Muscle strength trajectories and outcomes in critically ill patients: A prospective multicentre cohort study

Objectives

To investigate the trajectories and determinants of muscle strength in ICU patients and their impact on 1-, 6-, and 12-month mortality outcomes.

Design

Prospective multicenter cohort study.

Settings

Ten ICUs across five tertiary hospitals in Fujian Province, China.

Methods

Muscle strength was assessed using handgrip strength at three time points: ICU admission, ICU discharge, and hospital discharge. Group-based trajectory modeling was employed to identify muscle strength trajectories, while multinomial logistic analysis determined predictors based on baseline characteristics. Mortality outcomes were assessed using a Cox proportional hazards model adjusted by inverse probability of treatment weighting.

Results

Among 317 patients, with 37 deaths within 12 months, three muscle strength trajectories were identified: Low-Level Stability (38.17 %), Medium-Level Improvement (47.00 %), and High-Level Improvement (14.83 %). Older age (≥65 years), female gender, prolonged mechanical ventilation, and lower fat-free mass were associated with a higher likelihood of being in the Low-Level Stability group. After adjustment, the Medium-Level Improvement group had a 0.067 times lower 1-month mortality risk (95 % CI: 0.005–0.825) compared to the Low-Level Stability group, with no significant differences at 6 or 12 months (P > 0.05).

Conclusions

Three distinct muscle strength trajectories were identified: Low-Level Stability, Medium-Level Improvement, and High-Level Improvement. Older age, female sex, prolonged mechanical ventilation, and lower fat-free mass were strongly associated with the Low-Level Stability group, which had higher 1-month mortality.

Implications for clinical practice

Findings from this study underscore the importance of early identification of Low-Level Stability patients, particularly those who are older, female, require prolonged mechanical ventilation, or have reduced fat-free mass. Tailored early rehabilitation in these high-risk individuals may offer substantial clinical benefit.