Age and Ageing Advance Access published online on June 9, 2008
Age and Ageing, doi:10.1093/ageing/afn128
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Fracture risk assessment in frail older people using clinical risk factors
1 Institute of Bone and Joint Research, University of Sydney, St Leonards, NSW 2065, Australia
2 Department of Public Health and Community Medicine, University of Sydney, Sydney, NSW 2006, Australia
3 Rehabilitation Studies Unit, University of Sydney, Ryde, NSW 2112, Australia
4 Centre for Education and Research on Ageing, University of Sydney, Concord, NSW 2139, Australia
5 Prince of Wales Medical Research Institute, UNSW, Randwick, NSW 2031, Australia
6 Anzac Research Institute, University of Sydney, Concord Hospital, Concord, NSW 2139, Australia
Address correspondence to: Jian Sheng Chen. Tel: (+61) 2 9926 7328; Fax: (+61) 2 9906 1859. Email: jschen{at}med.usyd.edu.au
Background: this study aims to develop and evaluate a simple fracture risk index for use in frail older people.
Methods: clinical risk factors were assessed at baseline for 2,005 older people (473 males, 1,532 females; mean age 85.7 years, SD 7.1 years) living in aged-care facilities. Fractures were ascertained for 2 years from baseline. Cox regression model was used to identify significant risk factors for fracture. Hazard ratios (HRs) from the model were assigned as weights. The risk index was calculated by multiplying the weights of all risk factors.
Results: during a mean follow-up of 1.64 years, 401 fractures occurred in 338 participants. Significant independent clinical risk factors for fracture were institution type, balance, history of previous fracture, cognitive function, number of medications, weight and lower leg length (n = 1,813). The index was capable of identifying higher-risk individuals, with almost an 8-fold increase in the risk of fracture for residents from the lowest 15% to the highest 18% of the score. Among 1-year survivors, a high score (
15) indicated approximately a one-in-six chance of fracture, while a low score (<8) indicated only a one-in-forty chance of fracture within a year. The area under the receiver operating characteristic (ROC) curve was 0.69 (95% CI: 0.65–0.72) and 0.68 (95% CI: 0.65–0.71) for identifying someone who would have a fracture in 1 and 2 years respectively.
Conclusions: this risk index could identify individuals at higher fracture risk among institutionalised older people, and thus, could help to rationalise the provision of fracture prevention programs in this population.
Keywords: fracture, aged, risk assessment, risk factors, elderly
Received 8 August 2007; accepted in revised form 26 February 2008.