Excess mortality attributable to hip-fracture: a relative survival analysis

Abstract

Introduction: Individuals with hip fracture are at substantially increased risk of mortality. The aim of this study was to estimate the excess mortality attributable to hip fracture in elderly men and women.

Methods: The Dubbo Osteoporosis Epidemiology Study was designed as a prospective epidemiologic investigation, in which more than 2000 men and women aged 60+ as of 1989 had been followed for 21 years. During the follow-up period, the incidence of atraumatic hip fractures was ascertained by X-ray reports, and mortality was ascertained by the New South Wales Birth, Death and Marriage Registry. Relative survival ratios were estimated by taking into account the age-and-sex specific expected survival in the general Australian population from 1989 to 2010.

Results: During the follow-up period 151 women and 55 men sustained a hip fracture. Death occurred in 86 (57%) women and 36 (66%) men. In women, the cumulative relative survival post hip-fracture at 1, 5 and 10 years was 0.83 (95% confidence interval (CI) 0.76-0.89), 0.59 (95% CI 0.48-0.68), and 0.31 (95% CI 0.20-0.43), respectively; in men, the corresponding estimates of relative survival were: 0.63 (95% CI 0.48-0.75), 0.48 (95% CI 0.32-0.63), and 0.36 (95% CI 0.18-0.56). On average post hip-fracture women died 4 years earlier (median: 4.1, inter-quartile range (IQR) 1.7-7.8) and men died 5 years earlier (median = 4.8, IQR 2.4-7.0) than expected. For every six women and for every three men with hip fracture one extra death occurred above that expected in the background population.

Conclusion: Hip fracture is associated with reduced life expectancy, with men having a greater reduction than women, even after accounting for time-related changes in background mortality in the population. These data underscore that hip fracture is an independent clinical risk factor for mortality.

Keywords: Bone mineral density; Hip fracture; Mortality; Osteoporosis; Relative survival.