Pregnancy outcomes and risk factors for thrombocytopenia in pregnant patients with systemic lupus erythematosus.

Abstract

Background: To compare pregnancy outcomes between systemic lupus erythematosus (SLE) patients with thrombocytopenia and those without, and to develop a nomogram for assessing the risk of developing SLE-related thrombocytopenia during pregnancy.

Methods: Clinical data from 178 pregnant patients with SLE were analyzed. Patients were classified into thrombocytopenia and normal platelet groups using a platelet count cutoff of < 100 × 10^9/L. Pregnancy outcomes were compared between these groups. A nomogram was developed to identify factors associated with thrombocytopenia based on univariate and multivariable logistic regression analyses. The performance of the nomogram was assessed through receiver operating characteristic (ROC) curves, calibration curves, and decision curve analysis (DCA).

Results: Among the 178 patients, 34 were in the thrombocytopenia group and 144 in the normal platelet group. SLE patients with thrombocytopenia had a significantly higher rate of active disease (55.9% vs. 5.6%, P < 0.001) and a higher SLE-Pregnancy Disease Activity Index (SLEPDAI) (4.71 ± 3.04 vs. 2.29 ± 1.88, P < 0.001). When comparing patients with thrombocytopenia (categorized by platelet counts < 50 × 10^9/L and > 50 × 10^9/L) to the control group, the incidence of severe preeclampsia (20.00% vs. 15.79% vs. 4.86%, P = 0.027) and postpartum hemorrhage (26.32% vs. 6.67% vs. 3.47%, P = 0.007) was also significantly higher in the thrombocytopenia group. This group exhibited elevated rates of pregnancy loss (73.33% vs. 31.58% vs. 4.17%, P < 0.001) and stillbirth (20.00% vs. 15.79% vs. 0.69%, P < 0.001). Active disease, previous abortion, and anti-β2GPI antibodies positivity were identified as independent factors of developing SLE-related thrombocytopenia during pregnancy. The area under the curve for the nomogram was 0.833 (95% CI: 0.753-0.913). Both the calibration curve and DCA indicated that the model performed well.

Conclusion: Thrombocytopenia in pregnant patients with SLE is associated with increased disease activity and a higher incidence of adverse outcomes, including pregnancy loss and stillbirth. The nomogram for developing thrombocytopenia during pregnancy may help clinicians improve the management of this group of patients.

Clinical trial number: not applicable.