Does bariatric surgery improves kidney function? A cohort study

Background: Obesity is a global epidemic that may cause renal dysfunction. Weight loss in the postoperative follow-up of bariatric surgery may improve renal function in these patients. Thus, the purpose of this study was to give insight on the subject using a sensible biomarker (cystatin C). Methods This cohort was performed in the Obesity Department from Campina Grande – Paraiba, Brazil. It was randomly enrolled 35 obese who underwent bariatric surgery (12 bypass and 23 sleeve) with follow-up of at least one year. The ages ranged from 24 and 57 years. Those with thyroid disease and with renal disease, with microalbuminuria ≥ 30mg/dL, were excluded. Serum levels of creatinine and cystatin C were measured, and the glomerular filtration rate (GFR) was estimated using the CKD Epi (chronic kidney disease epidemiology collaboration) cystatin-creatinine equation. The investigation was approved by the Ethics Committee. Results Twenty five women (71.4%) and 10 men (28.5%) were randomly recruited for the research. The most frequent associated morbidities were: sexual dysfunction (n = 17–48.5%); blood hypertension (n = 15–42.8%); type II diabetes (n = 13–37.1%); anxiety (n = 14–40.0%); and depression (n = 12–34.2%). Twenty three (65.7%) patients underwent sleeve technique and 12 (34.2%) bypass surgery. It was observed a significant reduction of BMI in the post-operative follow-up – p < 0.0001. There was a significant improvement of glomerular filtration rates (p = 0.0091). The improvement of renal function was more significant among those who underwent sleeve surgery as compared to bypass (p = 0.0008). Conclusion It was observed improvement of the majority of morbidities after bariatric surgery, as well as renal function, in obese individuals. Despite these results, larger and longer term outcome cohorts are required for better answer of the main purpose of this health issue.