Bisphosphonate use low in men on androgen deprivation therapy despite guidelines

Bisphosphonate prescriptions remain low for men on androgen deprivation therapy (ADT), even for those at high risk of subsequent fractures, a study found.

Using administrative databases at the Institute for Clinical Evaluative Sciences and the Ontario Cancer Registry, researchers examined rates of bisphosphonate prescriptions in men 66 years of age or older starting ADT in Ontario between 1995 and 2012. The men had undergone surgical removal of 1 or both testicles or had received at least 6 months of continuous medical ADT and survived at least 1 year after starting ADT. Bisphosphonate use was analyzed in 3 groups: all nonusers of bisphosphonates, those with prior osteoporosis, and those with prior fragility fracture.

Results appeared in a research letter in the Dec. 3 Journal of the American Medical Association.

There were 35,487 men with prostate cancer who began ADT during the study period. Bisphosphonate claims among all nonusers increased from 0.35 (95% CI, 0.17 to 0.53) per 100 persons in 1995 to 1997 to 3.40 (95% CI, 2.88 to 3.92) per 100 persons in 2010 to 2012 (P<0.001). Even among those with prior osteoporosis or fragility fracture, rates remained low. Among all 3 groups, peak bisphosphonate claims occurred in 2007 to 2009, with a high of 11.89 (95% CI, 7.23 to 16.55) per 100 persons in those with prior osteoporosis.

Bisphosphonates are the most widely used class of prescription drugs for osteoporosis, and thus these findings suggest limited awareness among clinicians regarding optimal bone health management, the authors concluded. They noted that Canadian guidelines have recommended bisphosphonate use for men with osteoporosis or fragility fracture since 2002 and for men on ADT since 2006.

The researchers speculate that the decrease in bisphosphonate prescriptions after 2009 may be partly due to the association of bisphosphonates with rare occurrences of osteonecrosis of the jaw and with atypical femoral fractures. Still, they continued, while stopping the drug may be appropriate for groups at low risk for fractures, the decrease in use for high-risk patients is concerning.

“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,” they wrote.