POS0943 GEOGRAPHIC VARIATION OF ANKYLOSING SPONDYLITIS (AS) DIAGNOSIS AND TREATMENT IN THE UNITED STATES: A REAL-WORLD EVIDENCE STUDY
Authors: Deodhar A. , Kruzikas D. , Zhou L. , Biljan A. , Saffore C. 
Published: May 2021

Background:AS is a chronic inflammatory immune-mediated disease primarily affecting the sacroiliac joints and spine, with a prevalence of 0.2%–0.5% in the United States.1 Because radiographic features of the disease can take years to develop, diagnosis may be delayed by up to 10 years2, which can negatively affect patients’ function, ability to work, and overall quality of life.Objectives:To describe geographic variations in AS diagnostic prevalence and treatment in the United States.Methods:This study utilized the IBM® MarketScan® Administrative Claims Database from 2014–2019. Patients (pts) ≥18 years of age with AS, continuous medical and pharmacy enrollment during the calendar year, and complete geographic information during the study period were included. Pts were identified by having ≥1 claim with ICD-9-CM or ICD-10-CM codes for AS (720.0 or M45.x, respectively). Two AS diagnosis definitions were used; Definition 1 (D1): Pts with ≥1 claim for an AS diagnosis in the year by any provider and Definition 2 (D2): Pts with ≥2 claims for an AS diagnosis within 18 months by rheumatologists. Annual AS diagnostic prevalence rates were calculated for both groups; treatment was evaluated among pts with D2. Diagnosis and treatment rates were assessed from 2014–2019 at the national and state levels and reported for states where >20 pts received an AS diagnosis (D1 or D2) or respective treatment (D2). The effect of age, sex, race (surrogate for HLA-B27), and rheumatologist per capita on geographic variation was assessed.Results:The number of pts included per year ranged between 10,811–13,077 (D1) and 3,775–4,901 (D2). AS diagnostic prevalence increased over time for both groups, with the annual prevalence rate per 10,000 persons for D2 pts increasing from 2.5 in 2014 to 3.5 in 2019 (Table 1). The AS diagnostic prevalence by D2 in 2019 was highest for Idaho (13) and Colorado (6), and lowest for Michigan (2). The state variations in prevalence did not appear to be explained by age, sex, racial distribution, or rheumatologists per capita. The percentage of D2 pts receiving advanced therapies (all FDA-approved indicated biologic disease-modifying antirheumatic drugs [bDMARDs] for AS) were >70% and increased each year, whereas the use of conventional synthetic DMARDs (csDMARDs) decreased (Figure 1. next page). While opioid use decreased, 37% of D2 pts were prescribed such treatment in 2019. Percentage of D2 pts receiving advanced therapy in 2019 was highest (91) in Minnesota and South Carolina and lowest in Idaho (69) and Indiana (70). In 2019, the percentage of D2 pts using csDMARDs in 2019 was highest in Oklahoma (33) and lowest (16) in North Carolina and New York, while for opioids it was highest in Idaho (69) and lowest in Wisconsin (28).Conclusion:The prevalence of AS is increasing each year nationally, with significant variability observed across states that is not explained by differences in age, sex, race, or rheumatologists per capita. Among pts with confirmed AS diagnosis (D2), national rates of csDMARDs and opioids are decreasing although opioid use is still high, and high treatment rates exist for advanced therapies. Rates of all treatments also vary substantially across states. Observed variations may indicate the opportunity for further education that can be targeted based on regional need to improve diagnosis and treatment.References:[1]Reveille JD. Am J Med Sci. 2011. 2. Deodhar A, et al. Arthritis Rheumatol. 2016.Table 1.AS diagnostic prevalence by calendar year, 2014–2019Patients with ≥1 AS diagnosis (D1)Patients with ≥2 AS diagnoses by rheumatologists (D2)YearNumber of annual enrolleesNumber of patients with ASPrevalence rate/10,000Number of patients with ASPrevalence rate/10,000201419,470,78013,0776.74,9012.5201515,159,11811,8637.84,2782.8201614,836,59412,8018.64,4733.0201712,618,30110,8118.63,7753.0201813,460,22412,2599.14,3023.2201912,105,04911,6469.64,2943.5Acknowledgements:Medical writing services provided by Alan Saltzman of Fishawack Facilitate Ltd, part of Fishawack Health, and funded by AbbVie.The design, study conduct, and financial support for the study were provided by AbbVie. AbbVie participated in the interpretation of data, review, and approval of the abstract. No honoraria or payments were made for authorship.Disclosure of Interests:Atul Deodhar Speakers bureau: Novartis, Pfizer, Consultant of: Novartis, Pfizer, AbbVie, Eli Lilly, UCB Pharma, GlaxoSmithKline, Galapagos, Janssen, Boehringer Ingelheim, Celgene, Amgen, Grant/research support from: Novartis, Pfizer, AbbVie, Eli Lilly, UCB Pharma, GlaxoSmithKline, Denise Kruzikas Shareholder of: AbbVie, Employee of: AbbVie, Lili Zhou Employee of: AbbVie, Ana Biljan Shareholder of: AbbVie, Employee of: AbbVie, Christopher Saffore Shareholder of: AbbVie, Employee of: AbbVieFigure 1.