Short time-frame from first to second hip fracture in the Funen County Hip Fracture Study.

INTRODUCTION: Hip fracture patients represent a frail group of elderly with increased morbidity and mortality. The aim of this study was to evaluate the occurrence and distribution of a second hip fracture in the time interval between the first and the second hip fracture.
METHODS: All incident hip fractures in residents of Funen County, Denmark, from 1994 through 2004 were recorded. Verified fractures were sequenced within each patient using the unique Danish identification numbers.
RESULTS: In total, 9990 incident hip fractures occurred: 9122 first hip fractures and 868 (8.7%) second fractures. Within the first year after the first hip fracture, the incidence rate of the second fracture in men decreased from 73 per 1000 person-years (py) during the first 3 months to 8 per 1000 py at 12 months; in women, it decreased from 116 per 1000 py during the first 3 months to 15 per 1000 py at 12 months. Of all the second fractures, 50% occurred within 12 months in men and within 19 months in women.
CONCLUSIONS: Few hip fracture patients experience a second hip fracture and when they do, it is within a short time-frame from the first. The risk of sustaining a second hip fracture is high during the first 12 months following the first hip fracture, decreasing to a level equal to or below the incidence of the first hip fracture after this 12-month period. Preventive strategies at the time of the first hip fracture should therefore aim at immediate effects, as interventions with effects after 12 months (men) and 19 months (women) bypass at least 50% of the fractures.