Hip fracture causes excess mortality owing to cardiovascular and infectious disease in institutionalized older people: a prospective 5-year study

Abstract

An increasing risk of death after hip fracture has been well documented, but the duration and causes remain unclear, especially in very frail older people. This is a nested case-control study of 229 hip fracture cases and 229 controls matched by age, gender, institution type, and follow-up period from a cohort of 2005 institutionalized older people. The residents were assessed at baseline and followed up for hip fracture and death for at least 5 years. Time to death was measured from the same time for each case (time of the hip fracture) and the matched control. The study sample consisted of 90 males and 368 females with a mean age of 86 years (range 67 to 102 years). The hazard ratio (HR) of death for the cases compared with the controls was 3.09 [95% confidence interval (CI) 1.83-5.22, p < .001] for the first 3 months, 1.99 (95% CI 1.13-3.51, p = .02) for the period of 3 to 9 months, and 0.88 (95% CI 0.64-1.22, p = .46) for the period beyond 9 months following a fracture, after adjusting for age, gender, institution type, weight, immobility, cognitive function, comorbidities, and number of medications. The main causes of the excess mortality in the first 9 months were infections (HR = 6.66, 95% CI 1.95-22.77, p = .002) for females and cardiac disease (HR = 2.68, 95% CI 1.39-5.15, p = .003) for both males and females. Bisphosphonate use was associated with a reduction in mortality after hip fracture (p = .002). Intensive medical supervision to reduce cardiovascular and infective complications should be provided for frail older people with recent hip fracture to reduce mortality.