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Highlights from

American College of Rheumatology

annual meeting 2018

Chicago, Illinois 19-24 October 2018

Faster decline in maternal mortality in SLE patients as compared with non-SLE patients

Take-home messages
  • Maternal mortality in SLE pregnancies decreased by 93% between 1998-2015 (faster decline in maternal mortality in SLE patients as compared with non-SLE patients)
  • African-American and low-income pregnant SLE patients did consistently worse than Caucasian and high-income pregnant SLE patients
  • All groups improved over time and there was no difference in the pace of improvement with regards to racial or socioeconomic status
“We are doing something right in lupus management with better guidelines, better medications and people are increasingly aware that lupus pregnancies can be managed with some expertise.”

Dr Bella Mehta Rheumatologist, Hospital for Special Surgery in New York, US

Maternal mortality in systemic lupus erythematosus (SLE) has shown a significant and faster decline compared with that seen in non-SLE pregnancies, according to the largest study to date of lupus pregnancies in the US.

The findings refer to data recorded between 1998-2015. Upon subgroup analysis, no difference was seen in the pace of improvement regarding racial and socio-economic status, which argues against a selective lack of improvement in any certain disparity group.

Dr Bella Mehta, a rheumatologist at the Hospital for Special Surgery in New York, US, and the study’s co-author, presented the findings at the 2018 American College of Rheumatology/ Association of Rheumatology Health Professionals (ACR/ARHP) Annual Meeting.

“Our study is consistent with previous studies that have found SLE pregnancies are more likely to have a higher burden of medical and obstetric complications,” said Dr Mehta, adding that, “among SLE pregnancies, the improvement in maternal mortality was our most surprising and encouraging finding, with 93% decrease over the 18-year period.

By comparing the lupus and non-lupus pregnancy outcomes, the researchers saw that the lupus improvements were better and faster than general pregnancy outcome improvements - which were good too. “We are doing something right in lupus management with better guidelines, better medications and people are increasingly aware that lupus pregnancies can be managed with some expertise,” she remarked.

However, she added, “African Americans and women from low-income areas have overall worse maternal and foetal mortality, but the outcomes were found to have improved in all groups across the 18-year period.”

For women with SLE, pregnancy has long been considered high risk and associated with both medical and obstetric complications. Certain groups of SLE patients have particularly worse pregnancy outcomes than others, including African Americans and the socio-economically impoverished. “But whether racial and socio-economic disparities have changed in SLE pregnancy outcomes was not known,” said Dr Mehta, explaining some of the rationale for the study. “In this study we aimed to assess nationwide temporal trends of inpatient maternal and foetal complications in SLE pregnancies over the past 18 years in the US, and to investigate whether there were racial and socio-economic disparities in SLE pregnancies, and if they changed over time.”

Retrospective trends of cross-sectional data including diagnoses and procedures, pregnancy-related admissions, with or without SLE, were drawn from the National Inpatient Sample (NIS) database between the years 1998-2015. The NIS represents over 95% of all US hospitalisations, equating to approximately 35 million per year. Complications analysed included: maternal mortality, caesarean section, pre-eclampsia or eclampsia, length of stay, and inflation-adjusted hospital charges. “You may think that pregnancy is predominantly an outpatient issue, but the literature suggests that 99.4% delivery happens in the hospital in the US, and likewise most of the acute serious complications. That is how we managed to catch the cohort here,” remarked Dr Mehta.

The study included 72,505,567 pregnancy-related admissions, and of these, 93,820 pregnant women had SLE. In terms of demographics, SLE patients were older, and had a higher proportion of African Americans, higher maternal mortality, and higher intrauterine foetal death compared with those without SLE.

Outcomes were multiple, including maternal mortality (in-hospital death per 100,000 admissions) and foetal mortality (intrauterine foetal death or stillbirth), pre-eclampsia, eclampsia, caesarean section, non-delivery admissions and length of stay. Dr Mehta focused on maternal and foetal mortality in her presentation. In particular, the researcher analysed temporal trends by year to see how outcomes changed over time.

Showing the demographics of women included in the study, Dr Mehta said, “We can see that those with lupus had more non-delivery admissions, which means that they were more likely to be hospitalised for the management of acute complications.” For non-delivery admissions, 7% were in non-SLE pregnancies versus 19% in SLE pregnancies.

In terms of outcomes across the 18 years of the study, maternal mortality had an incidence of 12 per 100,000 admissions in non-SLE pregnancies versus 180 per 100,000 admissions in SLE pregnancies. Foetal mortality was 0.7% versus 1.8% in non-SLE and SLE pregnancies respectively. “For maternal mortality, in particular, those with lupus have a mortality 15 times higher than non-lupus populations,” explained Dr Mehta.

Looking specifically at outcomes in SLE pregnancies in African-American women compared with Caucasian women, Dr Mehta highlighted that there were more non-delivery admissions at 27.4% in African Americans versus 14.2% in Caucasians (p<0.001). Maternal mortality per 100,000 admissions was 265 versus 87 (p=0.019) in African-American and Caucasian women respectively; foetal mortality was 2.0% versus 1.1% (p<0.001) “You can see that women who are African American have overall worse outcomes than women who are Caucasian.”

In terms of the low versus highest income quartile, Dr Mehta remarked that, “women from low-income areas have overall worse outcomes compared to those from high-income areas.” Of note, maternal mortality in the lowest income quartile versus the highest income quartile was 242 per 100,000 admissions versus 133 (not statistically significant, p=0.196) respectively; foetal mortality in the lowest income quartile versus the highest income quartile was 2.3% versus 1.5% (p=0.007).

“Here is what our study is primarily about, that is, the temporal trends of maternal and foetal mortality,” reported Dr Mehta. “In 1998 to 2000, the maternal mortality in lupus pregnancies was roughly 450 per 100,000 admissions, which is 34 times higher than non-lupus pregnancies; whereas in 2013 to 2015, the maternal mortality was 25 per 100,000 admissions, which is only 2.5 times higher than non-lupus pregnancies (p=0.002). So there has been a 93% decrease in maternal mortality in lupus pregnancies. Maternal mortality in lupus pregnancies is almost at the point of merging with non-lupus pregnancies. I think it is very encouraging to say that we are at the edge of closing the gap.”

Regarding foetal mortality, it also appears to show a downward trend. In 1998-2000, foetal mortality in lupus pregnancies was 2.5%, while in 2013-2015, foetal mortality dropped to 1.5%. However, in comparison with non-lupus pregnancies, the trend differences were non-significant, noted Dr Mehta.

In terms of social and racial disparity differences in SLE pregnancies, overall, there were no statistically significant trend differences in either maternal mortality or foetal mortality outcomes, between African-American and Caucasian populations, or between highest and lowest income quartile areas. “This means that all these subgroups improved, rather than a selective lack of improvement in certain vulnerable populations. In foetal mortality, for example, there appears to be a significant gap between African Americans and Caucasians in early years of our study, while the gap became very small in later years of our study,” said Dr Mehta.

Based on Luo Y, Xu J, et al. Pregnancy in lupus: 17-year U.S. nationwide trend in obstetric and maternal outcomes (abstract 1852). Presented on Monday 22 October 2018.

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