Association between dementia and mortality in the elderly patients undergoing hip fracture surgery: a meta-analysis

OBJECTIVE: This study was designed to verify the association between dementia and mortality in the elderly undergoing hip fracture surgery, and assessed the mortality of patients with dementia after hip fracture surgery. MATERIAL AND METHODS: PubMed, Embase, and Web of Science were searched until April, 2018 without language restrictions. Two reviewers selected related studies, assessed study quality, and extracted data independently. Risk ratios (RRs) with 95% confidence intervals (CI) were derived using random-effects model throughout all analyses. The endpoints included 30-day, 6-month, 1-year, and more than 1-year mortality. This meta-analysis was performed following PRISMA statement and carried out by using stata14.0 software. RESULTS: Dementia significantly increased postoperative mortality of patients suffered from hip fracture in 30-day [RR = 1.57, 95% CI (1.29, 1.90), P<0.00], 6-month [RR = 1.97, 95% CI (1.47, 2.63), P<0.00], 1-year [RR = 1.77, 95% CI (1.54, 2.04), P<0.00], and more than 1-year follow up [RR = 1.60, 95% CI (1.30, 1.96), P<0.00] respectively. The mortality of dementia patients after hip fracture surgery in 30-day [ES = 12%, 95% CI (8%, 15%)], 6-month [ES = 32%, 95% CI (17%, 48%)], 1-year [ES = 39%, 95% CI (35%, 43%)], and more than 1-year follow up [ES = 45%, 95% CI (32%, 58%)]. CONCLUSIONS: Our meta-analysis demonstrated that the mortality of patients with dementia suffered from hip fracture surgery is 12%, 32%, 39%, and 45%, and dementia increased 1.57, 1.97, 1.77, and 1.60-fold mortality in patients undergoing hip fracture surgery in 30-day, 6-month, 1-year, and more than 1-year follow up respectively.