Blood astrocyte biomarkers in AD: a systematic review and meta‐analysis

Background We performed a systematic review and meta‐analysis of blood astrocyte biomarkers in Alzheimer's disease (AD). Method MEDLINE and Web of Science were searched without any restrictions on language, time, or study design, for studies reporting blood levels of the astrocyte biomarkers GFAP, YKL‐40, and S100B in AD patients. Pooled effect sizes were determined using Hedge's g method with a random effects model. The review was prospectively registered on PROSPERO (registration number CRD42023458305). Result The search identified 1186 studies; 36 met inclusion criteria (n=3366 AD patients, n=4115 cognitively unimpaired [CU]). Compared to CU individuals, AD patients had significantly higher GFAP and YKL‐40 levels (GFAP effect size 1.15, 95% CI 0.94‐1.36, P