Cytokines and inflammatory biomarkers and their association with post-operative delirium: a meta-analysis and systematic review.

Delirium is a prevalent cognitive disorder among older patients and a common phenomenon following major surgical procedures. This study aimed to identify the significant proteomic biomarkers and examine their association with postoperative delirium (POD). Four electronic databases were used to identify the published articles between 1st January 2000 and 31st December 2023. Among the included 40 studies, the meta-analysis investigated 13 potential cytokines and inflammatory biomarker proteins linked with postoperative delirium. The Hedge's g standardized mean difference (SMD) was applied to calculate the effect size, with 95% confidence intervals (CIs), under the fixed effect or random effect model based on the heterogeneity index of I2. Patients with POD exhibited significantly higher elevated levels of inflammatory biomarkers IL-6 (SMD = 1.45), CRP (SMD = 1.26), GFAP (SMD = 1.15), IL-1B (SMD = 0.95), IL-10 (SMD = 0.57), IL-8 (SMD = 0.56), MCP-1 (SMD = 0.39), and NFL (SMD = 0.44), suggesting that these proteins may play an inevitable role in delirium-associated cytokines and inflammatory response, development and progression of delirium. Conversely, a reduction in IGF-1 protein level (SMD =  - 0.24) was also significantly associated with POD, suggesting a potential vulnerability to delirium. This study paves the way for future research aimed at early diagnosis, personalized treatment, and the development of novel therapeutic strategies to manage delirium effectively.