Association between GnRH analogue use and atopic diseases in patients with prostate cancer: A population-based retrospective cohort study

PURPOSE: Gonadotropin-releasing hormone (GnRH) analogues reduce testosterone levels to castration levels in patients with prostate cancer. However, the role of testosterone in atopic diseases has remained undefined. We aimed to investigate this role. MATERIALS AND METHODS: This retrospective cohort study was conducted using the National Health Insurance Research Database (NHIRD). Patients with prostate cancer were categorized into two groups according to whether they received GnRH analogue treatment (study group I) or not (study group II), and men without prostate cancer and with no GnRH analogue use were defined to comprise the comparison group after their ages and index years were matched with group II. Cox proportional hazard models were used to assess the hazard ratio (HR) of atopic diseases. RESULTS: Group I, group II, and the comparison group comprised 663, 2,172, and 8,688 individuals, respectively. Group I had a significantly lower risk of atopic diseases (adjusted HR: 0.66, 95% CI, 0.49–0.89, p < 0.01) than did group II. A reduced risk of atopic diseases was found when GnRH analogues were prescribed for 2 months (adjusted HR 0.53, 95% CI, 0.29–0.97, p = 0.04) and 2–14 months (adjusted HR 0.66, 95% CI, 0.49–0.89, p = 0.007). No significant difference in the risk of atopic diseases between group II and the comparison group was observed. CONCLUSIONS: A decreased risk of atopic diseases was observed in patients with prostate cancer treated with GnRH analogues. Further studies are warranted to verify the association between testosterone levels and atopic diseases.