Bisophosphonate Use Questioned in Patients Undergoing Androgen Deprivation Therapy

Many male patients being treated for prostate cancer undergo androgen deprivation therapy (ADT), which has been shown to have several risky side effects, including osteoporosis. A recent study looked at whether adding bisphosphonate was helpful in countering these effects.

According to a study published in the Journal of the American Medical Association, patients undergoing ADT are at risk of developing “bone loss and increased fracture risk.” With this in mind, the authors also considered guidelines from Canada which call for bisphosphonate for osteoporosis patients or those with “fragility fractures,” particularly of the wrist, hip, or spine. The recommendation was added to those undergoing ADT in 2006.

“Rates of bone mineral density testing in men starting ADT were previously examined; however, bisphosphonate prescribing patterns are relatively unknown and have likely changed over time because of increasing awareness of bone effects of ADT and evidence of bisphosphonate efficacy,” the authors noted.

As part of their research the authors looked at the rates of patients in Ontario, Canada who started ADT between 1995 and 2012. Patient qualification for the study group included those who were at least 66-years-old who had one or both testicles removed or received at least 6 months of continuous ADT and survived at least one year of after ADT.

After some exclusions the patient pool totaled 35,487 men who met all the qualifications. During the time of the study the claims of bisphosphonate increased from 0.35 (95% CI, 0.17-0.53) per 100 people in the range of 1995-1997, to 3.45 (95% CI, 2.88-3.92 per 100 persons in 2010-2012 (P<.001). “Even among those with osteoporosis or fragility fracture, rates remained low,” the authors added.

The total patient pool was divided into three groups: nonusers of bisphosphonates, patients with prior osteoporosis, and those with fragility fracture. The authors noted use of the prescription was not particularly high among any of the groups. The high, they noted was in 2007-2009 of 11.89 (95% CI, 7.23-16.55) per 100 persons with prior osteoporosis.”

“Our results show that bisphosphonate prescriptions among men receiving ADT remained low during the study period, even for those at high risk of subsequent fractures,” the authors said. “As the most widely used class of prescription drugs for osteoporosis, this suggests limited awareness among clinicians regarding optimal bone health management.”

Data from the study also showed a decrease in usage of the drug after 2009. They attributed this in part to, “recent negative media regarding the association of bisphosphonates with rare osteonecrosis of the jaw and atypical femoral fractures.” The concerns, they said, were “appropriate for groups at low risk for fractures, but the decrease in use for high-risk patients is concerning.”