Impact of sleeve gastrectomy on renal function in patients with morbid obesity: a 1-year prospective cohort study.

Abstract

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. We prospectively included obese patients admitted for sleeve gastrectomy between February 2014 and November 2016. We also included a historical observational cohort of patients undergoing sleeve gastrectomy between January 2013 and January 2014 who had FFM evaluation. Patients were systematically evaluated 1year 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 2days and 1year after sleeve gastrectomy to detect surgery complications. Five hundred sixty-three patients fulfilled the inclusion criteria. The mean age was 41.2 ± 0.5years. The mean body mass index was 43.5 ± 0.3kg/m2 and 20.4, 30.5, and 30.7% of the included patients had type 2 diabetes, hypertension, and dyslipidemia, respectively. One hundred fifteen patients were excluded and four hundred forty-eight patients were finally included in the analysis. The eGFR was significantly higher 1year 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 ± 0.3kg versus 6.8 ± 0.5kg, 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). Renal function assessed by eGFR is significantly improved at 1-year post-sleeve gastrectomy, independent of changes in skeletal muscle mass.