Risk-Adjusted Mortality Rates of Elderly Veterans with Hip Fractures

https://doi.org/10.1016/j.annepidem.2006.12.004Get rights and content

Purpose

The goal of this research was to estimate 12-month survival rates for a large sample of elderly veterans after hip fracture with a risk-adjusted model and to compare the results of men to those of women.

Methods

The study design was a retrospective, secondary data analysis of national Veterans Health Administration (VHA) Medicare beneficiaries. The study population was 43,165 veterans with hip fracture first admitted to a Medicare-eligible facility during our specified enrollment period of 1999–2002. Measurement was a Cox proportional hazard model or survival analysis of hip fracture patients with an outcome of death over a 1 year period after discharge controlled by age, gender, and selected Elixhauser comorbidities.

Results

The unadjusted, 1 year mortality rates (30 days = 9.7%, 90 days = 17.5%, 180 days = 24%, 365 days = 32.2%) were slightly higher than the adjusted rates (30 days = 8.9%, 90 days = 15.6%, 180 days = 21.8%, 1 year = 29.9%). The mortality odds for women 12 months after hip fracture were 18%, compared with 32% for men. The comorbidity adjustment suggested that the presence of metastatic cancer increased the risk of death by almost 4 times compared with those patients without this diagnosis. Other particularly high-risk conditions included congestive heart failure, renal failure, liver disease, lymphoma, and weight loss, each of which increased the 1 year mortality risk by approximately two-fold.

Conclusions

One in 3 elderly male veterans who sustain a hip fracture dies within 1 year. Our work represents the first large study of hip fractures with a predominantly male sample and confirms that men have a higher mortality risk than women, as reported by previous researchers who used smaller samples that were mostly female. Fracture patients with metastatic cancer, renal failure, lymphoma, weight loss, and liver disease have higher mortality risks. The adverse outcomes associated with hip fracture argue for clinical intervention strategies, such as gait and balance testing, and osteoporosis diagnosis that may prevent fractures in both genders.

Introduction

Hip fractures (HFx) in the elderly are substantial sources of morbidity, mortality, and medical costs. Among all types of fall-related injuries, HFxs cause the greatest number of deaths, lead to severe health problems, and reduce quality of life 1, 2. Postfracture mortality is strongly and positively associated with prefracture functional impairment, cognitive impairment, older age, low physical activity, and chronic diseases 3, 4, 5, 6, 7, 8, 9, 10. One year after a HFx, most patients report some restrictions in ordinary living activities (11) and less than one third ever return to previous function levels 12, 13. A higher relative risk of dying is present in-hospital and persists months to years after the fracture 3, 4, 5, 6, 7, 14. While the incidence of HFx is greater among women 15, 16, 17, men who fracture experience higher morbidity and mortality 3, 4, 18, 19, 20. Past research has found that, regardless of the time horizon, men have a greater mortality risk after HFx compared with women 4, 13, 18, 21, but there is some dispute 22, 23; mortality rates for men vary widely from 16.5% to 37.5% 3, 7, 24. The gender difference in mortality rates has not been fully explained, but attributable factors for men may include older age at the time of fracture, increased morbidity, more postoperative complications, and lifestyle factors, such as smoking and alcohol use 3, 4, 5, 25. There is evidence 7, 21 that age and comorbidity burden alone do not eliminate the gender difference.

Although HFxs have been widely studied in women, more robust studies of HFx in men would be useful in resolving this issue. Most previous research into mortality after HFx has employed samples that are chiefly female or contain fewer than 1,000 patients, or both. The Veterans Health Administration (VHA) is the largest healthcare system in the United States with integrated patient data on elderly males, thus providing a large population to study. The goal of this research was to estimate 12-month survival rates for a large sample of elderly veterans post-HFx with a risk-adjusted model and to compare the results of men to those of women.

Section snippets

Data Source

This was a retrospective cohort analysis of veterans aged 65 years or older who sustained an HFx in the time period 1999–2002. The data source was Medicare; specifically, the Medicare Inpatient Standard Analytical File (SAF) and Denominator File for veterans supplied by the VA Information Resource Center (VIReC). VIReC identifies veterans for possible inclusion in their dataset if they are VHA eligible, enrolled in the VHA, use VHA care, or receive compensation from the Department of Veterans

Results

The descriptive statistics of the patient population are found in Table 1. During the study period (1999–2002), we identified 43,165 elderly veterans who were treated in Medicare facilities for their first HFx admission. Men constituted 87% of the study sample from a predominately Caucasian (94%) population. The average age of the sample was 80 years.

Table 2 presents the multivariate Cox proportional hazard estimates. Coefficients are expressed as the log-odds of the mortality rate and not the

Discussion

Elderly men who experience a HFx have a 1 in 3 chance of dying within 1 year after their initial admission date. Mortality risk for men is highest in the first months. The annual risk-adjusted rate and male hazard ratios are similar to those calculated by others 3, 4, 6, 24 and to the unadjusted rate given by Kamel (41) for veterans with HFx treated in the VHA. Our adjusted mortality rates are approximately 10% lower than the unadjusted rates across the 4 time intervals reported (30, 90, 180,

Conclusion

One in 3 elderly males who sustain an HFx dies within 12 months. Our work represents the first large study of HFxs incorporating males and confirms that men do have a higher mortality risk than women when adjusted for comorbidities, as reported by previous researchers who used smaller samples that were mainly female. Fracture patients with metastatic cancer, renal failure, and liver disease have particularly high mortality risk. The adverse outcomes associated with HFx argue for clinical

References (47)

  • J.J. Roche et al.

    Effect of comorbidities and postoperative complications on mortality after hip fracture in elderly people: prospective observational cohort study

    BMJ

    (2005)
  • I. Pande et al.

    Quality of life, morbidity, and mortality after low trauma hip fracture in men

    Ann Rheum Dis

    (2006)
  • H.X. Jiang et al.

    Development and initial validation of a risk score for predicting in-hospital and 1 year mortality in patients with hip fractures

    J Bone Miner Res

    (2005)
  • J. Alegre-Lopez et al.

    Factors associated with mortality and functional disability after hip fracture: an inception cohort study

    Osteoporos Int

    (2005)
  • L.E. Wehren et al.

    Hip fracture: risk factors and outcomes

    Curr Osteoporos Rep

    (2003)
  • H.E. Meyer et al.

    Factors associated with mortality after hip fracture

    Osteoporos Int

    (2000)
  • M. Cree et al.

    Mortality and institutionalization following hip fracture

    J Am Geriatr Soc

    (2000)
  • C. Cooper

    The crippling consequences of fractures and their impact on quality of life

    Am J Med

    (1997)
  • A. Ohlin et al.

    Unrecognized risks among veterans with hip fractures: opportunities for improvements

    J South Orthop Assoc

    (2003)
  • J.A. Stevens et al.

    Surveillance for injuries and violence among older adults

    MMWR Morb Mortal Wkly Rep

    (1999)
  • J.P. Empana et al.

    Effect of hip fracture on mortality in elderly women: the EPIDOS prospective study

    J Am Geriatr Soc

    (2004)
  • M. Fransen et al.

    Excess mortality or institutionalization after hip fracture: men are at greater risk than women

    J Am Geriatr Soc

    (2002)
  • J.A. Stevens et al.

    Reducing falls and resulting hip fractures among older women

    MMWR Morb Mortal Wkly Rep

    (2000)
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    This research was supported by the Department of Veterans Affairs, Veterans Health Administration, VISN-8 Patient Safety Center of Inquiry. The views expressed in this article are those of the authors and do not necessarily represent the views of the Department of Veterans Affairs.

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