference were further added in the statistical model (r(2): 0.366, P = 0.001; r(2): 0.529, P = 0.005; r(2): 0.310, P = 0.026, respectively), whereas waist circumference and BMI did not contribute independently of para- and perirenal fat thickness. Albuminuria was predicted by waist circumference but not by para- and perirenal fat thickness. In subjects with waist circumference above the diagnostic values of metabolic syndrome (48M/59F), eGFR significantly and progressively declined across tertiles of para- and perirenal fat thickness (87.0 ± 27.9 vs 83.5 ± 26.0 vs 62.3 ± 30.6 mL min(-1) 1.73 m(-2), adjusted P < 0.0001) despite comparable waist circumference, and an increasing frequency of CKD was observed across tertiles of subjects with waist circumference both below and above the metabolic syndrome diagnostic values (P < 0.05).
  
  
  CONCLUSIONS
  Para- and perirenal fat thickness is an independent predictor of kidney dysfunction in type-2 diabetes explaining an important proportion of the variance of eGFR, renal resistance index and uricaemia.
authors.affiliation: Unit of Endocrinology and Metabolic Diseases, Department of Medical Sciences and 2Unit of Nephrology, University of Foggia, Italy.
authors.forename: Olga
authors.initials: O
authors.lastname: Lamacchia
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Nicastro
authors.forename: Donatella
authors.initials: D
authors.lastname: Camarchio
authors.forename: Umberto
authors.initials: U
authors.lastname: Valente
authors.forename: Rosaria
authors.initials: R
authors.lastname: Grisorio
authors.forename: Loreto
authors.initials: L
authors.lastname: Gesualdo
authors.forename: Mauro
authors.initials: M
authors.lastname: Cignarelli
mesh_terms: D000419:Albuminuria / Q000209:etiology; D015992:Body Mass Index; D003430:Cross-Sectional Studies; D048909:Diabetes Complications; D003924:Diabetes Mellitus, Type 2 / Q000503:physiopathology*; D005260:Female; D006801:Humans; D033461:Hyperuricemia / Q000209:etiology*; D050152:Intra-Abdominal Fat; D007676:Kidney Failure, Chronic / Q000175:diagnosis* / Q000209:etiology*; D008297:Male; D024821:Metabolic Syndrome / Q000209:etiology; D008875:Middle Aged; D012307:Risk Factors; D055105:Waist Circumference; D049629:Waist-Hip Ratio