Comparison of the thickness of the erector spinae muscles between aspiration pneumonia and bacterial pneumonia patients

Background and Aims: Aspiration pneumonia is generally associated with deterioration of skeletal muscle mass, which is usually evaluated by the erector spinae muscle cross-sectional area (ESM_CSA); however, no report has assessed ESM_CSAin patients with aspiration pneumonia. Furthermore, erector spinae muscle thickness (ESM_T) was developed to be easier to measure than ESM_CSA. Therefore, this study investigated the relationship between ESM_Tand ESM_CSAin aspiration pneumonia patients compared to bacterial pneumonia patients. Methods: We retrospectively collected data for 164 patients with aspiration pneumonia and 480 patients with bacterial pneumonia who were hospitalized at Fukujuji Hospital between September 2018 and May 2022. We assessed the correlations between ESM_CSAand ESM_Tand compared the data between the two groups. Results: ESM_Thad a strong, proportional relationship with ESM_CSAin all patients (r = 0.908, p< 0.001) and those with aspiration pneumonia (r = 0.896, p< 0.001). ESM_CSA(median 671.8 mm²[range 164.0–1636.7] vs. median 1057.0 mm²[range 161.3–2412.5], p< 0.001) and ESM_T(median 17.1 mm [range 6.95–34.4] vs. median 23.8 mm [range 6.95–43.7], p< 0.001) were significantly lower in patients with aspiration pneumonia. A multivariate analysis of aspiration pneumonia diagnosis showed significant independent differences from bacterial pneumonia in ESM_CSA(odds ratio 0.998 [95% CI: 0.996–0.999], p= 0.001) and ESM_T(odds ratio 0.90 [95% CI: 0.84–0.96], p= 0.002). Conclusion: This study demonstrates a strong correlation between ESM_CSAand ESM_T. ESM_Tcan be more easily used to evaluate skeletal muscle mass and can help in diagnosing aspiration pneumonia.