38 Background: Androgen deprivation therapy (ADT) is a cornerstone of advanced prostate cancer (PCa) treatment, however several side-effects are associated with its long-term use. Notably, loss of bone mineral density (BMD) is accelerated which increases fracture risk. Guidelines recommend BMD testing when initiating ADT to properly assess baseline fracture risk. The objective was to examine the proportion of BMD testing in men initiating long-term ADT in Quebec. Methods: The cohort consists of men extracted from Quebec public healthcare insurance administrative databases who were diagnosed with PCa from 2001-2012 and treated by ADT for at least one continuous year. The primary study outcome was the receipt of baseline BMD testing (defined as a BMD test identified in the period from 6 months prior to and up to 12 months after ADT initiation). Multivariable generalized linear mixed with a logit link was performed to identify variables associated with baseline BMD testing accounting for physician clustering. Results: We identified 7,069 patients, of which 887 (12.6%) underwent baseline BMD testing. Baseline BMD testing varied by year of ADT initiation, from 7.7% in 2001-2003 to 12.3% in 2013-2012. Following multivariable analyses, later years of ADT initiation (2004-2006, 2007-2009, 2010-2012, 2013-2015) remained associated with higher odds of baseline BMD testing compared to the earlier years (2001-2003) (ORs ranging from 1.43-1.88; p < 0.001). Conversely, age > 80 (OR 0.73; 95% CI 0.57-0.94; p = 0.001), greater Charlson comorbidity score (OR 0.51; 95%CI 0.34-0.75; p = 0.001), and rural residence (OR 0.60; 95%CI 0.48-0.75; p < 0.001) were associated with lower odds of baseline BMD testing. Conclusions: In our study population, rates of baseline BMD testing in men initiating ADT are low, although the rates increased over the course of the study period. Potential gaps identified in baseline BMD testing include older, more comorbid patients, and rural residence. Additional efforts emphasizing the importance of BMD testing in PCa guidelines may be needed.
199 The Clinical Significance of Bone Mineral Density Changes Following Long Term Androgen Deprivation Therapy in Prostate Cancer Patients Enrolled in the PCS V Trial
