Kidney outcomes after bariatric surgery: a population-based cohort study

Abstract Background Bariatric surgery may mitigate obesity-related chronic kidney disease (CKD) but may concurrently increase the risk of acute kidney injury (AKI) and hyperoxaluria. We examined kidney outcomes after bariatric surgery. Methods Using population-based registries, we included individua...

Full description

Saved in:
Bibliographic Details
Main Authors: Christian Goul Sørensen, Simon Kok Jensen, Reimar Wernich Thomsen, Bente Jespersen, Sigrid Bjerge Gribsholt, Christian Fynbo Christiansen
Format: Article
Language:English
Published: BMC 2025-08-01
Series:BMC Nephrology
Subjects:
Online Access:https://doi.org/10.1186/s12882-025-04378-8
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Abstract Background Bariatric surgery may mitigate obesity-related chronic kidney disease (CKD) but may concurrently increase the risk of acute kidney injury (AKI) and hyperoxaluria. We examined kidney outcomes after bariatric surgery. Methods Using population-based registries, we included individuals with Roux-en-Y gastric bypass (RYGB) or sleeve gastrectomy (SG) in Denmark between 2006 and 2018. These were age- and sex-matched 1:5 to individuals with hospital-diagnosed overweight/obesity without bariatric surgery. Cumulative incidences (risks) of AKI, nephrolithiasis, CKD (stage G3–G5), and kidney failure with replacement therapy (KFRT) were computed, accounting for the competing risk of death. Cox regression was used to estimate hazard ratios (HR) adjusted for age, sex, and comorbidity. Results We included 18,827 individuals with bariatric surgery (17,200 RYGB and 1,627 SG) and 94,135 individuals in the matched overweight/obesity cohort (median age 41 years, median follow-up 8.1 years). The one-year risk of AKI following bariatric surgery was 2.7%, while the ten-year risks of nephrolithiasis, CKD, and KFRT were 3.5%, 0.4%, and 0.2%, respectively. When comparing individuals with bariatric surgery with those with overweight/obesity, the adjusted HRs were increased at 1.63 (95% CI; 1.38, 1.92) for AKI and 1.73 (95% CI; 1.56, 1.91) for nephrolithiasis. In contrast, adjusted HRs were decreased at 0.41 (95% CI; 0.26, 0.66) for CKD and 0.63 (95% CI; 0.42, 0.95) for KFRT. Similar results were observed versus a population comparison cohort. Conclusions Bariatric surgery was associated with an increased risk of AKI and nephrolithiasis, while long-term risks of CKD and KFRT were lower than in matched individuals with overweight/obesity.
ISSN:1471-2369