Bone Abstracts

Several studies have shown a higher mortality after hip fracture but the reasons and the duration of the excess risk is not well understood. We aimed to determine whether there exists a higher mortality after hip fracture when controlling for genetic constitution, environmental and life-style risk factors, and comorbidity. All 286 identical Swedish twin pairs discordant for hip fracture (1972–2010) were identified by use of the National patient register and the Swedish twin registry, the largest in the world. Comorbidity and lifestyle information was retrieved by registers and questionnaire information by surveys within the twin registry done before the hip fracture event. We used intrapair Cox’s regression to compute multivariable adjusted hazard ratios (HRs) for death. During 3877 person-years of follow-up, 244 of 572 twins died. Through the first year after hip fracture, the rate of death increased fourfold in women (HR 4.46; 95% CI 1.47–13.56) and sixfold in men (HR 6.51; 95% CI 1.37–30.97). The higher rate in women only persisted during the first year after hip fracture (HR after 1 year 0.97; 95% CI 0.64–1.48), whereas the higher risk in men lasted 5 years with a successive decline in risk during this 5-year period. On average, the hip fracture contributed to 0.9 years of life lost in women (95% CI 0.1–1.7) and 2.7 years in men (95% CI 1.7–3.7). The potential years of life lost due to the hip fracture was especially pronounced in older men (>75 years), with an average loss of 47% (95% CI 31–61) of the expected remaining lifetime. In conclusion, the impact on mortality by a hip fracture event per se lasts 1 year in women and 5 years in men, halving the expected survival in older men which corresponds to the mortality of non-curatively treated prostate cancer with distant metastases.