Relationship between the thickness of erector spinae muscles and mortality in patients with pulmonary tuberculosis

Skeletal muscle mass is a known predictor of mortality in older patients. However, its relationship with tuberculosis is unclear. Skeletal muscle mass is determined by the cross-sectional area of erector spinae muscle (ESMCSA). Additionally, the erector spinae muscle thickness (ESMT) is an easier measurement than ESMCSA. This study investigated the relationship of ESMT and ESMCSA with mortality in tuberculosis patients.

We retrospectively collected the data of 267 older patients (age ≥65 years) who were hospitalized due to tuberculosis at the Fukujuji Hospital from January 2019 to July 2021. This included 40 patients with 60-day mortality (the death group) and 227 patients with 60-day survival (the alive group). Here, we assessed the correlations between ESMCSA and ESMT, and the data were compared between the two groups.

ESMT had a strong proportional relationship with ESMCSA (r = 0.991, p < 0.001). ESMCSA (median 670.2 mm2 [interquartile range (IQR): 585.1-760.9] vs. 914.3 mm2 [717.6-1141.6], p < 0.001) and ESMT (median 16.7 mm [15.4-18.6] vs. 21.1 mm [18.0-25.5], p < 0.001) were significantly lower in the patients in the death group than those of patients in the alive group. A multivariable Cox proportional hazard model for 60-day mortality showed significantly independent differences in ESMT (hazard ratio [HR] 0.870 [95% confidence interval (Cl): 0.795-0.952], p = 0.003) and ESMCSA (HR 0.998 [95% Cl: 0.996-0.999], p = 0.009).

This study demonstrated a strong correlation between ESMCSA and ESMT, which were risk factors for mortality in patients with tuberculosis. Therefore, using ESMT is easier to predict mortality than ESMCSA.