Postoperative delirium after hip surgery is a potential risk factor for incident dementia: A systematic review and meta-analysis of prospective studies

Background: Although a few trials have explored the relationship between postoperative delirium (POD) and incident dementia in patients with hip surgery, the numbers of participants in each study are relatively small. Thus, we performed a meta-analysis to examine whether POD after hip surgery is a risk factor for incident dementia. Methods: Six prospective cohort studies investigating the development of incident dementia in patients with POD after hip surgery were retrieved from PubMed, Embase, and the Cochrane Library. We performed a pairwise meta-analysis using fixed- and random-effect models. Results: POD significantly increased the risk of incident dementia and cognitive decline (overall odds ratio [ORs] = 8.957; 95 % confidence interval [CI], 5.444-14.737; P < 0.001 in fixed-effects model; overall ORs = 8.962; 95 % CI, 5.344-15.029; P < 0.001 in random-effects model). A publication bias was not evident in this study. Conclusions: Our meta-analysis revealed that POD after hip surgery is a risk factor for incident dementia. Early identification of cognitive function should be needed after surgery and appropriate prevention and treatment for dementia will be required, especially in cases with POD.