Effect of dementia on all-cause mortality in hip fracture surgery: a retrospective study on a nationwide Korean cohort

OBJECTIVES: We aimed to evaluate the effect of dementia on the 1-year all-cause mortality in elderly patients who underwent hip fracture surgery, using a nationwide cohort in Korea. DESIGN, SETTING, AND PARTICIPANTS: This was a nationwide, retrospective study. Elderly patients (≥60 years) with and without dementia who underwent hip fracture surgery between January 2005 and December 2012 were distinguished using the data from the Korean National Health Insurance Service-Senior cohort. INTERVENTIONS: None. PRIMARY AND SECONDARY OUTCOME MEASURES: The mortality rates with 95% CIs and the impact of dementia on all-cause mortality were calculated using a generalised linear model with Poisson distribution and a multivariable-adjusted Cox proportional hazards model, respectively. RESULTS: Among the 10 833 patients who underwent hip fracture surgery, 13.4% were diagnosed with dementia. During the 1-year follow-up period, 1586 patients with hip fracture without dementia died in 8356.5 person-years (incidence rate (IR)=189.2 per 1000 person-years, 95% CI 179.91 to 198.99), while 340 deaths were confirmed in patients with hip fracture with dementia in 1240.8 person-years (IR, 273.1 per 1000 person-years, 95% CI 244.94 to 304.58). Patients with hip fracture and dementia were 1.23 times more likely to die than those in the control group in the same period (HR=1.23, 95% CI 1.09 to 1.39). CONCLUSION: Dementia is a risk factor for 1-year all-cause mortality after hip fracture surgery. To improve the postoperative outcomes of patients with dementia who have undergone hip fracture surgery, effective treatment models such as multidisciplinary diagnosis and strategic rehabilitation should be established.