POS0936 TUMOUR NECROSIS FACTOR INHIBITORS USE AND DISCONTINUATION AMONG PREGNANT WOMEN WITH CHRONIC INFLAMMATORY DISEASES

Background Previous guidelines (2006) recommended that tumour necrosis factor inhibitors (TNFi) be discontinued during pregnancy. Despite new (2016 & 2020) now recommending against this, the choice to stop TNFi pre-conception is patient- and provider-dependent. Observational studies have evaluated use of disease-modifying anti-rheumatic drugs (DMARDs) pregnancy, but few specifically assessed discontinuation pre-conception. Understanding trends predictors may help inform initiatives improve care optimize maternal fetal outcomes. Objectives We examined in over time, characteristics pregnant women with chronic inflammatory diseases who stopped using (without resuming pregnancy) compared those used at any time Methods created a cohort rheumatoid arthritis (RA), ankylosing spondylitis, psoriatic (PsA), psoriasis (PsO), and/or bowel (IBD) delivered between 2011 2019, MarketScan commercial database. was defined as least 1 filled prescription or infusion procedure claim, categorized according timing date relation gestational period: 1) only (i.e. claim 12 weeks preceding period none within period) 2) pregnancy period, including restarts, starts, continuing from pre-conception). Results identified 3,372 pregnancies; 13% before conception did not restart, 86% were exposed Pregnancies IBD patients accounted for 47% all pregnancies. Nearly pregnancies (95%). Compared IBD, more RA (difference 18%, 95% CI 15-21%) PsA/PsO (20%, 16-24%) their TNFi. Corticosteroid similar both exposure groups, while took likely non-biologic DMARDs concomitantly. Over lower proportion (2011-2013 19% vs 2014-2016 2017-2019 10%; p-value trend <0.0001). Conclusion In our sample, restart. The stopping decreased earlier years, possibly reflecting updated guidelines. Further research on years after 2020 ACR warranted. Table 1. Characteristics gestation (n=3,372). Total (n=3372) (n=470) (n=2902) Maternal Diagnosis, n (% ) 470/3372 (14) 2902/3372 (86) All 1588 (47) 82/1588 (5) 1506/1588 (95) 807 (24) 187/807 (23) 620/807 (77) 530 (16) 132/530 (25) 398/530 (75) Corticosteroids, 1085 (32) 149/470 936/2902 Non-biologic DMARDs, 713 (21) 66/470 647/2902 (22) Delivery Year, 2011-2013 1202 (36) 224/1202 (19) 978/1202 (81) 510 (15) 36/510 (7) 474/510 (93) 345 (29) 96/345 249/345 (72) 200 (6) 61/200 (30) 139/200 (70) 1138 (34) 148/1138 (13) 990/1138 549 20/549 (4) 529/549 (96) 266 (8) 60/266 206/266 157 41/157 (26) 116/157 (74) 1032 (31) 98/1032 (9) 934/1032 (91) 529 26/529 503/529 196 31/196 165/196 (84) 173 30/173 (17) 143/173 (83) Acknowledgements This funded by Canadian Institutes Health Research (CIHR) project grant awarded EV. LKF supported CIHR Canada Graduate Scholarships Doctoral Award. EV salary support award Arthritis Society. Disclosure Interests None Declared.