ICU sedation, delirium & recovery
Rethinking Muscle Wasting in Critical Illness: A Systematic Review and Meta-Analysis of Myofiber Size and Protein Turnover
Authors' conclusion
While myofiber size is significantly lower in patients with critical illness, pooled analyses show no significant differences in muscle protein synthesis compared with non-ICU controls, whereas protein degradation markers are consistently higher.
Study context
- Population
- Adults with critical illness with skeletal muscle biopsies75 studies
- Participants
- 2,023 vs 642
- Comparison
- Adults with critical illness vs controls
- Patientsn = 2,023
- Controlsn = 642reference
- Outcome
- Myofiber cross-sectional area and protein turnover (mean differences (MDs) vs controls)
Methodological detailsrandom-effects meta-analyses, Biopsies mainly from vastus lateralis (64 [85%] studies), during first ICU week (50% of studies) and post-ICU (9%)
- Random-effects meta-analyses
- Biopsies mainly from vastus lateralis (64 [85%] studies), during first ICU week (50% of studies) and post-ICU (9%)
Pooled result
As reported in the abstract
Myofiber cross-sectional area (6 studies; n = 100 patients, 193 controls)
Patients vs ControlsMD, µm 2 (95% CI)P value
Before ICU discharge
−689(−1265 to −113)
P = 0.02After ICU discharge
−775(−1512 to −37)
P = 0.04Further pooled results
| Outcome | MD (%/hr) (95% CI) | P value | |
|---|---|---|---|
| Protein synthesis (7 studies; n = 126 patients, 61 controls) | 0.007 (−0.010 to 0.027) | P = 0.36 | |
| −0.0200.020.04Difference, %/hr (linear scale) |
Protein degradation pathway markers (11 studies; n = 439 patients, 163 controls)
- Significantly higher in patients (SMD range)
- 0.5-1.7
Descriptive biological findings
- Predominant type II myofiber atrophy with necrosis and structural degeneration, mitochondrial dysfunction, inflammatory/fibrotic changes, upregulated ubiquitin-proteasome/autophagy pathways
Original publication
Rethinking Muscle Wasting in Critical Illness: A Systematic Review and Meta-Analysis of Myofiber Size and Protein Turnover. Crit Care Med. Published 7 August 2026. doi:10.
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