Pos0882 Pregnancy Outcomes in Ra and Sle Patients: Analysis of the 2019 Nationwide Inpatient Sample Database

Background: Autoimmune connective tissue diseases (AICTD) are broadly thought to predispose affected pregnant women to elevated risk of adverse maternal and foetal outcomes, up to and including death. 1 However, this consensus relies on data that predates the modern and rapidly expanding therapeutic arsenal. The behaviour of two prototype AICTDs, rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE), differs in pregnancy, with RA tending towards quiescence 2 and SLE more often flaring 3, making them ideal conditions through which to study the effect of AICTD on pregnancy outcomes. Objectives: Assess pregnancy outcomes in patients with RA and SLE as compared to the general population and relative to one another. Methods: A retrospective cohort study was performed using de-identified data from the 2019 Nationwide Inpatient Sample Database. The study included adult patients (aged ≥18 years) hospitalized with a diagnosis of RA or SLE with a confirmed pregnancy. One control patient from the general population was matched for each case of RA or SLE using key demographic and clinical variables, including age, race, gender, and Elixhauser Comorbidity Index. Propensity scores were calculated using logistic regression. Chi-squared tests (for categorical outcomes) and t-tests (for continuous outcomes) were employed to identify statistically significant differences in the rates of various maternal and foetal outcomes between the RA, SLE, and matched control groups. A p-value of less than 0.05 was considered indicative of statistical significance. Results: There were a total of 961 RA pregnancies, 1042 SLE pregnancies and equal number of propensity matched controls respectively. There were significantly greater rates of preterm labour (7.49% v 4.61%, p=0.008) and lower rates of premature rupture of membranes (PROM) (8.73% v 11.61%, p=0.036) in SLE patients versus controls Table 1. There were greater rates of PROM (11.65% v 8.73%, p=0.03) but lower rates of pre-eclampsia (7.39% v 10.56%, p=0.014) and oligohydramnios (2.29% v 4.41%, p=0.009) in RA patients versus those with SLE. There were no statistically detectable differences in other examined outcomes. Table 1. Pregnancy outcomes in patients with RA and SLE as compared to the general population and relative to one another. Conclusion: Compared to prior data indicating poor pregnancy outcomes,1 our results reveal encouraging progress, with largely similar pregnancy outcomes in RA and SLE patients as compared to matched controls and one another. Improvements in rheumatological treatment and modern obstetrical care may have contributed to this leveling of the previously tilted playing field. Those pursuing pregnancies with AICTD are likely to have lower disease activity/remission, which can explain the largely similar outcomes among the groups studied. However, SLE patients remain 1.6 times more likely to experience preterm labor than controls. An explanation for the observed lower incidence of PROM in SLE patients when compared to general population and RA patients may lie in either there is no difference at all since the SLE and RA patients were not matched for confounding variables related to PROM versus the innate differences in the response to pregnancy in both diseases, or the pathophysiology of membrane rupture itself. Further prospective studies are needed to assess this finding and whether there are unaccounted confounding factors. Multidisciplinary care with rheumatology and obstetrics and a better understanding of the changes in SLE and RA patients during pregnancy is needed to further improve outcomes. REFERENCES: 1 Singh M, Wambua S, Lee SI, et al. Autoimmune diseases and adverse pregnancy outcomes: an umbrella review. Lancet. 2023;402 Suppl 1:S84. 2 Barrett JH, Brennan P, Fiddler M, Silman AJ. Does rheumatoid arthritis remit during pregnancy and relapse postpartum? Results from a nationwide study in the United Kingdom performed prospectively from late pregnancy. Arthritis Rheum. 1999 Jun;42(6):1219-27. 3 Onuora S. Systemic lupus erythematosus: Incidence of flare is increased in pregnancy. Nat Rev Rheumatol. 2018 May;14(5):248. Acknowledgements: NIL. Disclosure of Interests: None declared.