Development and application of FRAX in the management of osteoporosis in Ireland

Abstract

The Irish Fracture Risk Assessment (FRAX) tool is the first fracture prediction model that has been calibrated using national hip fracture incidence data and Irish mortality rates. The Irish FRAX tool can be used to identify intervention thresholds for Ireland based on the fracture probability equivalent to that of a woman with a prior fracture. The objective of the study is to describe the 10-year probability of osteoporotic fracture in men and women in Ireland by using the Irish version of the FRAX tool and to develop FRAX-based intervention thresholds. The FRAX model for Ireland was constructed from the age- and sex-stratified hip fracture incidence rates from 2008 to 2010. For other major osteoporotic fractures, incidence rates were imputed, using age- and sex-specific Swedish ratios for hip to osteoporotic fracture risks. Lifetime fracture probabilities and 10-year probabilities of a major osteoporotic fracture were calculated in women to determine potential intervention thresholds. Based on the incidence of hip fracture and mortality, the average lifetime probability of hip fracture from the age of 50 years was 7.8% in men and 18.2% in women from Ireland. Probability-based intervention threshold derived from BMD T-scores were problematic. When a BMD T-score≤-2.5 standard deviations (SD) was used as an intervention threshold, the increase in risk associated with the BMD threshold decreased progressively with age such that, at the age of 80 years or more, a T-score of -2.5 SD was protective. The 10-year probability of a major osteoporotic fracture by age, equivalent to that of women with a previous fracture, rose with age, from 3.0% at the age of 40 years to 30% at the age of 90 years, and identified women at increased risk at all ages. The Irish FRAX tool is the first fracture prediction model that has been calibrated using national hip fracture incidence data and Irish mortality rates.