Simplified 10-Year Absolute Fracture Risk Assessment: A Comparison of Men and Women

Abstract 

A simplified (semiquantitative) approach developed by the Canadian Association of Radiologists and Osteoporosis Canada (denoted as CAROC) for absolute fracture risk assessment incorporates age, sex, prior fragility fracture, and systemic corticosteroid use, together with bone mineral density (BMD) to define absolute fracture risk. The CAROC system has been shown to predict fracture rates in women referred for clinical BMD testing, but it is uncertain how this system performs in routine clinical practice in men who are much less likely to undergo BMD testing with potential for referral biases. Thirty-six thousand seven hundred and thirty women and 2873 men aged 50yr or older at the time of baseline BMD testing were identified in a database containing all clinical dual-energy X-ray absorptiometry test results for the Province of Manitoba, Canada. Population-based health service records from 1987 to 2008 were assessed for fracture codes and medication use. Fracture risk under the CAROC model was categorized as low (<10%), moderate (10–20%), or high (>20%). Ten-year fracture risk estimated by the Kaplan-Meier method showed the same gradient in observed fracture risk for men and women. Despite evidence of greater referral bias in men resulting in a higher rate of clinical risk factors, the performance of the prediction algorithm was not affected.

Key Words: Absolute risk, administrative data, bone mineral density, dual-energy X-ray absorptiometry, fractures, historical cohort study, men, osteoporosis