Androgen Deprivation Therapy and the Risk of Anemia in Men with Prostate Cancer

Background: The use of androgen deprivation therapy in prostate cancer may be associated with an increased risk of anemia, but the evidence remains limited. This study aimed to determine if androgen deprivation is associated with increased risk of anemia in patients newly diagnosed with prostate cancer. Methods: This was a population-based cohort study using the United Kingdom Clinical Practice Research Datalink linked to the Hospital Episode Statistics repository. The cohort consisted of 10,364 men newly diagnosed with nonmetastatic prostate cancer between 1 April 1998 and 30 September 2015. We used time-dependent Cox proportional hazards models to estimate adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for anemia (hemoglobin < 130 g/L) associated with current and past use of androgen deprivation therapy, compared with nonuse. Results: There were 3,651 incident anemia events during 31,574 person-years of follow-up (rate: 11.6/100 person-years). Current androgen deprivation therapy use was associated with a nearly three-fold increased hazard of anemia, compared with nonuse (23.5 vs. 5.9 per 100 person-years, respectively; HR: 2.90, 95% CI: 2.67, 3.16). The HR was elevated in the first 6 months of use (HR: 2.20, 95% CI: 1.95, 2.48) and continued to be elevated with longer durations of use. Past androgen deprivation therapy use was associated with a lower estimate (HR: 1.27, 95% CI: 1.12, 1.43), which returned closer to the null = 25 months after treatment discontinuation (HR: 0.95, 95% CI: 0.79, 1.15). Conclusions: The use of androgen deprivation therapy is associated with increased risk of anemia, which reverses upon treatment discontinuation.