Risk Assessment Model for Postpartum Venous Thromboembolism Prevention in Patients with Systemic Lupus Erythematosus

Abstract

Background Patients with Systemic Lupus Erythematosus (SLE) may be at increased risk for developing a venous thromboembolism (VTE), particularly in the postpartum period. The Royal College of Obstetricians and Gynaecologists (RCOG) guideline for postpartum VTE prophylaxis is often used to triage which patients should get VTE prophylaxis. In this RCOG guideline, a score ≥ 3 drives a formal recommendation for postpartum anticoagulation. RCOG is unique in its inclusion of “active SLE” as an actionable VTE risk factor (adding 3 points). We sought to determine if a cohort of postpartum patients with a known history of SLE a) qualify as having “active” SLE by standard rheumatologic criteria b) have other risk factors for VTE c) received the recommended prophylaxis based on RCOG VTE risk assessment scoring and d) had a postpartum VTE. Objective To assess the application of the RCOG venous thromboembolism (VTE) risk model on a cohort of postpartum patients with a history of Systemic Lupus Erythematosus (SLE). Study Design This is a secondary analysis of an ongoing patient registry of women with SLE from 2016-2022. There were 49 SLE patients with 55 pregnancies using Definitions of Remission in SLE (DORIS) criteria to determine SLE disease activity. RCOG risk assessment model scoring was calculated for each patient prior to and after delivery. The primary outcome was the qualification of “active SLE” by standard rheumatologic criteria and assessment of recommendations for VTE prophylaxis based on RCOG VTE risk assessment scoring. Data were analyzed using Fisher’s Exact test, chi-square test, and Mann-Whitney U test with significance defined as p<0.05. Results In the study cohort, 34 pregnancies (61.8%) were in DORIS remission at delivery. Twenty-one pregnancies (38.2%) were not and scored 3 points on the RCOG VTE risk model. Of these pregnancies, only 19% (n=4) were recommended for VTE prophylaxis by the obstetrical provider despite RCOG score ≥ 3. Only 35.7% (n=5) of pregnancies in DORIS remission, but with 3 points for non-SLE related VTE risk factors (n=14), were recommended for VTE prophylaxis. Of the 20 pregnancies in remission with an RCOG score < 3 after assessing all risk factors, 15% (n=3) were nevertheless recommended for VTE prophylaxis. No patients had a postpartum VTE regardless of therapy. Conclusion These data reveal a need to improve upon providing postpartum VTE prophylaxis to SLE patients not in remission while also recognizing a diagnosis of SLE alone should not equate with active disease. Moreover, SLE patients in remission may still warrant VTE prophylaxis if other non-SLE-related risk factors are present.