Association between prior non-spine non-hip fractures or prevalent radiographic vertebral deformities known to be at least 10 years old and incident hip fracture

Abstract

In this large cohort of elderly women, prior non-spine non-hip fractures and radiographic vertebral deformities >10 years old were modestly associated with incident hip fracture, but the excess risks of hip fracture attributable to those prior fractures and deformities seem to wane over time.

Introduction: Whereas prior clinical fractures and prevalent radiographic vertebral deformities are well-documented predictors of incident hip fracture, the excess risks of incident fractures attributable to those prior fractures and deformities may decrease over time. Current guidelines regarding the assessment of fracture risk do not consider elapsed time since prior fracture or ascertainment of radiographic vertebral deformity.

Materials and methods: We ascertained self-reported history of prior clinical fractures and calcaneal and total hip bone BMD and performed lateral spine radiographs in a cohort of 9516 community-dwelling elderly women who had not had a prior hip fracture. We prospectively followed them to assess incident hip fracture. Prevalent radiographic vertebral deformities were identified at baseline using morphometry, and incident hip fractures were confirmed by review of radiographic reports during three follow-up periods (0-5, >5-10, and >10 years after baseline exam).

Results: Among women who survived for 10 or more years after the baseline exam without having had a hip fracture, a history of non-spine non-hip fracture since age 50 reported at the baseline study examination was associated with a 21% age- and calcaneal BMD-adjusted excess risk (hazard ratio [HR], 1.21; 95% CI, 1.01-1.45) for subsequent incident hip fracture. Baseline radiographic vertebral deformity was associated with a 41% age- and BMD-adjusted excess risk (HR, 1.41; 95% CI, 1.15-1.73) of hip fracture after 10 years of follow-up. In comparison, the age- and BMD-adjusted HRs of incident hip fracture during the first 5 years of follow-up associated with prior non-spine non-hip fractures reported at the baseline study exam and prevalent radiographic vertebral deformities were 1.70 (95% CI, 1.30-2.22) and 2.10 (95% CI, 1.58-2.78), respectively.

Conclusions: Self-reported prior non-spine non-hip fractures and prevalent radiographic vertebral deformities known to be at least 10 years old are modestly associated with incident hip fracture. The association between these predictor fractures and subsequent hip fractures seems to wane with increased time after ascertainment of the predictor fracture. Hip fracture risk assessment strategies incorporating prior fracture history should also consider elapsed time since those prior fractures.