Despite guidelines recommending the use of bisphosphonates for men on androgen deprivation therapy (ADT), prescription rates remain low, even among patients at high risk for fractures, according to a research letter published in JAMA.
“Androgen deprivation therapy (ADT) is an effective, widely used therapy for men with prostate cancer. Adverse effects include bone loss and increased fracture risk. Canadian guidelines recommend bisphosphonate use in men with osteoporosis or fragility fracture as early as 2002 and in men on ADT in 2006,” the researchers wrote.
To learn more about bisphosphonate prescribing patterns in this patient population, Husayn Gulamhusein, BHSc, of the University Health Network in Toronto, and colleagues evaluated rates of bisphosphonate prescriptions in men starting ADT in Ontario from 1995 to 2012 using administrative databases at the Institute for Clinical Evaluative Services and the Ontario Cancer Registry.
The researchers were able to capture any bisphosphonate claim within 12 months of ADT initiation via the database. They then evaluated prescriptions for three groups: all nonusers of bisphosphonates, patients with prior osteoporosis and patients with prior fragility fracture.
The researchers identified 35,487 men with prostate cancer who initiated ADT during the study. Among nonusers, bisphosphonate claims increased from 0.35 per 100 persons (95% CI, 0.17-0.53) during 1995 to 1997 to 3.40 per 100 persons (95% CI, 2.88-3.92) during 2010 to 2012 (P<.001). Rates also remained low among patients with osteoporosis or prior fragility fracture, according to the data.
Results revealed a peak in bisphosphonate claims among all three groups during 2007 to 2009, reaching a high of 11.89 per 100 persons (95% CI, 7.23-16.55) in patients with prior osteoporosis.
Men aged at least 66 years starting ADT for prostate cancer and who had undergone surgical removal of one or both testicles or received at least 6 months of continuous medical ADT and survived at least 1 year after initiation of therapy were included in the study.
“As the most widely used class of prescription drugs for osteoporosis, this suggests limited awareness among clinicians regarding optimal bone health management,” the researchers wrote.
They noted, however, that negative media attention regarding a link between bisphosphonates and rare osteonecrosis of the jaw and atypical femoral fractures may be partially responsible for the decrease in bisphosphonate prescriptions after 2009.
“This is appropriate for groups at low risk for fractures, but the decrease in use for high-risk patients is concerning,” the researchers wrote.
“Although the optimal rate of bisphosphonate use in men on ADT is unknown, it is reasonable that most men with prior osteoporosis or fracture should be taking a bisphosphonate or other effective bone medication.”