Patterns of prevention effectiveness in postoperative neurocognitive disorder and delayed neurocognitive recovery research: a systematic review with meta-regression of randomised trials.

BACKGROUND

Postoperative neurocognitive disorder and delayed neurocognitive recovery (pNCD/dNCR) are common yet unresolved complications after surgery.

METHODS

We conducted a systematic literature search in resources of Ovid MEDLINE, EMBASE, Web of Science, and ClinicalTrials.gov and multivariable meta-regression analyses of RCTs to identify trial-level characteristics associated with prevention effectiveness in pNCD/dNCR research. Trials investigating pNCD/dNCR prevention in adult surgical patients were eligible. Trials performed in paediatric patients or assessing cognitive changes on the same day of surgery were excluded. Effectiveness associated with trial-level characteristics was assessed using ratio of odds ratio (OR) and 95% confidence interval (CI).

RESULTS

We analysed 187 eligible trials. Trials originating from the USA/Canada (ratio of OR, 3.04; 95% CI, 1.62-5.73; P=0.001), Europe/Australia/New Zealand (1.58; 1.04-2.40; P=0.033), and other regions (2.0; 1.19-3.36; P=0.009) were associated with reduced effectiveness compared with trials from China. Higher pNCD/dNCR incidence in control groups was associated with greater effectiveness (0.98; 0.97-0.99; P<0.001). Trials involving volatile anaesthetics (2.12; 1.16-3.86; P=0.014) were associated with reduced effectiveness compared with dexmedetomidine and abdominal surgery, respectively. Registered trials exhibited enhanced effectiveness (0.69; 0.50-0.95; P=0.022), whereas those with power analyses reported reduced effectiveness (1.43; 1.06-1.94; P=0.021). Trials with a high risk of bias in the selection of the reported result were associated with reduced effectiveness (2.99; 1.04-8.59; P=0.041). Dexmedetomidine was the most studied intervention, showing potential benefits, though evidence certainty was very low.

CONCLUSIONS

Trial-level characteristics were significantly associated with prevention effectiveness in pNCD/dNCR research. Identifying and addressing the underlying causes of regional differences might enhance the quality and consistency of future trials on a global level.

SYSTEMATIC REVIEW PROTOCOL: PROSPERO (CRD42024543584).