The association between preoperative anxiety and chronic post-surgical pain after general anaesthesia, a systematic review and meta-analysis.

Background: Chronic post-surgical pain (CPSP) is a burden for both patients and healthcare, yet current treatment options are insufficient. Previous studies indicate preoperative anxiety as a risk factor for developing CPSP, yet no high-quality review exists. This study aims to systematically review the relationship between increased preoperative anxiety and the incidence of new CPSP. Methods: Four databases were used to identify relevant studies for a systematic review and meta-analysis. Inclusion criteria included adult patients undergoing surgical procedures under general anaesthesia, measuring preoperative anxiety with validated tools, and postoperative pain at least 3 months after surgery. Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines were followed, and a risk of bias analysis was performed. Results: Of the 233 studies retrieved, 26 studies were included in the systematic review. Following risk of bias analysis, 23 papers were included in the meta-analysis. A correlation was found between preoperative anxiety and CPSP, with a standardised mean difference of 0.31 (95% confidence interval 0.20-0.41). High heterogeneity was observed, which was attributed to several possible confounding factors. Subgroup analysis did not alter this outcome. When translating the outcome to a relevant scale, we observed an increase in numeric rating scale pain of 0.34 for patients experiencing preoperative anxiety. Conclusions: There is moderate-quality evidence indicating a positive association between preoperative anxiety and CPSP, where an increase in preoperative anxiety correlates with an increased incidence of CPSP. More research is needed to identify specific patients that would benefit from treating preoperative anxiety and thus potentially preventing CPSP. Systematic review protocol: PROSPERO (CRD42024513479).