S100β as a potential biomarker of incident delirium: a systematic review and meta-analysis

Delirium is an acute and fluctuating change in cognition, attention and consciousness, defined as an acute neuropsychiatric syndrome, but mechanism is extremely complex and still not well understood. Recently, the S100 calcium-binding protein B protein (S100β) has received attention in the biomarker research area of delirium. This meta-analysis was designed to investigate the relationship between S100β levels and delirium.

We conducted a systematic literature search of MEDLINE (via PubMed search engine), Ovid, EMBASE, and Cochrane Library electronic databases for case-control studies measuring S100β levels from delirium and no delirium controls. Extracted data were analyzed with STATA. The standardized mean difference (SMD) and the 95% confidence interval (95% CI) were calculated using a random effect model.

We identified ten eligible studies including 1739 patients. The pooled SMD showed significant difference in S100β between delirium patients and control (SMD: 0.88; 95% CI: 0.31 to 1.46), but there was high heterogeneity (I2: 95.9%; P=0.000). Further subgroup analysis showed significant differences in cerebrospinal fluid (CSF) S100β (SMD: 0.87; 95% CI: 0.20 to 1.53) and low heterogeneity (I2: 59.8%; P=0.115).

This meta-analysis provides evidence that serum S100β seems to be of limited value as a biomarker of delirium, but CSF S100β elevation may be more meaningful.