# Factors associated with the development of bacterial pneumonia and the preventive potential of peroral endoscopic myotomy in patients with esophageal motility disorders: a case–control study

## TL;DR

This study finds that older age, lower BMI, and spastic esophageal disorders increase pneumonia risk in patients with esophageal motility issues, and suggests that a procedure called POEM may help prevent pneumonia.

## Contribution

The study identifies risk factors for bacterial pneumonia in patients with esophageal motility disorders and evaluates the preventive potential of POEM for the first time.

## Key findings

- Older age, lower BMI, and spastic esophageal disorders are significant risk factors for bacterial pneumonia in patients with esophageal motility disorders.
- POEM treatment is associated with a reduced risk of bacterial pneumonia development.
- POEM may prevent pneumonia by reducing esophageal spasm and improving nutritional status.

## Abstract

Patients with esophageal motility disorders (EMDs) sometimes develop bacterial pneumonia (BP). However, factors associated with BP in patients with EMDs and whether peroral endoscopic myotomy (POEM) reduces BP development are unclear. Therefore, this study aimed to identify factors associated with BP development and evaluate the preventive potential of POEM in patients with EMDs.

This study included 623 patients diagnosed with EMDs at our institution between April 2015 and March 2023. Factors associated with BP were analyzed by comparing characteristics between patients who developed BP within 1 year before diagnosis using multivariable analysis. The potential of POEM to prevent BP development was assessed using Cox regression analysis, considering treatment status as a time-varying covariate.

Of the 623 patients, 31 (5.0%) developed BP within 1 year before diagnosis. Older age (odds ratio [OR] = 1.29, 95% confidence interval [CI] 1.04–1.59, p = 0.019; 10-year increments), lower body mass index (OR = 0.87, 95% CI 0.78–0.98, p = 0.026), and manometric diagnosis of spastic esophageal disorders (OR = 2.97, 95% CI 1.24–7.16, p = 0.015) were significantly associated with BP. Treatment status of POEM was proved to be a significant factor for developing BP using Cox regression analysis (hazard ratio = 0.17, 95% CI 0.039–0.75, p = 0.019).

Risk factors associated with BP in patients with EMDs were older age, lower body mass index, and manometric diagnosis of spastic esophageal disorders. POEM could decrease spasm-related bolus reflux, improve patients’ nutritional status through resolution of transit disturbance, and reduce respiratory complications, suggesting that POEM could help prevent BP development.

The online version contains supplementary material available at 10.1007/s00535-025-02238-8.