Bariatric Surgery Improves Kidney Function via Reduced Systemic Inflammation

New Orleans—Obese patients are at risk for renal disease, including proteinuria, chronic kidney disease (CKD), and progression to end-stage renal disease. Proteinuria can be reduced and renal function can be improved with bariatric surgery; other benefits associated with weight loss include improved blood pressure, improved glucose homeostasis, and reduced systemic inflammation.

It is unclear whether the mechanism by which bariatric surgery reduces albuminuria is the direct result of weight loss per se or the result of improved systematic inflammation associated with weight loss. Researchers in the Republic of Korea, led by Nam-Jun Cho, MD, conducted a prospective cohort study designed to determine whether weight loss directly reduces albuminuria or whether improvement of systematic inflammation induced by weight loss reduces albuminuria. The researchers reported study results during a poster session at Kidney Week 2017. The poster was titled Bariatric Surgery Reduces Proteinuria in Severely Obese Patients with Normal Kidney Function by Reducing Systematic Inflammation.

The study cohort included patients >18 years of age who underwent bariatric surgery at the Soonchunhyang University Hospital from January 1, 2011, to December 31, 2011. Inclusion criteria were body mass index (BMI) ≥30 kg/m2, serum creatinine level ≤1.0, and without over proteinuria (dip stick ≤ trace). Follow-up occurred at 1 and 6 months postsurgery.

Of the 43 patients in the study cohort, three were men, 10 had diabetes, and 12 had hypertension. Following bariatric surgery, 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 change in hs-CRP and change in body weight or change in BMI. In a multivariate analysis using linear mixed model, hs-CRP was an independent risk factor affecting ACR.

“Our results suggest that weight loss by bariatric surgery directly improves systemic inflammation, which subsequently leads to reduced albuminuria,” the researchers said.

Source: Cho NJ, Gil H-W, Choi C-Y. Bariatric surgery reduces proteinuria in severely obese patients with normal kidney function by reducing systemic inflammation. Abstract of a poster presented at the American Society of Nephrology 2017 Kidney Week, November 4, 2017, New Orleans, Louisiana.