Incidence and prevalence of perioperative neurocognitive disorders in older surgical patients: a systematic review and meta-analysis protocol

Prospective protocol for a two-stage study. Stage 1: systematic review and meta-analysis of the incidence and prevalence of perioperative neurocognitive disorders (PND, formerly postoperative cognitive dysfunction, POCD) in patients aged 60 years and older undergoing surgery under anaesthesia, conducted and reported according to PRISMA-P. Databases: PubMed (MEDLINE), Embase, Web of Science Core Collection, Cochrane CENTRAL, PsycINFO, CNKI and ClinicalTrials.gov, from inception with no restriction on publication date or language. Primary outcomes are PND prevalence/incidence at ≤7 days, 1 month, 3 months, 6 months and 12 months; a secondary outcome is the relative risk of mortality. Stage 2 applies the pooled parameters to a global burden-of-disease model, estimating years lived with disability, years of life lost and disability-adjusted life years (DALYs) stratified by GBD region, Socio-demographic Index quintile, age and sex, with uncertainty propagated by Monte Carlo simulation (1,000 draws) and reported according to the GATHER statement. Registered with PROSPERO: CRD420261553380.