Persistent body-weight change on achalasia and peroral endoscopic myotomy: a multicenter cohort study

The distribution of body weight in patients with achalasia and after peroral endoscopic myotomy (POEM) has not been investigated. The role of body weight assessment after treatment remains unclear.

Using the multicenter achalasia cohort, the frequency of underweight (body mass index [BMI] < 18.5 kg/m²) and overweight (BMI ≥ 25.0 kg/m²) and their associated clinical characteristics were analyzed. After POEM, risk factors for insufficient- (underweight persistently) and excessive- (responded to overweight) weight gainers were investigated. The correlation between BMI-increase rate and severity of esophageal symptoms post-POEM was evaluated.

Among 3,410 patients, 23.0% and 15.7% were underweight and overweight, respectively. Factors associated with underweight were higher age, female sex, severe symptoms, high lower esophageal sphincter (LES) pressure, and non-dilated esophagus (all p < 0.01). Longitudinal analyses revealed that weight gain post-POEM was achieved after a long duration (≥ 12 months; p < 0.01). In 528 patients post-POEM, the frequency of underweight reduced to 8.3% (p < 0.01). Risk factors for insufficient-weight gain (36.1% of underweight patients) included low BMI (p < 0.01) and high LES pressure (p = 0.03) and conversely for excessive-weight gain. Machine learning models based on patient characteristics successfully predicted insufficient- and excessive-weight gainers with an area under the curve value of 0.74 and 0.75, respectively. Esophageal symptoms post-POEM did not correlate with BMI increase.

Underweight is not solely a condition of advanced achalasia. After POEM, insufficient- or excessive-weight gainers are not rare and can be predicted preoperatively. Body weight change is an independent nutrition parameter rather than a part of the assessment of residual esophageal symptoms.