Fracture types and risk factors in men with prostate cancer on androgen deprivation therapy: a matched cohort study of 19,079 men.
OBJECTIVE
Accumulating evidence shows that androgen deprivation therapy is associated with osteoporosis and fragility fractures of the spine, hip and wrist. One study suggested that androgen deprivation therapy may also be associated with nonfragility fractures in older men. Whether other clinical risk factors independently increase the risk of fractures is not certain.


METHODS
Using linked administrative databases in Ontario, Canada, we matched 19,079 men 66 years old or older with prostate cancer with at least 6 months of continuous androgen deprivation therapy or bilateral orchiectomy with men with prostate cancer who had never received androgen deprivation. Matching variables were age, prior cancer treatment, diagnosis year, comorbidity, medication, prior fractures and socioeconomic variables. Primary outcomes were a typical fragility fracture of the spine, hip or wrist and any fracture. Independent predictors of fracture outcomes were assessed with Cox proportional hazards models.


RESULTS
At a mean 6.47-year followup androgen deprivation therapy was associated with an increased risk of fragility fracture (HR 1.65, 95% CI 1.53-1.78) and any fracture (HR 1.46, 95% CI 1.39-1.54). Independent predictors of fragility and any fracture were increasing age, prior bone thinning medications, chronic kidney disease, prior dementia, prior fragility fracture and prior osteoporosis diagnosis or treatment (p <0.05).


CONCLUSIONS
Continuous androgen deprivation therapy for at least 6 months is associated with an increased risk of fracture. Increasing age, prior osteoporotic fracture and dementia are important clinical factors that may warrant greater consideration of anti-osteoporotic therapy in these men.
Alibhai
Shabbir M H
SM
Division of General Internal Medicine and Clinical Epidemiology and Osteoporosis Program, University Health Network, Toronto, Ontario, Canada. shabbir.alibhai@uhn.on.ca
Duong-Hua
Minh
M
Cheung
Angela M
AM
Sutradhar
Rinku
R
Warde
Padraig
P
Fleshner
Neil E
NE
Paszat
Lawrence
L
D000368:Aged; D000726:Androgen Antagonists / Q000009:adverse effects*; D015331:Cohort Studies; D050723:Fractures, Bone / Q000145:classification* / Q000453:epidemiology* / Q000209:etiology; D006801:Humans; D008297:Male; D009919:Orchiectomy; D057216:Propensity Score; D011471:Prostatic Neoplasms / Q000188:drug therapy*; D012307:Risk Factors
D000726:Androgen Antagonists