476 The Fraxtm Tool In Spanish Women. Observed Fracture Incidence Over Ten Years Versus Predicted Fracture Probabilities In The Fridex Cohort

Azagra R, Ortiz S, Encabo G, Zwart M, Aguyé A, Roca G, Güell S, Iglesias M, Rosàs M, Bou V
Introduction and aim: FRAXTM tool has been validated in several cohorts, from various countries but not in Spain where the tool is being developed. The aim of the study was to compare the predicted probabilities and the observed fracture (Fx) incidence in female Spanish population after a 10 years follow-up period.
Material and methods: 771 untreated women aged > 40 yrs. from a multicentre cohort (FRIDEX) and without receiving any bone active drugs were included. All patients had a baseline questionnaire on osteoporosis risk factors, anthropometrics measurements and DXA-scan. Furthermore, a telephone interview collecting incidental fractures and risk factors after 10 years.
Results: We did not find significant differences in weight, height, smoking, alcohol intake, parental hip fracture or falls in the previous years between fractured (n=78) and not fractured (n = 693) patients. However, we found differences in age (61.3 vs 56.3 yrs.) p>0.001, previous fractures (39.7 vs 18.5%) p>0.001, rheumatoid arthritis prevalence (3.8 vs 0.7%) p=0.038 and osteoporosis in femoral neck (FN) at baseline (25.6 vs 7.6%) p>0.001 between fractured and not fractured. The women with hip, forearm, shoulder or clinical vertebral fracture, standardized per 100,000 people and year, were 220, 272, 298 and 230 respectively, that were similar results to those of other cohorts in Spain or France. For Major Fx the AUC ROC curve for FRAX without and with BMD was 0.683 (95% CI 0.619-0.748) and 0.696 (0.631-0.762) respectively. For Hip Fx the AUC was 0.886 (0.823-0.949) and 0.850 (0.738-0.963) respectively. The Hosmer- Lemeshow regression test showed a good relationship between the different quintiles of risk, but clearly tilted to the observed fractures. Overall FRAX expected to find only a 42% of the observed fractures.
Conclusions: FRAXTM underestimates the rate of incident fragility Fx over 10 years in a Spanish cohort. However, the AUC ROC curve shows a good probability for Hip Fracture.
The FRAXtm tool in Spanish women. Observed fracture incidence over ten years versus predicted fracture probabilities in the FRIDEX cohort