Assessment of Underdiagnosis of Tardive Dyskinesia by Geographic Region, Social Determinants, and Other Patient Characteristics

Introduction Tardive dyskinesia (TD) is a hyperkinetic movement disorder associated with antipsychotics (APs). Objective To estimate TD diagnosis rates across geographic regions of the United States (US) among adults who use APs. Methods In this retrospective cohort study, patients with ≥1 AP claim (≥30-day supply) followed by TD diagnosis (index date) aged ≥18 years at index date with ≥12 months of continuous insurance eligibility after index date and geographic location information were identified in the IBM MarketScan © commercial insurance database (2012– 2019). Additional information was collected from the US census, the Internal Revenue Service, and the Centers for Medicare & Medicaid Services. . Observed TD diagnosis rates were estimated by metropolitan statistical area (MSA; ie, a major city and surrounding geographic areas linked by socioeconomic factors with ≥50,000 individuals). A weighted multivariable linear regression model was used to calculate expected TD diagnosis rates per 1000 patients with an AP prescription at the MSA level. Estimated and expected TD diagnosis rates were aggregated at the state level. Underdiagnosis of TD was defined as the observed TD diagnosis rate being lower than the expected TD diagnosis rate. Results Among 572,314 people who met inclusion criteria, the mean observed TD diagnosis rate across 341 MSAs was 3.10 per 1000 patients with an AP prescription; 86 (25.2%) MSAs had no patients with a TD diagnosis. Over 50% of MSAs and states had an underdiagnosis of TD. MSAs with the highest expected TD diagnosis rates were Missoula, MT (5.47), Billings, MT (5.39), and Madison, WI (5.16). MSAs with the highest observed TD rates were Chambersburg-Waynesboro, PA (18.52), Napa, CA (13.70), and San Angelo, TX (13.07). MSAs with the largest negative differences between observed and expected TD diagnosis rates (ie, highest underdiagnosis rates) were Missoula, MT (−5.47), Billings, MT (−5.39), and Gainesville, FL (−4.39). States with the highest expected TD rates were Montana (5.28), Idaho (4.52), and Alaska (4.32). States with the highest observed TD rates were North Dakota (7.09), Idaho (5.85), and New Mexico (5.67). States with the highest underdiagnosis rates were South Dakota (−3.72), Vermont (−3.57), and Montana (−3.21). Conclusions Overall, this study showed that TD was underdiagnosed in >50% of US geographic regions. This research highlights opportunities for improved TD recognition in areas with TD underdiagnosis. Funding Teva Branded Pharmaceutical Products R&D, Inc.