31 Jan 2026 • Patients undergoing malabsorptive bariatric surgery showed a markedly more lithogenic urine profile than those receiving restrictive procedures, raising concern for higher postoperative kidney stone risk.

Researchers assessing 24-hour urine chemistry within a year of surgery found that malabsorptive procedures were linked to substantially higher rates of hyperoxaluria (51.4% vs 25.5%), hypocitraturia (71.4% vs 36.4%), and acidic urine (54.3% vs 20.0%). Malabsorptive surgery nearly tripled the odds of hyperoxaluria (OR 2.95) and was associated with fourfold higher odds of hypocitraturia (OR 4.13), along with increased hypomagnesuria and low urine pH—key drivers of nephrolithiasis risk.

Routine postoperative monitoring of 24-hour urine chemistry, early dietary counseling, and multidisciplinary follow-up may be critical to reduce nephrolithiasis in this population.

Source: Science Report | Read full story