Association between obesity and absolute renal risk factors in patients with IgA nephropathy

Objective To investigate the influence of obesity on renal lesion in IgA nephropathy (IgAN) patients by analyzing the association between obesity and absolute renal risk factors (ARR). Method Clinical-pathological data of IgAN patients diagnosed by renal biopsy in General Hospital of Ningxia Medical University were collected retrospectively. According to the body mass index (BMI), patients were divided into non-obese group (BMI＜28, N-OB group) and obese group (BMI≥28, OB group). Their clinical characteristics, pathological index and ARR scores were compared. The relationship of BMI and ARR was analyzed by ordinal logistic regression models. Results (1) A total of 674 IgAN patients with mean age of 35.5±11.3 years were enrolled, including 94 in OB group and 580 in N-OB group respectively. Compared with those in the N-OB group, the proportion of male, age, mean arterial pressure, blood uric acid, blood triglyceride, diabetes mellitus and hypertension increased in OB group (all P＜0.01). Patients in OB group had lower estimated glomerular filtration rate (eGFR) and higher ARR score than those in N-OB group (all P＜0.05). (2) More severe thickening renal small artery wall and hyaline degeneration were observed in the OB group than in the N-OB group (all P＜0.01). There was no statistical difference between the two groups in Lee classification, Oxford classification, mesangial cell proliferation, glomerular sclerosis, crescent formation, renal tubular atrophy, interstitial inflammatory cell in filtration and endothelial cell proliferation. (3) After adjusting for age, sex, blood uric acid, serum albumin, eGFR, low density lipoprotein, glomerular sclerosis, interstitial inflammatory cell infiltration, renal tubular atrophy and vascular wall thickening, BMI was still an independent risk factors for ARR in IgAN patients (OR=1.09, 95%CI 1.03-1.14). Conclusions BMI is an independent risk factors for ARR in IgAN patients. Early prevention and control of obesity and its associated risk factors may improve outcomes of IgAN patients.