Risk of second hip fracture persists for years after initial trauma

Abstract

Background: Secondary prevention often targets women who suffer from higher rates of second hip fracture than men, especially in the early years after first fracture. Yet, the occurrence of second hip fracture by certain times also depends on the death rate, which is higher in men than women. We compared the risk of sustaining second hip fracture by a certain time between women and men remaining alive at that time.

Methods: We retrieved 38,383 hospitalization records of patients aged 60 years or older, who were discharged alive after admission for hip fracture surgery between 1990 and 2005 in British Columbia, Canada. The outcome variable was the time to a subsequent hip fracture.

Results: During ten years of follow-up, 2,902 (8%) patients sustained a second hip fracture, and 21,428 (56%) died before sustaining a second hip fracture. The risk of second hip fracture in the surviving post-fracture patients was higher in women than in men: 2% vs 2%, 5% vs 4%, 9% vs 7%, 15% vs 13%, and 35% vs 30% at 1, 2, 3, 5, and 10 years after initial trauma, respectively, crude OR=1.25 (95% CI: 1.13-1.39). However, the risk did not differ between women and men after adjustment, OR=1.09 (95% CI: 0.98-1.21).

Conclusions: The risk of second hip fracture persists for at least ten years among hip fracture survivors, and therefore secondary prevention should continue beyond an early post-fracture period. Women and men have similar risks of second hip fracture and both should be considered for secondary prevention.

Keywords: Ccompeting risks; Conditional probability; Death rate; Hip fracture; Secondary prevention; Time to subsequent hip fracture.