To Örebro University

BACKGROUND: Metabolic and bariatric surgery (MBS) can be challenging in patients with a very high body mass index (BMI). OBJECTIVES: The objective of the study is to evaluate the outcomes of different weight categories in a publicly funded healthcare system with high adherence to current guidelines for perioperative optimization.

SETTING: Nationwide, registry-based. METHODS: Based on nationwide data from the Scandinavian Obesity Surgery Registry, patients operated on with Roux-en-Y gastric bypass (RYGB), sleeve gastrectomy (SG), and biliopancreatic diversion with duodenal switch (BPD/DS) from 2007 until 2024 were included. Patients were stratified according to preoperative BMIs of 35-49 kg/m2, 50-59 kg/m2, 60-69 kg/m2, and ≥70 kg/m2.

RESULTS: The study included data for 83,057 patients. A postoperative complication occurred for 5855 (7.2%) with no difference between BMI groups. Operation time was longer for higher BMI groups for all procedures. At 2 years, patients lost the highest percentage of their total weight (%TWL) in all BMI categories after BPD/DS (37.9% ± 10.1% to 45.4% ± 15.3%), followed by RYGB (32.4% ± 8.6% to 36.8% ± 10.9%) and SG (26.6% ± 9.5% to 31.3% ± 8.9%). Mortality rates over a median of 9.8 years remained higher in the higher BMI groups (BMI: 50-59, odds ratio [OR] = 1.29 [1.15-1.46]; BMI: 60-69, OR = 1.66 [1.18-2.33]; BMI ≥70, OR = 2.33 [.96-5.68]).

CONCLUSION: MBS can be performed safely in patients with obesity class 4 or higher. Higher BMI was associated with longer operating times and superior weight loss, especially after BPD/DS. Despite greater weight loss and similar remission of metabolic co-morbid diseases, patients with higher preoperative BMI still have an increased long-term risk of all-cause mortality.