Association between duration of gonadotrophin-releasing hormone agonist use and cardiovascular risks: A population-based competing-risk analysis

Background Although androgen deprivation therapy has known cardiovascular risks, it is unclear if its duration is related to cardiovascular risks. This study thus aimed to investigate the associations between gonadotrophin-releasing hormone (GnRH) agonist use duration and cardiovascular risks. Methods This retrospective cohort study included adult patients with prostate cancer receiving GnRH agonists in Hong Kong during 1999-2021. Patients who switched to GnRH antagonists, underwent bilateral orchidectomy, had <6 months of GnRH agonist, prior myocardial infarction (MI), or prior stroke was excluded. All patients were followed up until September 2021 for a composite endpoint of MI and stroke. Multivariable competing-risk regression using the Fine-Gray subdistribution model was used, with mortality from any cause as the competing event. Results In total, 4038 patients were analyzed (median age 74.9 years old, interquartile range (IQR) 68.7-80.8 years old). Over a median follow-up of 4.1 years (IQR 2.1-7.5 years), longer GnRH agonists use was associated with higher risk of the endpoint (sub-hazard ratio per year 1.04 [1.01-1.06], p = 0.001), with those using GnRH agonists for >= 2 years having an estimated 23% increase in the sub-hazard of the endpoint (sub-hazard ratio 1.23 [1.04-1.46], p = 0.017). Conclusion Longer GnRH agonist use may be associated with greater cardiovascular risks.