Nutritional Deficiencies Before and After Metabolic and Bariatric Surgery in Patients Above 50.0 kg/m2: A Single Center Study.

Purpose: Metabolic and bariatric surgery (MBS) is an effective treatment for patients with body mass index (BMI) above 50.0 kg/m² but nutritional deficiencies (ND) may arise. This study aimed to assess if patients with BMI above 50.0 kg/m² have more ND and require more supplementation after MBS compared to patients in lower BMI groups.

Materials and methods: Retrospective single center study including all patients submitted to MBS from 2019-2020. Several parameters were collected. Statistical analysis was performed to compare ND between BMI groups (<40.0 kg/m²; 40.0 to 49.9 kg/m²; ≥50.0 kg/m²), and between surgeries (Roux-en-Y gastric bypass [RYGB] vs. sleeve gastrectomy [SG]) in the group with BMI ≥50.0 kg/m².

Results: We identified 951 patients, 85 (9.0%) with BMI ≥50.0 kg/m², with RYGB performed in 644 (68.4%) patients. Pre-operatively, vitamin D deficiency was observed in 80.0% of patients with BMI ≥50.0 kg/m², with significant differences between BMI groups. At follow-up there were no significant differences in ND according to BMI groups. In patients with BMI ≥50.0 kg/m², vitamin B12 deficiency was more frequent after RYGB. At 2-year follow-up, 95.4% patients were taking multivitamin supplementation, and 52.4% required additional supplements, namely vitamin D.

Conclusion: ND are common in patients with BMI ≥50.0 kg/m², even before MBS. After surgery, patients with BMI ≥50.0 kg/m² may not have increased risk for ND, compared to other BMI groups. In these patients, RYGB resulted in an increased risk for vitamin B12 deficiency. Adequate supplementation and clinical follow-up are essential to mitigate these complications.