The relationship between psoas muscle index, clinical outcomes and long-term mortality in hospitalised older patients: A retrospective and observational cohort study

Objectives

This study examined the association between the psoas muscle index (PMI), hospital clinical outcomes and long-term survival in older patients hospitalised in a geriatric ward.

Methods

This retrospective study included 173 patients aged 65 years or older hospitalised in a geriatric ward (August 2020–December 2023). The PMI was measured via abdominal CT and calculated as the psoas muscle area divided by body surface area (mm²/m²). The post-discharge status of discharged patients was assessed through telephone interviews.

Results

The median age of the patients (58%, female) was 80 years (65–112 years). The median PMI value was significantly lower in patients who died in the hospital than in those who survived (p = .01). In long-term follow-up, median PMI was significantly lower in female patients who died than in survivors (p = .02). In multiple regression analyses, PMI was shown to be independently associated with in-hospital mortality in all study populations and long-term mortality in female patients. In the whole study population, the optimal cut-off value of PMI for predicting in-hospital mortality was ≤407.3 mm²/m² (p = .02); for females, it was ≤406.5 mm²/m² (p < .001); for males, it was ≤633.9 mm²/m² (p = .03). In female patients, the optimal cut-off value of PMI for predicting long-term mortality was ≤406.5 mm²/m² (p = .02); however, for the whole population and male patients, it was not statistically significant.

Conclusions

This study demonstrates that low PMI might be related to increases in in-hospital and long-term mortality rates in hospitalised older individuals. The PMI measurement may be a potential marker for predicting mortality in hospitalised older patients.