Gender Differences in Mortality After Hip Fracture: The Role of Infection

Abstract

Possible explanations for the observed gender difference in mortality after hip fracture were examined in a cohort of 804 men and women. Mortality during 2 years after fracture was identified from death certificates. Men were twice as likely as women to die, and deaths caused by pneumonia/influenza and septicemia showed the greatest increase. Men are more likely to die after hip fracture than women. Gender differences in predisposing factors and causes of death have not been systematically studied. Participants (173 men and 631 women) in the Baltimore Hip Studies cohort enrolled in 1990 and 1991, at the time of hospitalization for hip fracture, were followed longitudinally for 2 years. Cause-specific mortality 1 and 2 years after hip fracture, identified from death certificates, was compared by gender and to population rates. Men were twice as likely as women to die during the first and second years after hip fracture (odds ratio [OR], 2.28; 95% CI, 1.47, 3.54 and OR, 2.21; 95% CI, 1.48, 3.31). Prefracture medical comorbidity, type of fracture, type of surgical procedure, and postoperative complications did not explain the observed difference. Greatest increases in mortality, relative to the general population, were seen for septicemia (relative risk [RR], 87.9; 95% CI, 16.5, 175 at 1 year and RR, 32.0; 95% CI, 7.99, 127 at 2 years) and pneumonia (RR, 23.8; 95% CI, 12.8, 44.2 at 1 year and RR, 10.4; 95% CI, 3.35, 32.2 at 2 years). The magnitude of increase in deaths caused by infection was greater for men than for women in both years. Mortality rates for men and women were similar if deaths caused by infection were excluded (3.46 [1.79, 6.67] and 2.47 [1.63, 3.72] at 1 year and 0.96 [0.48, 1.91] and 1.26 [0.80, 1.98] at 2 years). Deaths related to infections (pneumonia, influenza, and septicemia) seem to be largely responsible for the observed gender difference. In conclusion, an increased rate of death from infection and a gender difference in rates persists for at least 2 years after the fracture.