FRAX sem inclusão da densidade mineral óssea: sua capacidade de identificar pacientes osteoporóticos e sua relação com valores médios de T-SCORE

Abstract

OBJECTIVES: The study sought to analyze the FRAX values calculated without the inclusion of bone mineral density (BMD)using the new FRAX tool available for the Brazilian population and their association toBMD values found through densitometry (DXA), and to determine the agreement between the FRAX designation of high risk for fracture and the diagnosis of osteoporosis using T- score according to theWorld Health Organization (WHO) criteria. METHODS:Questionnaires were administered to 339 patients referred for treatment of osteoporosis in a public service in 2010. Personal information, history of risk factors used in the calculation of FRAX and BMD values prior to treatment were collected. FRAX was calculated without the inclusion of BMD value using the instrument available at http://www.shef.ac.uk/FRAX for Brazil. Statistical analysis was performed using SPSS 13.0 software. The unpaired t test was used to compare T-score values between groups and chi-square test to compare qualitative variables. RESULTS:303 patients (89%) had osteoporosis according tothe WHO classification, however, only 114 patients (34%) had ahigh risk value of FRAX without BMD for fracture probability of the femoral neck in 10 years. When patients with high risk (≥3%) were compared to those with low risk (<3%) for hip fracture using FRAX without inclusion of BMD, there was statistical difference of T-score values in all bone sites studied. When this fixed threshold was chosen, the high-risk group had a mean T- score 0.65 SD lower than the low-risk group, when analyzed values of the femoral neck, 0.58 SD for total femur and 0.28 DP lumbar spine. CONCLUSIONS:The FRAX without BMD identified as high risk a low number of patients with osteoporosis. Despite this finding, we found good association between FRAX and T-score values, with selection of patients with a mean T-score 0.65SD lower in the femoral neck when considered the high risk group compared to low risk for hip fracture. There was a greater association between FRAX values and BMD in the femoral neck than in other bone sites.