Comparative performance of lupus disease-activity indices during pregnancy to predict adverse obstetric outcomes: A colombian SLE cohort

ObjectiveTo compare the performance of five lupus disease-activity indices measured at a single retrospective pregnancy timepoint for discriminating a composite adverse obstetric outcome (AO), and to perform exploratory clinically interpretable categorical and renal-item analyses across indices.MethodsRetrospective cohort at a tertiary center in Bogotá, Colombia (2012-2024). For each pregnancy, one retrospective assessment with complete clinical and laboratory information required to compute all indices was selected. AO was defined as any of: preterm birth, miscarriage, stillbirth/early fetal death, preeclampsia/eclampsia, premature rupture of membranes, postpartum hemorrhage, thromboembolism, placental abruption, or maternal death. We calculated SLEPDAI, Lupus Activity Index in Pregnancy (LAI-P), modified SLAM (m-SLAM), SLE Disease Activity Score (SLE-DAS), and BILAG2004-P. Because the dataset was retrospective and selected on complete data, we treated categorical and renal-item analyses as exploratory.ResultsTwenty-nine pregnancies (28 women) were included; AO occurred in 18/29 (62.1%). The original continuous-score analyses showed overlapping confidence intervals across indices. Exploratory clinically interpretable analyses showed AO in 15/18 (83.3%) pregnancies with any BILAG2004-P A/B domain, 16/20 (80.0%) with SLEPDAI ≥3, and 13/14 (92.9%) with SLE-DAS >7.64. Exploratory renal analyses showed the clearest signals for BILAG2004-P renal A/B (13/14 vs 5/15; OR 26.0, 95% CI 2.61-259.31), SLEPDAI renal-item score >0 (13/13 vs 5/16; OR 56.45, 95% CI 2.81-1133.97), and the LAI-P renal item >0 (12/13 vs 6/16; OR 20.00, 95% CI 2.05-195.01).ConclusionIn this small single-center cohort, active lupus was associated with adverse obstetric outcomes across disease-activity instruments. However, the study is underpowered to detect meaningful differences in discrimination between indices. Renal activity remained the most clinically relevant organ-specific signal in exploratory analyses, but these findings should be interpreted cautiously and confirmed in larger longitudinal cohorts.