Clinical Studies
Fall Direction, Bone Mineral Density, and Function: Risk Factors for Hip Fracture in Frail Nursing Home Elderly

https://doi.org/10.1016/S0002-9343(98)00115-6Get rights and content

Abstract

Purpose: To determine the importance of fall characteristics, body habitus, function, and hip bone mineral density as independent risk factors for hip fracture in frail nursing home residents.

Subjects and Methods: In this prospective, case-control study of a single, long-term care facility, we enrolled 132 ambulatory residents (95 women and 37 men) aged 65 and older, including 32 cases (fallers with hip fracture) and 100 controls (fallers with no hip fracture). Principal risk factors included fall characteristics, body habitus, measures of functional assessment, and hip bone mineral density by dual-energy X-ray absorptiometry.

Results: In multivariate analysis, including only those with knowledge of the fall direction (n = 100), those who fell and suffered a hip fracture were more likely to have fallen sideways (odds ratio 5.7, 95% confidence interval [CI] 1.7 to 18, P = 0.004) and have a low hip bone mineral density (odds ratio 1.9, 95% CI 0.97 to 3.7, P = 0.06) than those who fell and did not fracture. When all participants were included (n = 132) and subjects who did not know fall direction were coded as not having fallen to the side, a fall to the side (odds ratio 3.9, 95% CI 1.3 to 11, P = 0.01), low hip bone density (odds ratio 1.8, 95% CI 1.03 to 3, P = 0.04), and impaired mobility (odds ratios 6.4, 95% CI 1.9 to 21, P = 0.002) were independently associated with hip fracture. Sixty-seven percent of subjects (87% with and 62% without hip fracture) had a total hip bone mineral density greater than 2.5 SD below adult peak bone mass and were therefore classified as having osteoporosis using World Health Organization criteria.

Conclusions: Among frail elderly nursing home fallers, the preponderance of whom are osteoporotic, a fall to the side, a low hip bone density, and impairment in mobility are all important and independent risk factors for hip fracture. These data suggest that, among the frailest elderly, measures to reduce the severity of a sideways fall and improve mobility touch on new domains of risk, independent of bone mineral density, that need to be targeted for hip fracture prevention in this high-risk group.

Section snippets

Study design

Ambulatory subjects who fell and fractured a hip (case patients) were compared with ambulatory fallers who did not (control subjects). A fall was defined as a sudden, unexpected descent from a standing, sitting, or horizontal position, without loss of consciousness. Ambulatory was defined as the ability to walk, regardless of whether an assistive device (ie, cane or walker) was used.

Subjects

Cases and controls were all 65 years of age and over, had suffered a fall, and were stable enough to undergo bone

Results

Of the 272 residents at Hebrew Rehabilitation Center for Aged who were eligible for the study, 49% (n = 132) agreed to participate. There were no significant differences between participants and nonparticipants in terms of proportion of patients with hip fracture, gender, age, weight, height, or body mass index (Table 1). Fall characteristics and most measures of functional assessment (mobility, dressing, toileting) or mental status were also similar (Table 1). Dining was the only functional

Discussion

Our primary objective was to determine whether four separate domains of risk—fall characteristics, body habitus, functional assessments, and bone mineral density—were risk factors for hip fracture in elderly nursing home residents. The data suggest that in such patients, a fall to the side, low hip bone density, and functional impairment in mobility are important and independent risk factors for hip fracture. Moreover, each assesses a unique domain of risk and is associated with different

Acknowledgements

We are indebted to the nursing staff of the Harvard-Thorndike General Clinical Research Center at the Beth Israel Deaconess Medical Center; to Lauri Maitland-Ramsey, MPH, Meryl Poku, and Clorinda Cali, for assistance with recruitment and bone density imaging; and to Dawn Griffiths for excellent assistance with preparation of the manuscript.

References (44)

  • C.I Gryfe et al.

    A longitudinal study of falls in an elderly populationI. Incidence and morbidity

    Age Ageing

    (1977)
  • M.C Nevitt et al.

    Risk factors for recurrent nonsyncopal fallsA prospective study

    JAMA

    (1989)
  • W.A Ray et al.

    Psychotropic drug use and the risk of hip fracture

    NEJM

    (1987)
  • D.T Felson et al.

    Impaired vision and hip fractureThe Framingham Study

    J Am Geriatr Soc

    (1989)
  • M.E Tinetti

    Factors associated with serious injury during falls by ambulatory nursing home residents

    J Am Geriatr Soc

    (1987)
  • S.L Greenspan et al.

    Fall severity and bone mineral density as risk factors for hip fracture in ambulatory elderly

    JAMA

    (1994)
  • U.A Liberman et al.

    Effect of treatment with oral alendronate on bone mineral density and fracture incidence in postmenopausal osteoporosis

    NEJM

    (1995)
  • M.C Chapuy et al.

    Vitamin D3 and calcium to prevent hip fractures in elderly women

    NEJM

    (1992)
  • W.C Hayes et al.

    Impact near the hip dominates fracture risk in elderly nursing home residents who fall

    Calcif Tissue Int

    (1993)
  • W.C Chumlea et al.

    Estimating stature from knee height for persons 60 to 90 years of age

    J Am Geriatr Soc

    (1985)
  • J.N Morris et al.

    Resident Assessment Instrument Training Manual and Resource Guide

    (1991)
  • C.C Gluer et al.

    Comparative assessment of dual-photon absorptiometry and dual-energy radiography

    Radiology

    (1990)
  • Cited by (289)

    View all citing articles on Scopus

    Supported by NIH Grants CA41295, P30-AG08812, and M01-RR01032 (Beth Israel Deaconess Medical Center, General Clinical Research Center); and the Maurice E. Mueller Professorship in Biomechanics, Harvard Medical School, Boston, Massachusetts (Dr. Hayes).

    View full text