e16517 Background: There are currently no published data on the patient experience with pain and pain medication use among the locally advanced or metastatic urothelial carcinoma (la/mUC) population. In this study, we quantified opioid use, as a proxy for pain, in patients with la/mUC and in matched non-cancer controls, using real-world data. Methods: We performed a retrospective claims analysis of adults diagnosed with UC who initiated ≥1 la/mUC therapy between 5/2016-6/2019 using the IBM MarketScan databases. Non-cancer controls were identified in 2 steps: 1) exact match on age/gender at index, 2) nearest neighbor propensity score matching (1:3 ratio) based on age, gender, region, insurance type, index year, enrollment time, and major comorbidities. Index was the date of first la/mUC therapy; index for controls was aligned to claims activity for matched patients with la/mUC. Baseline was the 6 months pre-index; follow-up was from index until disenrollment, death or study end (12/2019). Analyses examined the proportion of opioid users, number of opioid prescriptions, and daily morphine equivalent dose (MEQ). Results: A total of 1,293 patients with la/mUC and 3862 controls were included; mean (standard deviation [SD]) age at index was 64.1 (11.9) years for the la/mUC cohort and 64.8 (12.0) for controls, and most were male (60.2% and 61.3%, respectively). Mean (SD) follow-up was 15.1 (8.9) and 15.5 (8.6) months, respectively. A higher proportion of patients with la/mUC used opioids than controls during both baseline and follow-up (Table). Among opioid users, trends in opioid use were similar between the cohorts during baseline, with differences during follow-up (Table). At baseline, 63.6% (n=822) of patients with la/mUC had ≥1 opioid prescription which decreased during first-line (1L) treatment to 38.8% (n=502) and subsequently increased to 47.0% (n=159 of 338) during second-line (2L) treatment. The mean (SD) number of opioid prescriptions also increased during later therapy lines (1L: 0.92 [0.99], 2L: 1.37 [1.24]) along with increases in mean (SD) daily MEQ (1L: 69.8 [274], 2L: 133 [586]). Conclusions: This study underscores the impact of pain among patients with la/mUC, which is common at diagnosis, higher than matched controls, and worsens as the patient progresses. Improved disease control with more effective therapies may reduce pain in this population. [Table: see text]