Performance of the Brazilian Fracture Assessment Risk Tool (FRAX) model and the age-dependent intervention thresholds according to National Osteoporosis Guideline Group (NOGG) guidelines on fracture prediction in community-dwelling older adults: the São Paulo Ageing and Health (SPAH) Study.

The SPAH study is a population-based prospective cohort of Brazilian community-dwelling elderlies with higher fracture risk than observed in the studies used to construct the Brazilian FRAX model. In this study, the FRAX tool was a good fracture predictor within this high-risk elderly cohort, especially when calculated without bone density.

Purpose: To determine the performances of FRAX and age-dependent intervention thresholds according to National Osteoporosis Guideline Group (NOGG) guidelines with and without bone mineral density (BMD) regarding fracture prediction in community-dwelling elderly Brazilians.

Methods: Seven hundred and five older adults (447 women; 258 men) were followed for 4.3 ± 0.8 years. FRAX risk for hip and major osteoporotic fractures with and without BMD was calculated at baseline. The bivariate analysis investigated the associations between the absolute probability of fracture (FRAX), as well as the age-dependent intervention thresholds (NOGG), and the incidence of vertebral fracture (VF), non-vertebral fracture (NVF), and major osteoporotic fractures (MOF), segregated by sex. Age-adjusted Poisson's multiple regression and ROC curves were constructed to determine FRAX and NOGG's accuracies as fracture predictors.

Results: Fractures occurred in 22% of women and 15% of men. FRAX with and without BMD was higher in women with all types of fractures (p < 0.001). Only NOGG risk classification without BMD was associated with NVF (p = 0.047) and MOF (p = 0.024). FRAX was associated with NVF in the multiple regression, regardless of BMD. ROC curves of FRAX with and without BMD had AUCs of 0.74, 0.64, and 0.61 for NVF, VF, and MOF, respectively. The most accurate risk cutoffs for FRAX were 8% for MOF and 3% for hip fractures. No statistically significant associations were found in men.

Conclusion: FRAX predicted NVF more accurately than VF or MOF in elderlies, regardless of BMD. These results reiterate that FRAX may be used without BMD, even considering that Brazilian elderlies have known higher fracture risk.