Long-term sex differences in all-cause and infection-specific mortality post hip fracture

Mortality rates among men are double that of women in the first 2 years after hip fracture and may be related to more infections. Research has only examined differences in short-term mortality after hip fracture. Thus, the objective was to determine if long-term all-cause mortality and infection-specific mortality rates are higher in men compared to women. Data come from a prospective cohort study (Baltimore Hip Studies 7th [BHS-7]) with up to 10.2 years of follow-up (2006-2018). The participants were selected from eight acute care hospitals in the 25-hospital BHS network. Enrolled women were frequency-matched (1:1) to men on timing of admission for hip fracture that yielded an analytic sample size of 300 participants (155 women, 145 men). Associations between sex and mortality were analyzed using Cox proportional hazard models and cause-specific Cox models adjusted for age, cognition, body mass index, pre-fracture lower extremity activities of daily living limitation, depressive symptoms, and comorbidity. Participants had a mean age of 80 years, 48% (n = 145) were men and the median follow-up was 4.9 (interquartile range = 2.3-8.7) years. Over the follow-up period after hospital admission for hip fracture, 237 (79.0%) participants died of all causes (132 men and 105 women) and 38 (12.7%) died of infection-specific causes (25 men and 13 women). Men had significantly higher rates of all-cause mortality [hazard ratio (HR) = 2.31(95% confidence interval [CI] 2.02-2.59)] and infection-specific mortality (HR = 4.43, CI 2.07-9.51) compared to women. Men had a two-fold higher rate of all-cause mortality and four-fold higher rate of infection-specific mortality compared to women over a follow-up period of up to 10.2 years. Findings suggest that interventions to prevent and treat infections, tailored by sex, may be needed to narrow significant differences in long-term mortality rates between men and women after hip fracture.