Impact of erector spinae muscle mass and quality on decline in swallowing function during hospitalization in older patients with pneumonia: single-center retrospective observational study in Japan

Background: Trunk muscle mass and quality may be related to swallowing function; however, it is unclear whether the same trend is observed in older patients with pneumonia. We aimed to determine the impact of the mass and quality of the erector spinae muscles (ESM), measured by chest computed tomography (CT), on the decline in swallowing function during hospitalization in older patients with pneumonia. Methods: The participants were patients hospitalized at Sanuki Municipal Hospital with a diagnosis of pneumonia who underwent pulmonary rehabilitation. The cross-sectional area of the ESM (ESM _CSA /BSA) was measured using chest CT images as an indicator of muscle mass, and the CT value of the ESM (ESM _CT ) was measured as an indicator of muscle quality. After calculating the cutoff values of ESM _CSA /BSA and ESM _CT that predict a score of ≥2 on the Functional Oral Intake Scale (FOIS), we classified the participants (n=452) into four groups: High ESM _CSA /BSA・ESM _CT , Low ESM _CSA /BSA, Low ESM _CT , and Low ESM _CSA /BSA・ESM _CT . Results: Multiple logistic regression analysis, adjusted for confounders, showed that Low ESM _CSA /BSA was significantly associated with FOIS change during hospitalization. Conclusions: Our results suggest that muscle mass is strongly associated with a decline in swallowing function during hospitalization in older patients with pneumonia.