Hydroxychloroquine doesn’t seem to lower lupus preeclampsia risk

Researchers analyzed insurance data on 1,020 women over nearly a decade

Marisa Wexler, MS avatar

by Marisa Wexler, MS |

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The antimalarial agent hydroxychloroquine doesn’t appear to lower the risk of preeclampsia during pregnancy in women with lupus, a study reports.

The study, “Hydroxychloroquine in lupus pregnancy and risk of preeclampsia,” was published in Arthritis & Rheumatology.

Preeclampsia is a pregnancy complication marked by high blood pressure and signs of organ damage, such as high protein levels in the urine. Lupus, an autoimmune disease that disproportionately affects women, is an established risk factor for preeclampsia. Indeed, estimates indicate preeclampsia occurs in up to a third of lupus pregnancies.

Hydroxychloroquine, or HCQ, is an antimalarial treatment that’s commonly used to manage lupus. Since it’s safe during pregnancy, it’s often recommended for pregnant women with lupus to prevent disease flares.

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Hydroxychloroquine’s effect on preeclampsia

It’s not clear if HCQ reduces the risk of preeclampsia, prompting researchers in the U.S. to analyze a commercial insurance database of 1,020 women with lupus who became pregnant and gave birth between 2007 and 2016 to “investigate whether early-pregnancy HCQ use was associated with a lower risk of preeclampsia in lupus pregnancy.”

Since some patients were pregnant more than once during the period analyzed, 1,068 pregnancies were reviewed. About half of them occurred in women who were pregnant for the first time, and all were singleton, meaning only one baby was born.

Preeclampsia was documented in about 15% of the pregnancies. About half (52%) had prescription histories consistent with HCQ use in the first trimester. With these data, scientists conducted statistical analyses to compare the risk of preeclampsia in patients who were and weren’t taking HCQ.

No statistically significant differences in preeclampsia risk based on HCQ treatment were seen. Separate analyses for women who were pregnant for the first time or for those who’d been pregnant before found no significant association between using HCQ and preeclampsia in either group.

“We observed 15% of singleton deliveries to patients with SLE [systemic lupus erythematosus] were complicated by preeclampsia, but did not observe a reduction in risk of preeclampsia associated with HCQ use,” wrote the researchers, who emphasized that it’s impossible to definitively conclude that HCQ doesn’t affect the risk of preeclampsia. A statistically meaningful effect could be detected in a larger dataset, they said, noting if HCQ does affect the risk of preeclampsia, it’s probably pretty modest.

The study was limited by its reliance on insurance data, which is an imprecise proxy for measuring clinical outcomes, the scientists noted. Another limitation is the possibility of confounding by indication. That is, it’s possible that patients on HCQ during pregnancy were receiving the treatment because they had more severe disease, which could have influenced the results.

“To inform the evidence base of the association of HCQ with preeclampsia, additional large, prospective, population-based studies drawing from a diverse pool of patients with SLE during pregnancy are needed along with clinical trials,” the scientists wrote.