Bone Marker Test May Indicate Adherence to Osteoporosis Drugs

Bone turnover markers could be used as a novel method to identify postmenopausal patients with osteoporosis who are not adherent to treatment with oral bisphosphonates, according to a new study published by Osteoporosis International.

Bone turnover markers can show early effects of the drug on bone tissue, and low response may indicate that the patient is not adherent to treatment, or there may be an underlying cause for the lack of response.

Oral bisphosphonates are commonly used to treat osteoporosis, but a large portion of patients discontinue or do not follow the treatment regimen within 1 year of initiation, according to the study. Identifying these patients early through use of a bone marker test could reduce the likelihood of a patient experiencing adverse events, such as a fracture.

The researchers who created the recommendations are part of the International Osteoporosis Foundation (IOF) and European Calcified Tissue Society (ECTS) Working Group.

The investigators used findings from the TRIO study to shape their their recommendations. The researchers suggest that physicians measure serum procollagen type 1 N-terminal propeptide (PINP) and collagen type 1 C-terminal telopeptide (CTX) initially and after 3 months of treatment to determine adherence.

The 3-month time period was recommended because the first few weeks of treatment is when a majority of patients do not adhere, according to the study.

"The use of bone turnover marker measurement to detect a lack of response to oral bisphosphonates is a practical and low-cost screening procedure which helps identify potential non-adherence in patients very early after treatment initiation,” said Adolfo Diez-Perez, MD, PhD, co-chair of the Joint IOF-ECTS Adherence Working Group. “The patients benefit as this opens up opportunity for discussion and early intervention with noncompliant patients, or can indicate that secondary causes of osteoporosis need to be assessed."

The researchers recommend that physicians treating patients whose PINP and CTZ bone turnover markers do not surpass the least significant change, which is 38% and 56%, respectively, evaluate treatment adherence, or work to determine the underlying cause of the osteoporosis.

Early identification of patients who are not adherent to oral bisphosphonate can significantly reduce costs if physicians are able to get them to adhere to the drugs. Adherence can prevent avoidable hospitalizations resulting from fractures. These hospitalizations present a cost burden to the healthcare system, and result in poor health outcomes for patients.

By implementing bone marker tests, physicians will be able to work through adherence issues with patients and improve outcomes, according to the authors.

“It will be interesting to further evaluate if these recommendations have an impact on adherence in a real-life setting,” concluded Richard Eastell, MD, co-chair of the Working Group.