Bariatric surgery and renal function: a precarious balance between benefit and harm

Medical treatment of obesity and lifestyle modification have limited effectiveness in treating it in morbidly obese individuals. Importantly, bariatric surgery is regarded as the only therapy that is effective in maintaining significant weight loss in morbidly obese individuals. Despite the fact that bariatric surgery-induced weight loss is associated with a significant decrease in morbidity and mortality and improvement in renal function, bariatric surgery has recently been shown to be associated with a significant risk of nephrolithiasis. The main risk factor for nephrolithiasis is increased excretion of urinary oxalate. In this review, we discuss the association between bariatric surgery, an increased risk of renal stone formation and oxalate nephropathy.