Background: There is limited evidence for the effectiveness of bariatric surgery in adolescents, and the associated complications. The main objective of the 4XL study was to clarify whether laparoscopic Roux-en-Y gastric bypass (LGBP) combined with lifestyle intervention is a safe and effective treatment method.
Material and method: Data were retrieved from an ongoing non-randomised intervention study of adolescents with morbid obesity that is comparing the effects of gastric bypass combined with lifestyle intervention versus lifestyle intervention alone.
Results: Altogether 39 patients (64 % girls) treated with a gastric bypass, and 96 patients (57 % girls) treated with lifestyle intervention were examined prior to the start of treatment and one year later. The average age at inclusion (SD) was 16.7 (1.0) years vs. 15.6 (1.3) years, and average BMI was 45.6 (4.4) vs. 43.3 (4.1) kg/m2 in the two groups. Average (95 % CI) percentage weight loss was 30 % (27 %-33 %) after surgery versus weight gain of 1 % (-1 % to 3 %) in the control group. The difference between the groups was 31 % (95 % CI 27 %-34 %, p<0.001). Cardiometabolic risk factors improved only after surgery. After gastric bypass, two early (<6 weeks) minor complications were recorded. One year after surgery, 4 (10 %), 8 (21 %) and 4 (10 %) of patients had anaemia, iron deficiency or low vitamin B12 levels respectively, and 20 of 33 patients (61 %) had low two-hour blood glucose (<2.8 mmol/l) after oral glucose tolerance testing.
Interpretation: The results support previous studies showing that gastric bypass is associated with significant weight loss in adolescent patients with morbid obesity. The 4XL study is currently too small and the follow-up time too short to allow the risk of long-term complications to be assessed.