Nutritional deficiencies after bariatric surgery in patients with BMI ≥ 50 Kg/m2: what is the real problem?

Abstract

Introduction: Metabolic and Bariatric Surgery (MBS) is an effective treatment for patients with superobesity (SO), BMI ≥ 50 Kg/m2. These procedures, namely Roux-en-Y Gastric Bypass (RYGB) and Sleeve Gastrectomy (SG), may result in nutritional deficiencies. This study aims to assess prevalence and risk factors for nutritional deficiencies following MBS in patients with SO. Methods: Retrospective single center study including all patients submitted to MBS between January/2019 and December/2020. Several parameters were collected. Statistical analysis was performed to compare nutritional deficiencies between BMI groups (<40Kg/m2; 40 to 49.9Kg/m2; ≥50 Kg/m2), and between surgeries (RYGB vs SG) in the SO group. Results: We identified 951 patients, 85 (9,0%) with BMI ≥ 50 Kg/m2, with RYGB performed in 644 (68,4%) patients. Pre-operatively, vitamin D deficiency was observed in 80,0% of SO patients, with significant differences between BMI groups. At follow-up there were no significant differences in nutritional deficiencies according to BMI groups. In patients with SO, we observed that only vitamin B12 deficiency was more frequent after RYGB. At 2-year follow-up, 95,4% patients were taking multivitamin supplementation and 37,6% required additional specific supplements. Conclusion: Nutritional deficiencies are common in patients with BMI ≥ 50 Kg/m2, even before MBS. After surgery, patients with SO may not have increased risk for nutritional deficiencies, compared to other BMI groups. In patients with SO, RYGB resulted in an increased risk for vitamin B12 deficiency. Adequate supplementation and clinical follow-up are essential to mitigate these complications.