Bariatric Surgery can Reduce Albuminuria in Patients with Severe Obesity and Normal Kidney Function by Reducing Systemic Inflammation

Obesity causes renal problems including albuminuria. Bariatric surgery (BS) improves albuminuria. We investigated whether albuminuria is reduced by weight loss per se or by improved systemic inflammation induced by weight loss after BS. Patients older than 18 years who received BS in Soonchunhyang University Hospital from 01 January 2011 to 31 December 2011 were included. Other inclusion criteria included body mass index (BMI) >= 30 kg/m(2), creatinine level <= 1.0 mg/dL, and no overt proteinuria (trace amount or undetectable by dipstick). The patients were followed at 1 and 6 months after BS. Forty-three patients were analyzed. Three patients were men, 10 patients had diabetes, and 12 patients had hypertension. All patients had normal renal function (creatinine <= 1.0 mg/dL), and estimated glomerular filtration rate was 115.7 +/- 16.5 mL/min/1.73 m(2). There were significant reductions in body weight, BMI, high-sensitivity C-reactive protein (hs-CRP), and urine albumin-to-creatinine ratio (ACR). There were positive correlations between delta hs-CRP and delta body weight (r = 0.349, p = 0.043) or delta body mass index (BMI, r = 0.362, p = 0.035); between hs-CRP and body weight (r = 0.374, p = 0.001), BMI (r = 0.431, p < 0.001). Multivariate analysis using a linear mixed model demonstrated that hs-CRP (beta = 0.5364, p = 0.026) was an independent risk factor affecting ACR. Our study suggests that BS can reduce albuminuria in patients with severe obesity and normal kidney function by reducing systemic inflammation.