Background/Purpose: Antiphospholipid syndrome (APS) significantly increases risk of preeclampsia. It is assumed that APS is associated with a subset of severe preeclampsia, HELLP (Hemolysis; Elevated Liver enzymes; Low Platelet count) syndrome, and that APS-associated preeclampsia presents earlier and with increased severity compared to non-APS associated preeclampsia. However, little data exists that directly compares these groups of patients. Herein we compare clinical characteristics of patients with APS-associated preeclampsia to those of APS-negative preeclampsia patients.

Methods: We used the electronic medical record of a large academic medical system to identify adult APS patients with at least one preeclampsia episode between 2000-2018. APS diagnoses were confirmed using the updated Sapporo APS Classification, and preeclampsia diagnoses (including subsets of severe preeclampsia and HELLP) were classified according to American College of Obstetricians and Gynecologists guidelines. We identified control patients from the same electronic medical record with at least one episode of preeclampsia and negative laboratory testing for antiphospholipid antibodies at the time of the preeclampsia event.  Groups were compared with respect to demographic factors, clinical presentation and fetal outcomes (including intrauterine growth restriction, intrauterine fetal demise and infant mortality within the first week of life) using Student’s t test and Chi-Square test.

Results: We identified eight APS patients and 29 controls with at least one episode of preeclampsia during the study period (Table 1). APS patients had a mean age of 30 years, 100% were white and BMI was 32 ± 2 (mean ± SD). Controls had similar demographics, with the exception that only 59% of controls were white. Of the eight APS patients, 38% had a pre-existing APS diagnosis (all based on obstetric complications; no thrombotic history), 38% were triple-positive (positive lupus anticoagulant, anti-cardiolipin and anti-β2 glycoprotein antibodies), 38% had at least one prior episode of preeclampsia and 50% had systemic lupus (likely low disease activity based on review of laboratory studies, lack of significant proteinuria, and treatment with few/no lupus medications). Although both groups had similar rates of severe preeclampsia, APS patients were more likely to have preeclampsia associated with at least partial HELLP (75%) compared to non-APS controls (20.7%) (p=0.004). Further, APS patients had more severe liver involvement (p=0.028) and thrombocytopenia (p=0.018). There was a trend for less severe proteinuria in APS-associated preeclampsia (p=0.36). No significant differences were seen in maternal or fetal outcomes, although there was a trend for more frequent intrauterine growth restriction complicating pregnancies of women with APS. Both groups developed preeclampsia at similar gestational ages.

Conclusion: As compared with preeclampsia in the general population, APS-associated preeclampsia has a distinct clinical phenotype, more often presenting in association with HELLP. If verified by other studies, these clinical differences suggest the possibility that distinct disease mechanisms underlie APS-associated preeclampsia.

Preeclampsia_APS_V5

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/antiphospholipid-syndrome-associated-preeclampsia-is-defined-by-a-distinct-clinical-phenotype/