Changes in weight following peroral endoscopic myotomy: results from a North American center

Background and study aims  Weight loss is a feature of untreated achalasia. While weight gain after achalasia treatment is expected, little data exist about the extent of it, particularly after peroral endoscopic myotomy (POEM). We aimed to describe the changes in weight after POEM. Patients and methods  A retrospective analysis was performed of patients from March 2016 to March 2020 undergoing POEM by an experienced operator at an academic referral center in Kingston, Ontario, Canada. Data examined included pre- and post-POEM body mass index (BMI), procedural characteristics, and Eckardt scores. Results  Ninety-two patients underwent POEM during the study period, for 77 of whom follow-up data were available including BMI. Prior to POEM, the median BMI was 26. Six patients (7.8 %) were considered to be underweight, 24 (31.2 %) were normal, 26 (33.8 %) were pre-obese, and 21 (27.2 %) were obese. At a median follow-up of 15 months, the clinical success rate was 95 %. Patients in the normal weight and pre-obesity categories had a significant increase in weight post-POEM. Of the underweight patients, two (33.3 %) moved up to a normal weight category and two (33.3 %) became pre-obese. In the normal BMI category, eight (37.5 %) became pre-obese and one patient (4.2 %) became obese. Ten of the 26 pre-obese patients (38.4 %) were obese post-POEM. Seven of the obese patients (33.3 %) reached Class III (morbid) obesity at follow-up.  Conclusions  Patients may experience a marked increase in BMI following POEM, with over one-third of patients becoming pre-obese, obese or morbidly obese at follow-up in our study in a North American population. Further study is required to analyze weight gain patterns post-POEM.