The diagnostic accuracy of blood biomarkers for sarcopenia, sarcopenic obesity, and osteosarcopenia: a meta-analysis

BACKGROUND AND AIMS: Sarcopenia is the accelerated loss of skeletal muscle mass and function associated with ageing. Sarcopenia screening consists of body composition imaging and physical function tests; however, these tests can be burdensome and inconsistent. This review aimed to synthesise the available evidence on the diagnostic accuracy of blood biomarkers for sarcopenia (and related conditions). METHODS: Literature searches were conducted using medical subject headings and words relevant to sarcopenia, biomarkers, and diagnostic accuracy. There were no restrictions on the population. Studies that used correlation or regression analyses, or had no control group, were excluded. Pooled estimates of sensitivity, specificity, and area under the curve (AUC) were calculated. RESULTS: The searches identified 150 studies assessing 170 unique biomarkers, and 20 had sufficient studies for meta-analysis. The serum creatinine-cystatin C ratio (CCR) demonstrated pooled sensitivity of 0.69 (95% CI: 0.63-0.75), specificity of 0.74 (95% CI: 0.69-0.80) and AUC of 0.71 (95% CI: 0.68-0.74) (25 studies). Myostatin (10 studies) and irisin (six studies) had pooled sensitivities of 0.76 (95% CI: 0.61-0.87) and 0.74 (95% CI: 0.56-0.86), specificities of 0.71 (95% CI: 0.65-0.76) and 0.72 (95% CI: 0.60-0.81), and AUCs of 0.72 (95% CI: 0.66-0.79) and 0.72 (95% CI: 0.65-0.78), respectively. The diagnostic accuracy of other identified blood biomarkers varied and ranged from fail to excellent. CONCLUSION: This review provides evidence on the use of biomarkers to diagnose sarcopenia, which can inform the development of targeted screening and intervention in research and practice. The integration of biomarker-based diagnostics offers a critical opportunity to reduce the global burden of sarcopenia.