[Retracted] Correlation Analysis of Inflammatory Markers CRP and IL‐6 and Postoperative Delirium (POD) in Elderly Patients: A Meta‐Analysis of Observational Studies

Abstract

Background. Postoperative delirium (POD) is very common in the elderly surgical population, and its occurrence is associated with multiple factors such as preoperative, intraoperative, and postoperative factors, and the increase of serum inflammatory markers such as C-reactive protein (CRP) and interleukin-6 (IL-6) is considered to be associated with the occurrence of POD, but the results of multiple studies are inconsistent. In this study, we investigated the correlation between inflammatory markers CRP and IL-6 and POD in elderly patients by literature search and meta-analysis. Methods. We searched PubMed, Web of Science, the Cochrane library, Embase, Ovid, and Springer Link for cohort studies or case-control studies that investigated the factors involved in the occurrence of POD, used the Newcastle-Ottawa Scale (NOS) to assess the quality of the selected literature, and combined the differences in serum CRP and IL-6 levels between POD and non-POD patients after surgery to evaluate the predictive value of CRP and IL-6 for the occurrence of POD. Results. This research comprised 16 papers for quantitative analysis, with a total of 2967 patients, 758 with POD and 2209 with non-POD. There were 16 cohort studies (100%) and 0 case-control studies (0%) across all the collected literatures; there were 15 prospective cohort studies and 1 retrospective cohort research. A meta-analysis revealed a statistically significant difference in serum IL-6 levels between POD patients after surgery and non-POD patients [ MD = 115.68 , 95% CI (25.70, 206.66), Z = 2.52 , P = 0.012 ], as well as a statistically significant difference in serum CRP levels [ MD = 27.67 , 95% CI (12.77, 42.58), Z = 3.64 , P = 0.0003 ]. Discussion. Early after surgery, serum IL-6 and CRP levels were considerably higher in POD patients than in non-POD patients, indicating that early serum inflammatory variables are likely to be predictors of POD. After surgery, the levels of the aforementioned inflammatory factors should be actively monitored to forecast the emergence of delirium, and active treatment should be used to limit the creation and release of the aforementioned inflammatory factors.

Risk factors for hypoactive delirium in patients with nontraumatic ARDS: a prospective observational study

“…Our study showed that higher blood IL-6 levels were associated with a greater incidence of hypoactive delirium, consistent with the findings of other researchers. Huang et al 26 and Chen et al 25 found that IL-6 was an independent risk factor for postoperative delirium. An increasing amount of evidence suggests that high systemic plasma IL-6, which can disrupt the integrity of the blood–brain barrier (BBB), increase solute permeability, and alter brain metabolism, directly causes neuronal apoptosis 10 .…”

Effect of esketamine on postoperative analgesia and postoperative delirium in elderly patients undergoing gastrointestinal surgery

“…Systemic inflammatory mediators increased significantly following surgery and remained elevated throughout the postoperative period. Studies have shown that serum IL-6 and CRP levels in patients with POD are higher than those in patients without POD [ 15 ]. During the early postoperative period, an increase in peripheral blood IL-6 concentration is associated with a higher risk of postoperative delirium [ 16 – 18 ].…”

Inflammatory biomarkers and delirium: a Mendelian randomization study

“…High serum IL-6 or C-reactive protein (CRP) levels were reported to increase the risk of postoperative delirium (POD) in three meta-analyses of cohort or case–control studies. The effects of serum IL-8, IL-10, and tumor necrosis factor-α (TNF-α) on the risk of POD were lost in pooled analyses (Liu et al's., 2018 ; Noah et al, 2021 ; Huang et al, 2022 ). Conversely, in a recent prospective cohort study, multivariate logistic regression analysis showed that perioperative increases in plasma IL-10 and neutrophil gelatin enzyme-related lipids were associated with POD, but CRP, IL-1β, and IL-6 were not (Yang et al, 2022 ).…”