BACKGROUND: Chronic kidney disease (CKD) is prevalent among patients with obesity, contributing to increased morbidity and mortality. Metabolic bariatric surgery (MBS) may improve kidney outcomes, but its long-term effects remain unclear. The aim of this study was to examine the association between bariatric surgery and mortality and major adverse kidney events (MAKE) in patients with a diagnosis of CKD and severe obesity.
METHODS: Patients with a diagnosis of CKD (stage ≥3 and estimated glomerular filtration rate (eGFR) ≤60 ml per min per 1.73 m2) and BMI ≥35 kg/m2 or who underwent bariatric surgery from 2010 to 2016 in Ontario, Canada, were included. Non-surgical controls were identified from a primary care database. Multiple-linked administrative databases were used to define confounders, including age, BMI, sex, co-morbidities, socio-economic status, psychiatric history, healthcare utilization, substance misuse, and cancer screening. The primary outcomes were all-cause mortality and MAKE (a composite outcome of mortality, 50% decline in eGFR, dialysis initiation, and hospital admission for heart failure, myocardial infarction, and acute kidney injury). A multivariable Cox proportional hazards model was used for analysis.
RESULTS: Among 1538 patients (563 surgical and 975 non-surgical) followed for a median of 7.7 years, there were 285 deaths (207 (21.2%) non-surgical and 78 (13.9%) surgical). MBS was associated with 52% lower hazards of mortality (HR 0.48 (95% c.i. 0.34 to 0.67)) and 53% lower hazards of MAKE (HR 0.47 (95% c.i. 0.39 to 0.57)). Benefits were greater in females, patients aged >55 years, and those with a BMI >40 kg/m2.
CONCLUSION: MBS was associated with reduced mortality and improved kidney outcomes in CKD patients, particularly in older individuals, females, and those with a higher BMI, highlighting its potential role in high-risk patients.