(B-122) Real-World Trends in Prenatal Antirheumatic Drug Utilization in Ontario, Canada: A Cross-Sectional Time Series Analysis

Background: Pregnant individuals living with rheumatic diseases, including rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), psoriatic arthritis (PsA), and ankylosing spondylitis (AS), are at a higher risk for adverse pregnancy outcomes due to significantly increased systemic inflammation. Therefore, many continue disease-modifying antirheumatic drug (DMARD) therapy to control maternal disease activity.

Objectives: To describe real-world trends in prenatal DMARD use among pregnant individuals with rheumatic conditions by leveraging routinely collected population-based healthcare administrative claims data.

Methods: We conducted a repeated cross-sectional time-series analysis using claims data at ICES in Ontario, Canada and reported annual utilization patterns of conventional synthetic and biological DMARDs among pregnant individuals with RA, SLE, PsA, or AS who delivered a liveborn or stillborn singleton infant between April 1, 2006, and March 31, 2021. We also characterized the beneficiary population for calendar years 2007, 2011, 2015, and 2019, covering demographic information, healthcare utilization, and DMARD utilization.

Results: The study cohort included a total of 6,732 pregnant individuals with rheumatic conditions. Over our study period, prenatal DMARD use among ODB beneficiaries significantly increased 6% from 53.6 beneficiaries per 100 eligible population in fiscal year 2006 to 56.9 beneficiaries per 100 eligible population in fiscal year 2020 (p = .04). While conventional synthetic DMARD use remained relatively stable, the rate of biological DMARD use increased 292% from 7.1 beneficiaries per 100 eligible population in fiscal year 2006 to 27.8 beneficiaries per 100 eligible population in fiscal year 2020 (p = .01). Across our annual cohorts from 2007, 2011, 2015, and 2019, DMARD use overall increased from 22.9% in 2007 to 26.0% in 2019 (p < .001). The proportion of DMARD users receiving only one drug increased from 18.8% in 2007 to 20.0% in 2019, while the proportion of those receiving two or more drugs also increased from 4.2% in 2007 to 6.0% in 2019 (p < .001). Further, the proportion of conventional synthetic DMARD users increased from 14.6% in 2007 to 14.7% in 2019 (p = .001), while the proportion of biological DMARD users increased from 8.3% in 2007 to 12.7% in 2019 (p < .001). Lastly, the proportion of individuals continuously using biological DMARDs throughout pregnancy increased from 13.8% in 2007 to 21.8% in 2019 (p = .04).

Conclusions: DMARD use during pregnancy has risen, with biological DMARDs increasingly being used in frequency and duration to control maternal disease activity throughout pregnancy. Future studies should consider how prenatal DMARD use trends correlate with pregnancy outcomes in this patient population.