FRAX score with and without bone mineral density: a comparison and factors affecting the discordance in osteoporosis treatment in Thais

We investigate the rate of concordance between treatment recommendations of osteoporosis with 10-year probability of hip fracture calculated using FRAX scores with and without BMD. We found that predictions were concordant in 83.8% of patients. However, older age, lower BMD, and FRAX without BMD around the intervention threshold were associated with discordant results. In the discordant group, FRAX with BMD suggested treatment in more participants with lower age, higher BMI, and lower BMD when compared with FRAX without BMD. Introduction The Fracture Risk Assessment Tool (FRAX) is used to calculate the 10-year probability of fracture using important clinical factors, with bone mineral density (BMD) as an optional input variable. We aimed to determine the rate of concordance between treatment recommendations of osteoporosis with 10-year probability of hip fracture calculated using FRAX scores with and without BMD and to identify relevant clinical risk factors associated with discordance. Methods This was a cross-sectional study conducted in patients between 40 and 90 years of age who were screened for osteoporosis by BMD measurement using dual energy X-ray absorptiometry (DXA) from 2010 to 2018 at a university hospital in Thailand. A FRAX questionnaire was administered to determine demographic data and osteoporotic risk factors. FRAX scores with and without BMD were calculated for each participant using the Thai reference, and patients were categorized into either the treatment or non-treatment group based on a cut-off of 3% 10-year probability of hip fracture. When FRAX scores with and without BMD results were consistent, they were considered concordant. Otherwise, they were deemed discordant. Clinical risk factors were compared between the concordant and discordant groups. Results A total of 3545 participants were included in the study. The majority (83.8%) were in the concordant group. However, older age, lower BMD, and FRAX without BMD around the intervention threshold were significantly associated with discordant results. In the discordant group, FRAX with BMD suggested treatment in more participants with lower age, higher BMI, and lower BMD when compared with FRAX without BMD. Conclusion FRAX scores with and without BMD yielded concordant predictions regarding the 10-year probability of hip fracture suggesting pharmacological treatment. However, this concordance declined in elderly and osteoporotic participants and in those with FRAX without BMD around intervention threshold. BMD data may be required in these populations in order to facilitate accurate risk assessment.