Long-Term Outcomes of Bariatric and Metabolic Surgery in Japan: Results of a Multi-Institutional Survey

Background: The number of bariatric procedures performed in Japan is increasing. There are isolated reports of bariatric surgery, but there have been no nationwide surveys including long-term data. Methods: We retrospectively reviewed data for patients who underwent bariatric and metabolic surgery throughout Japan and reviewed outcomes. Surveys were sent to ten institutions for number of procedures, preoperative patient weight and preoperative obesity-related comorbidities, and data at 1, 3, and 5 years postoperatively. Improvement of type 2 diabetes mellitus at 3 years after surgery was stratified by baseline ABCD score, based on age, body mass index, C-peptide level, and duration of diabetes. Results: Replies were received from nine of the ten institutions. From August 2005 to June 2015, 831 patients, including 366 males and 465 females, underwent bariatric procedures. The mean age was 41 years, and mean BMI was 42 kg/m². The most common procedure was laparoscopic sleeve gastrectomy (n = 501, 60 %) followed by laparoscopic sleeve gastrectomy with duodenojejunal bypass (n = 149, 18 %). Laparoscopic Roux-en-Y gastric bypass was performed in 100 patients (12 %), and laparoscopic adjustable gastric banding was performed in 81 (10 %). At 3 years postoperatively, the remission rate of obesity-related comorbidities was 78 % for diabetes, 60 % for hypertension, and 65 % for dyslipidemia. Patients with complete remission of diabetes at 3 years postoperatively had a higher ABCD score than those without (6.4 ± 1.6 vs 4.2 ± 2.0, P < 0.05). Conclusions: Bariatric and metabolic surgery for Japanese morbidly obese patients is safe and effective. These results are comparable with the results of previous studies.