Amount of Muscle Mass During ICU Admission May Be Linked to Survival

Pectoralis muscle area (PMA) of patients admitted to a medical intensive care unit (MICU) is associated with survival both during and after critical illness, but is unable to predict the regaining of an independent lifestyle after hospital discharge, according to study results published in CHEST.

Investigators sought to examine the association of skeletal muscle and fat mass at ICU admission with survival and disability at hospital discharge. A total of 401 patients admitted to the ICU at Albany Medical Center in New York were evaluated with respect to PMA and subcutaneous adipose tissue (SAT). In all participants, PMA and SAT were determined by computed tomography (CT) scanning at the time of ICU admission, and were later correlated with clinical outcomes.

Study enrollment occurred between November 2015 and February 2017. Study eligibility requirements included age ≥18 years, admission to the MICU, a chest CT scan within the first 24 hours of hospital admission, and the likely need for an ICU stay of >24 hours.

Larger PMA at admission was associated with significantly better outcomes, including higher rates of 6-month survival (odds ratio [OR], 1.03 per cm² increase in PMA; 95% CI, 1.01-1.04; P <.001), lower rates of hospital mortality (OR, 0.96 per cm² in PMA; 95% CI, 0.93-0.98; P< .001), and more ICU-free days (slope, 0.044±0.019 days per cm² PMA; P =.021). In contrast, SAT was not significantly associated with any of the measured outcomes.

On the basis of multivariable analyses, PMA continued to be associated with survival and ICU-free days, whereas SAT continued not to demonstrate any association with survival or other outcomes. Moreover, PMA was not significantly associated with the regaining of independence by the participants at the time of hospital discharge (OR, 0.99 per cm² PMA; 95% CI, 0.98-1.01; P =.56).

The investigators concluded that additional research on muscle turnover in patients in the ICU is warranted to clarify whether better muscle mass can lead to improved outcomes. In fact, muscle mass before admission may serve as a useful biomarker with respect to important outcomes in the ICU. SAT, however, is not associated with survival or disability both during and after critical illness.

Reference

Jaitovich A, Khan MMHS, Itty R, et al. ICU admission muscle and fat mass, survival and disability at discharge: a prospective cohort study [published online October 27, 2018]. CHEST. doi:10.1016/j.chest.2018.10.023.