Effects of bariatric surgery on renal function and associated factors with bivariate analysis: a cohort study

Background: Obesity is a global pandemic, caused by genetic, biological and social factors, increasing the risk of many chronic diseases, including kidney disease. Bariatric surgery can control associated comorbidities and also improve renal function. Thus, the aim of this study was to evaluate the effect of bariatric surgery on renal function and associated factors, through bivariate analysis. Methods: : A cohort, prospective, analytical study was carried out in the Department of surgery and obesity, in Campina Grande - Paraíba, Brazil. Thirty-five obese patients were evaluated in the preoperative period of bariatric surgery and after one year of bariatric surgery. Sociodemographic and anthropometric data were collected, body mass index was calculated, and renal function was estimated through the glomerular filtration rate. Results: : Predominantly female (71.4%) and white (77.1%) patients were observed. Regarding the type of bariatric surgery, most patients (65.7%) underwent the sleeve technique. There was no significant difference between the mean levels of cystatin C pre and post bariatric surgery. There was a significant improvement in the mean glomerular filtration rates in the postoperative period (p=0.09). In further analysis of the association between the variables: type of bariatric surgery, diabetes or hypertension outcomes, no association was observed with the outcome improvement in glomerular filtration rate, without statistical significance, respectively (p = 0.312; p =0.217; p = 0.476). Similarly, there was no statistically significant difference between the variable loss of body mass index, under the effect of bariatric surgery, in relation to the outcome of the glomerular filtration rate (p = 0.904). Conclusion: After analyzing the association between outcome of glomerular filtration rate and the studied variables, no association was observed between these variables, under the effect of bariatric surgery, with improvement in glomerular filtration rate. Thus, bariatric surgery is associated with improvement of renal function independently.