Severity of ineffective esophageal motility is associated with utilization of skeletal muscle relaxant medications

Background: Ineffective esophageal motility (IEM) is the most common finding on high-resolution esophageal manometry (HREM). The underlying mechanisms for IEM remain to be fully elucidated. The aim of this study was to determine if utilization of skeletal muscle relaxants is associated with IEM, and with more severe subtypes of the disorder. Methods: Patients with diagnosis of IEM were gender and age matched to patients with normal HREM. Demographic information, symptoms, endoscopic findings, medication usage and medical comorbidities were recorded. Patients with a diagnosis of IEM were divided into subgroups based on mean distal contractile integral (DCI) and percentage of ineffective swallows, and assessed for clinically significant differences among patients with varying severity of underlying IEM. Key Results: A total of 118 patients were included in each group. There were no significant clinical differences between the group of patients with IEM and the group of patients with normal manometry. Within the group of IEM patients, those with mean DCI < 250 mm Hg/s/cm were more likely to be prescribed skeletal muscle relaxants (27.8% vs 11.0%, P =.044), and those using skeletal muscle relaxants had a larger mean percentage of ineffective swallows (81.1% vs 71.5%, P =.029). There were no significant differences across mean DCI subgroups in usage of any other medication, or in any of the demographic variables or disease comorbidities examined in this study. Conclusions & Inferences: Use of skeletal muscle relaxants is associated with more severe IEM, which may suggest a causal association between this class of medications and weaker esophageal peristalsis.