Association between augmented enteral protein and muscle mass attenuation in critically ill patients: A sub-study of...

Critically ill patients experience muscle wasting, impacting recovery. The associations between augmented enteral protein and muscle mass, strength, physical function, and quality of life are uncertain.

We performed a sub-study in adult TARGET Protein participants from two sites between 23/11/2022-23/05/2023. Our exposure of interest was enteral formula with augmented protein (100 g protein/L) and comparator usual protein formula (63 g protein/L), which were isocaloric. Our primary outcome was the change in quadriceps muscle layer thickness from Days 1 to 7, determined by ultrasonography and compared between groups. Our secondary outcomes were group differences in handgrip strength, change in physical function, and quality of life. Data are numbers (%), mean (standard deviation), and differences with 95% confidence intervals (CI).

Seventy-two patients were included (augmented protein n = 46, 61 (16)y, 65% male; usual protein n = 26, 56 (16)y, 46% male), 56 had primary outcome data (augmented protein n = 35; usual protein n = 21). Delivered protein was higher with augmented protein (1.2 (0.4) vs 0.8 (0.3) g/kg/day). Quadriceps muscle layer thickness decreased in both groups, with change from Days 1 to 7 similar (0.01 cm; 95% CI, -0.27, 0.28; P = 0.970). Left handgrip strength at ICU discharge and quality of life at Day 90 were similar. Augmented protein was associated with greater right handgrip strength at ICU discharge (6.23; 95% CI, 0.67, 11.79) and was associated with greater decline in physical function at ICU discharge (-15.00; 95% CI, -19.75, -10.25), but not at Day 90.

No clear difference was detected in quadriceps muscle layer attenuation over 7 days between augmented enteral protein and usual protein.

Australian New Zealand Clinical Trials Registry identifier: ACTRN12622001465741.