Time trends of age-adjusted incidence rates of first hip fractures: a register-based study among older people in Viborg County, Denmark, 1987-1997

Abstract

Introduction: A retrospective cohort study was performed to investigate if incidence rates of first hip fractures are changing in a Danish county. Study material was obtained from an excerpt from a computerized national health register and covers the period 1987-1997.

Methods: First hip fractures were identified through a search 10 years back from the date of admission. To assess the 20-year trend, 1978 data were included. The study period saw inclusion of 3,036 first (1987-1997) and 122 first and recurrent (1978) hip fracture patients aged 50 years and older. Data were analyzed using weighted regression analysis.

Results: Age-adjusted first hip fracture incidence rates increased significantly (P<0.001) for women, men, and pertrochanteric fractures. The rate of increase was 18 [95% confidence interval (CI), 12-25], 8 (95% CI, 4-12), and 10 (95% CI, 7-12) per 100,000 per year for women, men, and pertrochanteric fractures, respectively. The age-adjusted rate for both genders combined was 425 per 100,000 in 1997 (95% CI, 380-470). The incidence of cervical fractures was stable. If the rates of 1978 were included in the analysis, the cervical hip fractures also increased (P<0.001). The weighted average of female-male ratio was a stable 2.6 (95% CI, 2.4-2.8). Cervical-pertrochanteric ratio dropped to 1.2:1 (P<0.001). Mean age at admission rose from 78.9 to 80.8 years.

Conclusion: In conclusion, the results provided support for an increasing incidence of first hip fractures, even when aging of the population was accounted for.