Abstract Disclosure: T.J. Smith: Consulting Fee; Self; Amgen Inc, Viridian, Minghui, Lassen, Lundbeck. Other; Self; US patents covering the use of IGF-1 receptor inhibitors in TED which are held by UCLA and the Lundquist Institute. A. Meyers: Employee; Self; Amgen Inc. Stock Owner; Self; Amgen Inc. Q. Fu: Stock Owner; Self; Amgen Inc. Other; Self; Amgen Inc, former employee. R.J. Holt: Employee; Self; Amgen Inc. Stock Owner; Self; Amgen Inc. K. Zhu: Employee; Self; Amgen Inc. Stock Owner; Self; Amgen Inc. Background: Autoimmune thyroid conditions including Graves’ disease (GD) have been associated with hearing impairment.([1]-3) Approximately 90% of patients (pts) with thyroid eye disease (TED) have hyperthyroidism/GD. Teprotumumab, an insulin-like growth factor-I receptor inhibitor, significantly improves TED signs/symptoms and became the first FDA-approved treatment for TED in 2020. Hearing-related adverse events were identified in pivotal trials of teprotumumab in TED.4 This epidemiology study aims to describe the prevalence of hearing loss/ototoxicity via claims data in commercially insured pts with autoimmune thyroid conditions, TED, and those receiving teprotumumab, as well as the general population (gen pop). Methods: Five mutually exclusive cohorts were created using deidentified claims data (Merative MarketScan®): GD pts (index is first GD diagnosis [dx] code), TED pts (index is later of both GD dx or eye symptom codes within 1 yr), teprotumumab pts (index is first claim for teprotumumab), other Thyroid Disorders (TD) pts (index is TD dx), and gen pop pts. Pts with teprotumumab claim were excluded from other cohorts. Eligible pts were ≥18 years (yrs) of age, continuously enrolled for ≥6 months pre and post index, between 1/1/2020-12/21/2021. Demographics (age, sex) were described between the cohorts and the gen pop. Proportions of pts with inpatient and outpatient claims for hearing loss/ototoxicity claims and proportions with hearing loss/ototoxicity claims in the 3 yrs preceding index were calculated. Age-standardized prevalence was presented using gen pop as the reference. Results: Of 21,256,714 eligible pts, 82,629 GD, 4,455 TED, 2,758 teprotumumab, 1,261,250 TD and 4,857,408 gen pop pts were identified. 47% pts in the gen pop cohort were female vs 72.1-75.7% in the other cohorts. Gen pop cohort was younger (mean [SD] age: 53 [15.1] yrs) vs 58.0-61.5 [15.1-15.6] yrs in other cohorts. Age-standardized prevalence of hearing loss/ototoxicity claims on/after index date was 3.3% for GD, 5.2% for TED, 4.3% for teprotumumab, 3.9% for TD, and 3.9% for gen pop pts. Hearing loss/ototoxicity claims were prevalent in the 3 years prior to index among these patients: 30.8% GD, 36.6% TED, 35.4% teprotumumab, 31.5% TD, and 27.3%) gen pop pts had a hearing loss/ototoxicity claim. Conclusions: In this descriptive unadjusted analysis, we observed similar prevalence of hearing loss/ototoxicity claims across thyroid disorders, TED pts, teprotumumab pts, and the gen pop group. Between 27%-37% had claims prior to thyroid diagnosis or receiving teprotumumab. It is expected that future analyses could adjust the rates for potential confounders across cohorts.