Prognostic significance of novel muscle quality index utilization in hospitalized adults with cancer: A secondary analysis.

Background: This study aimed to investigate and propose novel approaches to calculate muscle quality index (MQI) using muscle mass derived from single-frequency bioelectrical impedance analysis (SF-BIA) and calf circumference in both unadjusted and body mass index (BMI)-adjusted forms. In addition, we examined their prognostic significance in patients with cancer.

Methods: A secondary analysis was conducted on a prospective cohort study of patients with cancer. Handgrip strength was measured. SF-BIA was conducted to estimate appendicular lean soft tissue (ALST, in kilograms). MQI was calculated using three approaches: (1) the ratio of handgrip strength to ALST (MQI_SF-BIA), (2) the ratio of handgrip strength to calf circumference (MQI_{calf circumference}), and (3) the ratio of handgrip strength to BMI-adjusted calf circumference (MQI_{adj. calf circumference}). Maximally selected log-rank was calculated to estimate their cutoff values to predict survival.

Results: Two hundred eighty-four patients were included (51.1% men; median age, 61 years). Solid tumors were the most frequent (89.8%). All approaches to MQI (MQI_SF-BIA, MQI_{calf circumference}, and MQI_{adj. calf circumference}) were independent predictors of 6-month mortality. The found cutoffs were (1) MQI_SF-BIA (<1.52 for men, <0.63 for women), (2) MQI_{calf circumference} (<0.74 for men, <0.24 for women), and (3) MQI_{adj. calf circumference} (<0.75 for men, <0.25 for women).

Conclusion: This study introduces MQI_SF-BIA, MQI_{calf circumference}, and MQI_{adj. calf circumference} as future potential surrogate methods for computing MQI in clinical practice when other robust procedures are unavailable, pending further validation.