The mortality burden in patients with hip fractures and dementia.

PURPOSE Dementia is strongly associated with postoperative death in patients subjected to hip fracture surgery. Nevertheless, there is a distinct lack of research investigating the cause of postoperative mortality in patients with dementia. This study aims to investigate the distribution and the risk of cause-specific postoperative mortality in patients with dementia compared to the general hip fracture population. METHODS All adults who underwent emergency hip fracture surgery in Sweden between 1/1/2008 and 31/12/2017 were considered for inclusion. Pathological, conservatively managed fractures, and reoperations were excluded. The database was retrieved by cross-referencing the Swedish National Quality Registry for Hip Fracture patients with the Swedish National Board of Health and Welfare quality registers. A Poisson regression model was used to determine the association between dementia and all-cause as well as cause-specific 30-day postoperative mortality. RESULTS 134,915 cases met the inclusion criteria, of which 20% had dementia at the time of surgery. The adjusted risk of all-cause 30-day postoperative mortality was 67% higher in patients with dementia after hip fracture surgery compared to patients without dementia [adj. IRR (95% CI): 1.67 (1.60-1.75), p < 0.001]. The risk of cause-specific mortality was also higher in patients with dementia, with up to a sevenfold increase in the risk cerebrovascular mortality [adj. IRR (95% CI): 7.43 (4.99-11.07), p < 0.001]. CONCLUSIONS Hip fracture patients with dementia have a higher risk of death in the first 30 days postoperatively, with a substantially higher risk of mortality due to cardiovascular, respiratory, and cerebrovascular events, compared to patients without dementia.