Circulating inflammatory biomarker responses in intervention trials in frail and sarcopenic older adults: A systematic review and meta-analysis

Consistent with the inflammaging concept, cross-sectional associations have been established between inflam-matory biomarkers, frailty and sarcopenia. Less certain is the value of inflammatory markers in monitoring potential anti-inflammatory effects of therapeutic interventions targeted at frailty and sarcopenia. The aims of this systematic review and meta-analysis are to determine if there is a measurable change in inflammatory or immune biomarkers in interventions that improve frailty or sarcopenia and 2. To determine if there are specific inflammatory biomarkers with greater sensitivity to change. In total, 3051 articles were scanned with 16, pri-marily exercise and nutrition interventions, included in the systematic review and 11 in the meta-analysis. At least one of C reactive protein (CRP), interleukin-6 (IL-6) or tumour necrosis factor alpha (TNF-alpha) was reduced in 10 of the 16 review studies but only 3/13 studies reported reductions in multiple markers. CRP, IL-6 and TNF-alpha were individually sensitive to change in 5/11, 3/12 and 5/12 studies respectively. In meta-analyses, there was a positive effect favouring intervention conditions for CRP (SMD =-0.28, p = 0.05) and IL-6 (SMD =-0.28, p = 0.05) but not TNF-alpha (SMD =-0.12, p = 0.48). There were specific issues with the quality of these studies which were not designed with an inflammatory marker as the primary outcome. In conclusion, interventions that improve frailty and sarcopenia can also reduce CRP, IL-6 and TNF-alpha but the literature lacks consistency. We are unable to conclude any one marker as being superior to others.