Even when taking oral bisphosphonates, a third of women with osteoporosis may have an elevated risk of fracture, according to results from a retrospective study published in Bone.
The researchers analyzed data from a cohort of women aged 50 years or older who had been adherent to oral bisphosphonates for at least 2 years, which were extracted from the database of a multi-system health information exchange. For the purpose of the study, adherence was defined as having a dispensed medication possession ratio â¥ 0.8.
The study included 7435 adherent women and data on dual-energy X-ray absorptiometry (DXA) scans, taken either before or after adherence to bisphosphonates, were available for 3110 of them. Incident fractures linked to osteoporosis were reported in 7% of the total cohort. The incidence was 6% in the 601 women who underwent DXA to evaluate bone mineral density (BMD) both before and after taking bisphosphonates. In that group, 22% had a post-treatment T-score â¤â â2.5 and 16% had a drop in BMD of at least 5%. Incident fracture was predicted by age, previous fracture, and a variety of co-morbidities, but not by race, glucocorticoid treatment, or type of bisphosphonate.
The investigators concluded that in spite of bisphosphonate adherence, 7% of the women had incident osteoporotic fractures and 25% had either fracture, decreased BMD, or persistent osteoporotic BMD. They urged further study to determine best achievable goals for osteoporosis therapy and which patients would benefit from different therapies.