Bariatric Surgery increases risk of acute Kidney injury: Study

Written by Dr. Shravani Dali Published On 2025-08-29T20:45:43+05:30 | Updated On 29 Aug 2025 8:46 PM IST

Bariatric Surgery increases risk of acute Kidney injury: Study

A large population-based cohort study published in BMC Nephrology found that bariatric surgery is a double-edged sword for kidney health. While the procedure increases short-term risks—namely acute kidney injury (AKI) and kidney stones—it significantly lowers long-term chances of chronic kidney disease (CKD) and kidney failure requiring replacement therapy (KFRT).

Researchers in Denmark analyzed outcomes for nearly 19,000 adults who underwent Roux-en-Y gastric bypass or sleeve gastrectomy between 2006 and 2018, comparing them to over 94,000 matched individuals with overweight or obesity who did not undergo surgery. Median follow-up was just over eight years.

Within one year of surgery, 2.7% of bariatric patients experienced AKI—significantly higher than matched controls. Over ten years, 3.5% developed nephrolithiasis compared to lower rates in non-surgical peers BioMed Central PubMed. Adjusted hazard ratios confirmed elevated risk: AKI (aHR ≈ 1.63) and kidney stones (aHR ≈ 1.73) BioMed Central PubMed.

The encouraging flip side: ten-year risks of CKD (stage G3–G5) and KFRT were significantly lower in the surgery group. CKD risk dropped to aHR ≈ 0.41, and KFRT to aHR ≈ 0.63, compared to non-surgery controls BioMed Central PubMed.

The findings suggest bariatric surgery offers kidney protection in the long run—most likely driven by improved management of obesity-related comorbidities like hypertension, diabetes, and hyperlipidemia. However, the early risks of AKI and kidney stones—possibly due to volume shifts or oxalate handling—are real and warrant careful perioperative attention.

For clinicians, these results underscore the importance of closely monitoring renal function after bariatric procedures and implementing preventive strategies—hydration, renal monitoring, possibly dietary oxalate restriction—to mitigate early risks while aiming for those long-term gains.

Reference:

Sørensen, C. G., Jensen, S. K., Thomsen, R. W., Jespersen, B., Gribsholt, S. B., & Christiansen, C. F. (2025). Kidney outcomes after bariatric surgery: a population-based cohort study. BMC Nephrology, 26, Article 458. https://doi.org/10.1186/s12882-025-04378-8

Keywords: bariatric surgery, acute kidney injury, nephrolithiasis, chronic kidney disease, kidney failure requiring replacement therapy, BMI, Roux-en-Y gastric bypass, sleeve gastrectomy, renal outcomes, population-based cohort

bariatric surgeryacute kidney injurynephrolithiasischronic kidney diseasekidney failure requiring replacement therapyBMIRoux-en-Y gastric bypasssleeve gastrectomyrenal outcomespopulation-based cohort

Source : BMC Nephrology

Dr. Shravani Dali

Dr. Shravani Dali has completed her BDS from Pravara institute of medical sciences, loni. Following which she extensively worked in the healthcare sector for 2+ years. She has been actively involved in writing blogs in field of health and wellness. Currently she is pursuing her Masters of public health-health administration from Tata institute of social sciences. She can be contacted at editorial@medicaldialogues.in.