In the Journals

Bisphosphonate prescriptions low among men who underwent ADT

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January 2, 2015

Although guidelines recommend bisphosphonates for men who initiate androgen deprivation therapy, prescriptions for these agents in this patient population remain low, according to results of a study conducted in Canada.

Researchers observed the trend even among men at high risk for subsequent fractures.

The findings suggest “limited awareness among clinicians regarding optimal bone health management,” Husayn Gulamhusein, BHSc, of University Health Network in Toronto, and colleagues concluded.

ADT is a highly effective, frequently used treatment for men with prostate cancer. However, use is associated with adverse events such as bone loss and elevated risk for fractures.

Canadian guidelines recommend bisphosphonate use for men with osteoporosis or fragility fracture, as well as for men who undergo ADT.

Gulamhusein and colleagues used databases at the Institute for Clinical Evaluative Sciences and the Ontario Cancer Registry to assess rates of bisphosphonate prescriptions in men who initiated ADT in Ontario between 1995 and 2012.

The analysis included 35,487 men aged ≥66 years (median age, 75 years; range 71-80) who initiated ADT for prostate cancer. All men had undergone orchiectomy, or received at least 6 months of continuous ADT and survived at least 1 year after ADT initiation.

Bisphosphonate claims among all nonusers increased from 0.35 (95% CI, 0.17-0.53) per 100 persons in 1995-97 to 3.4 (95% CI, 2.88-3.92) per 100 persons in 2010-2012 (P<.01). Researchers reported peak use between 2007-2009.

Rates were low even among those with prior osteoporosis or fragility fracture. Among those with prior osteoporosis, bisphosphonate claims peaked in 2007-09 at 11.89 (95% CI, 7.23-16.55) per 100 persons.

The decrease in bisphosphonate prescriptions after 2009 may be due in part to published reports about the association between bisphosphonates and rare osteonecrosis of the jaw and atypical femoral fractures, researchers wrote.

“This is appropriate for groups at low risk for fractures, but the decrease in use for high-risk patients is concerning,” Gulamhusein and colleagues wrote.

Limitations of the study included lack of access to bone mineral density results that would allow a determination of the risk for future fracture; examination of prescription claims and not actual drug use; and an inability to generalize the findings to other geographic regions.

“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,” Gulamhusein and colleagues wrote.

Disclosure: The researchers report honoraria from Merck for continuing medical education events.