CT-Assessed Sarcopenia Combined with Laboratory Inflammatory Markers for Outcome Prediction in Critically Ill, Pulmonary, and Geriatric Patients: A Systematic Review and Meta-Analysis.

Background: Sarcopenia, assessed via computed tomography (CT), is an emerging prognostic tool in critically ill, pulmonary, and geriatric patients. Laboratory inflammatory markers such as C-reactive protein (CRP), interleukin-6 (IL-6), and neutrophil-to-lymphocyte ratio (NLR) are routinely obtained in these populations. Whether CT-assessed sarcopenia combined with laboratory markers offers superior prognostic accuracy over either measure alone remains unclear. Objectives: To systematically evaluate the prognostic value of CT-assessed sarcopenia, alone or combined with laboratory inflammatory/nutritional markers, for predicting mortality, mechanical ventilation duration, and ICU length of stay in critically ill, pulmonary, and geriatric patients. Methods: MEDLINE/PubMed, Scopus, Embase, and Cochrane Library were searched from inception to December 2024. Observational studies (prospective or retrospective cohorts, case-control) that reported CT-based sarcopenia assessment alongside at least one laboratory inflammatory marker and at least one clinical outcome were included. Two reviewers independently screened studies, extracted data, and assessed methodological quality using the Newcastle-Ottawa Scale (NOS). Random-effects meta-analysis was performed; heterogeneity was assessed using the I² statistic. Results: Twenty-five studies encompassing 12,347 patients were identified. The pooled odds ratio for mortality in sarcopenic versus non-sarcopenic patients was 2.28 (95% CI: 1.83-2.83; I² = 22.1%) across critically ill ICU cohorts. In COVID-19 pulmonary populations, pooled OR for in-hospital mortality with low skeletal muscle mass was 5.84 (95% CI: 1.07-31.83). CT-derived muscle measurements correlated inversely with CRP (r = -0.315), fibrinogen (r = -0.392), D-dimers (r = -0.363), and WBC count (r = -0.287). Combined CT-sarcopenia and inflammatory marker models outperformed conventional scoring systems (APACHE II, SOFA, CURB-65, PSI). Conclusions: CT-assessed sarcopenia, when integrated with laboratory inflammatory markers, provides a robust, mechanistically grounded, and clinically accessible multimodal prognostic framework across critically ill, pulmonary, and geriatric populations.