Impact of Sleeve Gastrectomy on Renal Function in Patients With Morbid Obesity: A One-Year Prospective Cohort Study

Background: Obesity is an independent risk factor for renal injury. A more favorable metabolic environment following weight loss may theoretically lead to improved renal function. We aimed to evaluate the evolution of renal function one year after sleeve gastrectomy in a large prospective cohort of patients with morbid obesity and assess the influence of fat-free mass (FFM) changes. Patients and Methods. We prospectively included 563 severely obese patients admitted for sleeve gastrectomy. Patients were systematically evaluated one year after surgery. The estimated glomerular filtration rate (eGFR) was calculated using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation. The FFM was estimated by analyzing computerized tomography (CT) scan sections from CT systematically performed two days and one year after sleeve gastrectomy to detect surgery complications. Results: . The mean age was 41.2±0.52 years. The mean body mass index was 43.5±0.3 kg/m 2 and 20.4, 30.5, and 30.7% of the included patients had type 2 diabetes, hypertension, and dyslipidemia, respectively. One hundred and fifteen patients were lost to follow-up at one-year post-surgery. The eGFR was significantly lower one year after sleeve gastrectomy than before surgery (87.8±0.9 versus 86.1±0.9, p<0.01). There was no difference in terms of post-surgery FFM loss between patients with an improved eGFR and those without (6.7±0.3 kg versus 6.76±0.5 kg, p=0.9). Furthermore, post-surgery changes in the eGFR did not correlate with the amount of FFM loss (r=0.1, p=0.18). Conclusion: Renal function assessed by eGFR is significantly improved at one-year post-sleeve gastrectomy, independent of changes in skeletal muscle mass.