Impact of bariatric surgery on patients with chronic kidney disease and severe obesity: multiple-linked population-based cohort study.

Abstract

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. 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. 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. 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.