Association between the psoas muscle index and hospitalization for pneumonia in patients undergoing hemodialysis

Background Although muscle mass loss and pneumonia are common and crucial issues in hemodialysis (HD) patients, few reports have focused on their association, which remains unclear. This study assessed the association between skeletal muscle mass and the incidence of pneumonia in HD patients using the psoas muscle index (PMI). Methods This retrospective study included 330 patients on HD who were treated at a single center between July 2011 and June 2012. The observation period was between July 2011 and June 2021. Demographic, clinical, and HD data were collected, and the associations between PMI and hospitalization due to bacterial pneumonia were evaluated using Cox proportional hazards models adjusted for patients' background data. Additionally, the correlation between patient characteristics and PMI was evaluated using multivariable linear regression. Results Among 330 patients (mean age, 67.3 +/- 13.3; 56.7% male; median dialysis vintage 58 months, (interquartile range [IQR] 23-124), 79 were hospitalized for pneumonia during the observation period (median observation period was 4.5 years [IQR 2.0-9.1]). The multivariable Cox proportional analysis, which was adjusted for age, sex, dialysis vintage, diabetes mellitus, and stroke history and considered death as a competing risk, indicated that decreased PMI/(standard deviation) was closely associated with the development of pneumonia (hazard ratio: 0.67, 95% confidence interval: 0.47-0.95, p = 0.03). Conclusions Skeletal muscle mass was associated with the development of pneumonia in patients on HD and could be a useful marker for the risk of pneumonia.