(UroToday.com) Real-world data regarding treatment patterns for metastatic castration-resistant prostate cancer (mCRPC) remain scarce due to the lack of a specific ICD-10 code for these patients. Using the Optum Research Database, which includes enrollment information and medical/pharmacy claims for over 73 million enrollees with commercial coverage and 8.3 million enrollees with Medicare, the authors created a specific algorithm to identify patients with mCRPC with claims between 2008 and 2019. Criteria for identifying mCRPC patients included (1) more than one claim for prostate cancer, (2) one or more claims for pharmacologic or surgical castration, (3) metastatic disease, and (4) more than six months of continuous enrollment before and after the first metastatic disease claim. The authors then explored the association between clinically significant events (CSEs) and mCRPC treatment. CSEs were assessed during the first line of therapy that was used for mCRPC. To assess rates of clinically significant events (CSEs) on therapy, time on treatment was used as the denominator to control for different durations of treatment.