High and Low HCQ Levels During Pregnancy Linked to Preterm Birth, Disease Activity in SLE

Both high and low hydroxychloroquine (HCQ) levels have been associated with preterm birth and disease activity among women with systemic lupus erythematosus (SLE), according to the results of an observational study published in The Journal of Rheumatology.

Because pregnancy can cause significant physiologic changes that may alter HCQ levels and lead to therapeutic failure, the investigators sought to assess HCQ concentrations during pregnancy in women with rheumatic diseases. Patients with rheumatic diseases who had been taking HCQ prior to their pregnancy were identified between November 2013 and December 2016. Serum samples from participants were analyzed if they had continued HCQ longitudinally throughout their pregnancy. Primary HCQ exposure was classified as either nontherapeutic (≤100 ng/mL) or therapeutic (>100 ng/mL).

A total of 100 samples from 50 patients with rheumatic disease were analyzed, 56% of whom had SLE. At each trimester, HCQ levels varied considerably. The mean physician’s global assessment scores in women with SLE were significantly higher among those with average drug levels ≤100 ng/mL compared with those with levels >100 ng/mL (0.93 vs 0.32, respectively; P =.01).

Among women with SLE, 83% with average HCQ concentrations ≤100 ng/mL delivered prematurely (n=6), compared with only 21% of those with average HCQ levels >100 ng/mL (n=19; P =.01). Moreover, among patients without SLE, HCQ concentrations were not associated with prematurity or disease activity.

The investigators concluded that additional research is warranted to more clearly comprehend HCQ disposition throughout pregnancy and to elucidate the relationship between drug levels and patient outcomes. With disease activity and pregnancy demonstrating significant associations with preterm birth and low neonatal gestational age, this highlights the importance of controlling active disease during pregnancy among women with rheumatic diseases.

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Reference

Balevic SJ, Cohen-Wolkowiez M, Eudy AM, Green TP, Schanberg LE, Clowse MEB. Hydroxychloroquine levels throughout pregnancies complicated by rheumatic disease: implications for maternal and neonatal outcomes [published online October 1, 2018].  J Rheumatol. doi: 10.3899/jrheum.180158