SAN DIEGO – Pregnancy in patients with vasculitis had a higher risk for preterm delivery and preeclampsia/eclampsia – especially those with small-vessel vasculitis – compared with the general obstetric population, in a large analysis of administrative claims data presented at the American College of Rheumatology annual meeting.
“We suspect that there is a relationship between the increased risk of these serious hypertensive disorders and preterm delivery, given the higher risk of medically indicated preterm delivery,” one the of the study authors, Audra Horomanski, MD, said in an interview prior to her presentation in a plenary session at the meeting.
Limited data exist on the risks of pregnancy in patients with systemic vasculitis, according to Dr. Horomanski, a rheumatologist who directs the Stanford Vasculitis Clinic at Stanford (Calif.) University. “The majority of what we do know comes from relatively small cohort studies,” she said. “This is the first U.S., nationwide database study looking at the risk of preterm delivery and other adverse pregnancy outcomes.”
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Dr. Audra Horomanski
Drawing on administrative claims data from private health insurance providers, Dr. Horomanski and her colleagues identified all pregnancies regardless of outcome for patients with and without vasculitis from 2007 to 2021. They defined vasculitis as ≥ 2 ICD-coded outpatient visits or ≥ 1 ICD-coded inpatient visit occurring before the estimated last menstrual period (LMP), and they further categorized vasculitis by vessel size: large, medium, small, and variable, based on Chapel Hill Consensus Conference criteria. For a referent population, they included patients without vasculitis or other rheumatic disease, defined as no ICD-coded outpatient or inpatient visits for vasculitis, systemic lupus erythematosus, rheumatoid arthritis, systemic sclerosis, or juvenile idiopathic arthritis before LMP or during pregnancy. Next, the researchers described pregnancy outcomes in patients with vasculitis compared with the referent population, and explored pregnancy characteristics and complications in patients with vasculitis stratified by parity (nulliparous vs. multiparous).
Dr. Horomanski reported results from 665 pregnancies in 527 patients with vasculitis and 4,209,034 pregnancies in 2,932,379 patients from the referent population. Patients with vasculitis had higher rates of spontaneous abortion (21% vs. 19%), elective termination (6% vs. 5%), ectopic and molar pregnancy (4% vs. 3%), and preterm delivery (13% vs. 6%). Approximately 12% of pregnancies among patients with vasculitis were complicated by preeclampsia. Multiparous pregnancies had a slightly higher frequency of preterm delivery than did nulliparous pregnancies (14% vs. 13%) and were more often comorbid with gestational diabetes (11% vs. 6%) and prepregnancy hypertension (23% vs. 13%). Patients with small-vessel vasculitis had higher frequencies of spontaneous abortion, preterm delivery, and comorbidities among vasculitis subtypes.
“I was surprised that vasculitis patients were less likely to be diagnosed with gestational hypertension compared to the general population, but more likely to be diagnosed with preeclampsia/eclampsia,” Dr. Horomanski added. “It raises questions about whether vasculitis patients are more likely to be diagnosed with more serious hypertensive disorders of pregnancy due to their underlying systemic disease or due to the perceptions of the treating clinicians.”
She acknowledged certain limitations of the study, including the fact that it lacked information on race and ethnicity and was limited to privately insured individuals. This “suggests that we are likely missing patients with disabilities and those who are uninsured, both groups that may be at higher risk for adverse pregnancy outcomes,” she said. “We also have no information on disease activity or flare events which may contribute to these outcomes, particularly medically indicated preterm delivery. There is also a risk of misclassification due to the use of claims data and ICD coding. This misclassification may impact vasculitis diagnoses, parity, and early pregnancy losses.”
Despite the limitations, she said that the work “highlights the value of large database analysis as a complement to prior cohort studies to further clarify this complex picture. Overall, this information is valuable for the counseling of vasculitis patients considering pregnancy and for creating a plan to monitor for pregnancy complications.”
Lindsay S. Lally, MD, a rheumatologist with Hospital for Special Surgery in New York, who was asked to comment on the study, characterized the findings as “important in how many women with vasculitis and vasculitis pregnancies were identified. These data are a start at heightening our awareness about potential complications these women may experience during pregnancy. This study should help inform our family planning conversations with our vasculitis patients. Discussing potential reproductive risks, which are likely mediated by the disease itself, as well as the treatments that we prescribe, is important to help our vasculitis patients make informed decisions.”
Hospital for Special Surgery
Dr. Lindsay S. Lally
Dr. Lally noted that an ongoing project through the Vasculitis Clinical Research Consortium includes a prospective registry of pregnant women with vasculitis, which asks pregnant patients to enter information throughout their pregnancy. “These studies will ultimately help optimize care of our vasculitis patients during pregnancy, ensuring the best outcomes for mother and baby,” she said.
Dr. Horomanski disclosed that she has received research support from Principia, BeiGene, Gilead, and the National Institutes of Health. Dr. Lally reported having no relevant financial relationships.
A version of this article appeared on Medscape.com.