SLE Pregnancy Outcomes Impacted by Maternal Race, Ethnicity

Black and Hispanic women with systemic lupus erythematosus (SLE) have significantly increased odds of experiencing preterm birth, preeclampsia, maternal morbidity, and higher hospital expenses when compared with white women, according to research published in Arthritis Care & Research.

Megan E.B. Clowse, MD, MPH, associate professor of medicine at Duke University in Durham, North Carolina, and Chad A Grotegut, MD, MHSc, a maternal-fetal medicine specialist at Duke Health, used the Nationwide Inpatient Sample (NIS) from 2008-2010 to identify pregnancy delivery discharges and compare pregnancy outcomes among women with SLE by maternal race and ethnicity.

Data included information from 20% of discharges at more than 1000 US hospitals, organized according to International Classification of Diseases, Ninth Revision (ICD-9) codes.Separate analyses were performed separately for black vs white women and Hispanic vs white women.

Drs Clowse and Grotegut assessed 13,553 deliveries to mothers with SLE and 12.5 million deliveries to mothers without SLE that occurred between 2008 and 2010. Among all women, pregnancies in patients with SLE accounted for 1.04, 1.84, and 0.88 per 1000 deliveries in white, black, and Hispanic deliveries, respectively.

 Preexisting conditions,including chronic hypertension and chronic renal failure,and obstetric complications were more common in black and Hispanic populations. 

Cesarean-section delivery was common among women with SLE, with preterm labor occurring in 14.3% of white deliveries, 24.7% of black deliveries, and 20.6% of Hispanic deliveries.

After multivariate analysis, the researchers found that both black and Hispanic women still faced higher rates of preeclampsia, preterm labor, and fetal growth restriction compared with white women. 

Additionally, Hispanic women were found to have higher odds of postpartum hemorrhage, while black women had higher rates of stillbirth, premature membrane rupture, and chorioamnionitis.

High odds of pregnancy complications in both groups were found to correspond to higher average hospital charges per delivery hospitalization; for example, non-lupus pregnancies in black women cost 10% more and in Hispanic women cost 19% more than in non-lupus white women. Lupus pregnancies were 19% and 42% more expensive for black and Hispanic women, respectively, than white women with SLE.

Summary and Clinical Applicability

“This study demonstrates an area of lupus pregnancy that has been largely neglected, and suggests a new avenue to improve overall pregnancy outcomes for women with lupus,” wrote Drs Clowse and Grotegut. They note that small cohorts collected from specialized clinics may not reveal the same racial disparity identified in this study.

The researchers note that one likely cause for the disparities is racial differences found in lupus outside of pregnancy. Lupus nephritis (LN) is more common in and more severe in both black and Hispanic women, and LN—either prior or current—is a key predictor of both preeclampsia and preterm birth. 

Limitations and Disclosures

• SLE diagnoses were based on discharge diagnosis and hospital coding;as such SLE may have been overdiagnosed in some pregnancies and underdiagnosed in others
• SLE diagnoses were not all confirmed via chart review, due to limited data provided by the NIS 

• The inability to obtain infant outcomes or gestational age at delivery prevents an analysis of preterm delivery

• Degree of lupus activity and medications taken during pregnancy were unable to be determined, due to lack of data
• Associations, not causes, are identified within this study 

Reference

Clowse MEB, Grotegut CA. Racial and ethnic disparities in the pregnancies of women with systemic lupus erythematosus. Arthrit Care Res. 2016;68(10):1567-1572. doi: 10.1002/acr.22847

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