Bariatric surgery and the diseased kidney: a 5-year assessment of safety and postoperative renal outcomes

Background: Obesity and its related medical conditions are well-established contributors to the development of chronic kidney disease (CKD). Metabolic and bariatric surgery (MBS), including procedures such as sleeve gastrectomy (SG) and Roux-en-Y gastric bypass (RYGB), is a potential intervention for these individuals. However, the heightened risk of postoperative complications casts doubts on the suitability of MBS in this population. Our aim is to evaluate the long-term safety, anthropometric and renal outcomes of MBS in patients with CKD. Methods: A retrospective review of patients who underwent primary laparoscopic MBS with a BMI ≥ 35 kg/m²and a preoperative diagnosis of stage 2 to 5 CKD. Criteria for CKD diagnosis and staging were based on estimated glomerular filtration rate measurements in accordance with established guidelines. Anthropometric and renal outcomes were measured at 3-, 6-, 12-, 24- and 60-months postoperatively. Results: A total of 302 patients (177 SG, 125 RYGB) were included. RYGB was preferred for patients with stage 3 CKD, while SG was more common in stages 4 and 5. At 5-year follow-up, percentage of total weight loss was higher in the RYGB cohort compared to SG (25.1% vs. 18.6%, p= 0.036). Despite SG patients having more advanced CKD, the incidence of late complications was significantly higher following RYGB, with 11 incidents (8.8%), compared to the SG cohort with only 4 cases (2.3%) (p= 0.014). In those with preoperative CKD stage 3, 76 patients (43.2%) improved to stage 2, with another 9 patients (5.1%) improving further to stage 1. Of all patients, 63 (20.8%) eventually received a successful renal transplant. Conclusions: MBS is an effective strategy for sustained weight loss in patients with CKD with acceptable complications rates. RYGB leads to a higher percentage of overall weight loss, albeit with an elevated likelihood of late surgical complications. Future studies are needed to determine the safety of MBS in this demographic.