Risk of Death Persists for Years after Hip Fracture

Kristina Åkesson; Anthony D. Woolf

Disclosures

Abstract and Introduction

Abstract

Patients over the age of 50 have an increased risk of mortality following hip fracture, which is dependent on factors such as health and post-fracture comorbidities. Findings from a meta-analysis highlight the need to improve fracture management through systematic approaches that will also reduce mortality.

Introduction

Hip fracture is generally considered to be the most devastating outcome of osteoporosis. In 1990, 1.66 million hip fractures were reported worldwide—a number that is predicted to rise to 6.3 million by 2050.[1] Low-trauma hip fractures occur mainly in elderly patients, at a mean age of 80. The burden of hip fracture management on both the individual and society is substantial, and is estimated to cost US$21,000 in the first year alone.[2] This expenditure includes direct fracture-treatment costs and social costs owing to functional impairment and increased morbidity. Hip fractures are associated with a high risk of death (particularly during the immediate post-fracture years) that is dependent on both the pre-fracture health status of the patient and the post-fracture medical consequences such as infections, cardiovascular events and thromboembolism.

To elucidate the excess mortality related to hip fracture, Haentjens et al.[3] performed a meta-analysis in which the data from patients with hip fractures were stratified by both sex and time. Overall, 22 cohorts of women and 17 cohorts of men over the age of 50 at the time of hip fracture (and with mortality data available) were included—a total of >500,000 individual patients from registry-based and case-based studies performed in the USA or Europe. The study included both short-term (<2 years) and long-term (≤10 years) analyses. As expected, initial mortality following hip fracture was high. In women, a fivefold increased risk for all-cause mortality during the first 3 months post-fracture was reported, while men had an eightfold increase over the same time period. Excess mortality persisted after hip fracture at each time interval analyzed (1, 2, 5 and 10 years post-fracture). At ≥2 years post-fracture, the relative increase for all-cause mortality was about 2.5-fold and twofold in men and women, respectively, in comparison with the control population—a ratio that was sustained for up to 10 years.

In terms of absolute risk of death, Haentjens et al.[3] created a model based on survival data from US patients with hip fracture, and mortality risk estimates were presented for an 80-year-old individual with a hip fracture. Their findings suggest that a woman who meets the stated criteria has an absolute annual mortality risk of 8%, 11%, 18% and 22% at 1, 2, 5 and 10 years post-fracture, respectively, whereas a man has a corresponding absolute risk of 18%, 22%, 26% and 20%.

This study shows that excess mortality following hip fracture is sustained at a steady rate during 2–10 years of follow-up and is similar for men and women. In the short-term (≤12 months post-fracture) the high excess mortality slowly decreases, but remains higher in men compared with women over the entire first year. This latter finding is a well-known phenomenon—male patients who undergo hip fracture are frailer before fracture than female patients, which inflicts an increased risk in the post-operative and the post-fracture management periods. Comorbidities associated with frailty and mortality in patients with hip fracture include cardiovascular disease, infection, thromboembolism and recurrence of fractures.

Although the meta-analysis by Haentjens et al.[3] was a well-conducted systematic study, it has some limitations (as acknowledged by the authors). The studies included in the analysis were performed at different time-periods; the reported short-term mortality results might, therefore, have been influenced by the overall fracture management at the time when the study was performed. Nevertheless, the presented data are clearly consistent despite the range of observation periods. This study highlights the importance of stratifying risk by sex when analyzing data from patients with hip fracture. However, stratification of the data by patient age at the time of fracture would also have been beneficial, since mortality is clearly influenced by the age of the patient when a fracture occurs.[4] Furthermore, the mean age at occurrence of hip fracture is increasing, and very elderly individuals (>90 years of age) are becoming a proportionally larger subgroup of all patients with hip fracture.[5]

Haentjens et al.[3] provide an important contribution to the knowledge concerning patients with hip fracture and their findings might have clinical utility. Indeed, the implications of this meta-analysis reinforce the recommendations of previous guidelines and initiatives promoting improved management in this vulnerable population of patients.[6,7] The long-term mortality of individuals with hip fracture highlights the need to consider factors at the time of fracture, such as comorbidities, to improve the long-term outcome. The increased risk of further fractures adding to morbidity and mortality is another important considertion, and standardized secondary prevention programs should reduce this risk. Nevertheless, by providing a comprehensive account of excess mortality, this study underlines the need for improved care for patients with hip fracture, both before surgery and after surgery, to reduce the risk of death.

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