Bariatric Surgery for CKD

Q) I know that diabetes can be controlled with bariatric surgery. Is there any proof that it also helps with kidney disease?

With obesity reaching epidemic proportions in the United States, the number of patients undergoing bariatric surgery has increased in recent years. The procedure has been identified as the most effective intervention for the morbidly obese (BMI > 35).^{1, 2}

Obesity is an independent risk factor for the development and progression of chronic kidney disease (CKD).³ It causes changes in the kidney, including hyperfiltration, proteinuria, albuminuria, and reduced glomerular filtration rate (GFR); however, the underlying mechanisms are still poorly understood.⁴ Research has demonstrated bariatric surgery’s positive effect on morbidly obese patients with CKD, as well as its benefit for patients with diabetes and hypertension—the two major causes of CKD.^1,2

Several studies have found that weight loss resulting from bariatric surgery improves proteinuria, albuminuria, and GFR.^2,3,5-9 Findings related to serum creatinine (SCr) have been somewhat conflicting. In severely obese patients, the surgery was associated with a reduction in SCr. This association persisted in those with and without baseline CKD, hypertension, and/or diabetes.⁵ However, other studies found that the procedure lowered SCr in patients with mild renal impairment (SCr 1.3-1.6 mg/dL) but increased levels in those with moderate renal impairment (SCr > 1.6 mg/dL).¹⁰ Because the effects of bariatric surgery on kidney function appear to differ based on CKD stage, further research is needed.