RESUMEN
INTRODUCTION: Bariatric surgery is a first-line treatment for patients with obesity and diabetes. It is uncertain whether leptin has an influence on glycemia in the postoperative period. METHODS: A cohort study of thirty-eight individuals with obesity and diabetes who underwent laparoscopic Roux-en-Y gastric bypass was undertaken. The levels of leptin, glucose, and glycosylated hemoglobin were verified in the preoperative period and in the first and third postoperative months. RESULTS: The majority of patients were women (81.6%), and the mean age was 47.3 years (SD 8.8). The mean BMI was reduced by 17.75% (from 47.3 to 38.9 kg/m2) and the mean glycemia by 26.76%. Preoperative leptin had a moderate positive correlation with glucose level at the third month (Pearson r = 0.46, P = 0.02), but not with HbA1c. Patients with leptin above 27.34 ng/mL had a higher glucose level at the end of observation (101.9 versus 88.9, t test, P = 0.042). CONCLUSION: The search for factors that influence diabetes control after bariatric surgery is of major importance in clinical practice. Our study reported a level of leptin that can predict the prognosis of glycemic control after the intervention. This finding still needs to be validated and confirmed in other populations.