Effect of remission, clinical remission with active serology, and glucocorticoid dosage on the pregnancy outcome of pregnant patients with systemic lupus erythematosus

Background Remission is a key treatment target in systemic lupus erythematosus (SLE) management. Given the direct correlation between lupus flares and elevated risks of adverse pregnancy outcomes (APOs), securing remission before conception becomes crucial. However, the association between clinical remission with active serology, and the risk of APOs is not thoroughly understood. Additionally, determining the optimal glucocorticoid dosage during pregnancy to mitigate APO risks remains under-researched. This study investigated the risk of APOs in relation to remission/serological activity status in patients in clinical remission/glucocorticoid dosage. Methods Pregnant patients with SLE, who were followed up at two Japanese tertiary referral centers, and had their remission status assessed at conception, were included in this study. We categorized the patients into two groups based on whether they achieved Zen/Doria remission at conception and analyzed the APO ratio. We also examined the influence of serological activity in pregnant patients with clinical remission and analyzed the optimal glucocorticoid dosage to minimize the APO ratio. Results Of the 96 pregnancies included, 59 achieved remission at conception. Pregnant patients who achieved remission showed a significant decrease in the APO ratio compared with those who did not. (overall APO: odds ratio (OR) 0.27, 95% confidence interval (CI) 0.11-0.65, p < 0.01, maternal APO: OR 0.34, 95%CI 0.13-0.85, p = 0.021, neonatal APO: OR 0.39, 95%CI 0.17-0.90, p = 0.028). Conversely, no statistical difference was observed in the APO ratio based on serological activity in pregnant patients with clinical remission. (overall APO: OR 0.62, 95%CI 0.21-1.79, p = 0.37, maternal APO: OR 1.25, 95%CI 0.32-4.85, p = 0.75, neonatal APO: OR 0.83, 95%CI 0.29-2.39, p = 0.73). A glucocorticoid dose of prednisolone equivalent >= 7.5 mg/day at conception correlated with increased APO. (overall APO: OR 3.01, 95%CI 1.23-7.39, p = 0.016, neonatal APO: OR 2.98, 95% CI:1.23-7.22, p = 0.016). Conclusions Even with active serology, achieving clinical remission can be a clinical target for reducing APOs in patients who wish to conceive. In addition, if clinically feasible, reducing the glucocorticoid dosage to < 7.5 mg/day before conception could be another predictive factor.