The influences of bariatric surgery on hemoglobin A1c in a sample of obese patients in Saudi Arabia

Background: Although the frequency of surgical weight loss interventions has increased in Saudi Arabia, literature describing the clinical outcomes of bariatric surgery in Saudi Arabia is limited. This study aimed to assess whether weight loss intervention improves hemoglobin A1c (HbA1c) in obese patients and to identify its associated factors. Patients and methods: A retrospective study was carried out on 318 patients with obesity class 1 or higher (body mass index [BMI] ≥ 30 kg/m²) who underwent laparoscopic sleeve gastrectomy or Roux-en-Y gastric bypass at King Abdulaziz Medical City in Riyadh, Saudi Arabia, between January 1, 2001 and March 31, 2017. Preoperatively and 12 months postoperatively, characteristics of patients were collected. BMI reduction was calculated, based on which patients were divided into three groups (0–9, 10–14, and >14 kg/m²). Results: The postoperative HbA1c was 5.83±0.9, while the baseline level was 6.74±2.1 (P=0.001). Fifty-eight of the 318 patients had diabetes. We observed significantly higher HbA1c in diabetic than in non-diabetic patients preoperatively, whereas an insignificantly different HbA1c was observed postoperatively. Among those who had minimal reduction in BMI (0–9 kg/m²), we observed significantly higher HbA1c in diabetic than in non-diabetic patients, whereas among those who had large reduction in BMI (10–14 kg/m²) and (>14 kg/m²), we observed insignificant differences in HbA1c in diabetic than in non-diabetic patients. Conclusion: Being a diabetic patient was related to a significant reduction in HbA1c levels postoperatively. The study suggests that the reduction in HbA1c levels could be modified by BMI, wherein greater reduction in BMI leads to greater reduction in HbA1c levels.