Changes in body composition in the year following critical illness: A case-control study

Area of Science:

• Critical Care Medicine
• Body Composition Analysis
• Metabolic Health

Background:

• Intensive Care Unit (ICU) survivors often experience long-term health consequences, including altered body composition.
• Understanding post-ICU body composition changes is crucial for recovery and rehabilitation.
• Dual x-ray absorptiometry (DXA) is a reliable method for assessing lean and fat mass.

Purpose of the Study:

• To quantify changes in body composition (lean and fat mass) in ICU survivors one year after discharge.
• To compare the body composition trajectory of ICU survivors with age- and sex-matched population controls.
• To identify potential long-term metabolic effects of critical illness.

Main Methods:

• Prospective observational study design.
• Dual x-ray absorptiometry (DXA) used to measure hip and spine lean and fat mass at ICU discharge and 1-year follow-up.
• Comparison with 64 age-sex-height matched controls from the Geelong Osteoporosis Study using multivariable linear regression.

Main Results:

• ICU survivors showed greater annual increases in lean mass (+0.92 kg) and fat mass (+2.50 kg) compared to controls.
• At 1-year follow-up, ICU survivors had significantly lower lean mass (-0.96 kg) and higher fat mass (+6.79 kg) than controls.
• Participants had a median age of 68.8 years, with an average ICU stay of 6.5 days and mechanical ventilation of 87 hours.

Conclusions:

• Mechanically ventilated ICU patients gain lean mass in the year post-critical illness but do not reach population-based levels.
• Significant differences in lean and fat mass persist between ICU survivors and controls at one year.
• Further investigation is required to understand factors influencing muscle and fat mass changes after critical illness.