139. Disease flares during pregnancy and postpartum in patients with systemic lupus erythematosus

Introduction Prior studies found conflicting results about whether lupus is likely to flare during or after pregnancy. Understanding the effect pregnancy has on disease activity is clinically significant for the patient. Objective Using a large cohort of pregnant and non-pregnant women with lupus, we measured the effect of pregnancy on disease flares in systemic lupus erythematosus and estimated modification by hydroxychloroquine (HCQ) use. Methods Data were prospectively collected in the Hopkins Lupus Cohort 1987–2015. Women aged 14–45 years with u003e1 measurement of disease activity were included. The time-varying exposures were classified as pregnancy, postpartum, or non-pregnant/non-postpartum periods. Two postpartum times periods were analyzed: 3 months and 12 months. Flares were defined as change in Physician Global Assessment (PGA) ⩾1 from previous visit. A stratified Cox model estimated hazard ratios with bootstrap 95% CIs. Results There were 1349 patients, including 398 pregnancies in 304 patients. There was an increased rate of flare during pregnancy (HR: 1.59; 95% CI: 1.27, 1.96), however this effect was modified by HCQ use, with the HR of flares in pregnancy compared to non-pregnant/non-postpartum periods estimated to be 1.83 (95% CI: 1.34, 2.45) for patients with no HCQ use and 1.26 (95% CI: 0.88, 1.69) for patients with HCQ use. The risk of flare was similarly elevated among non-HCQ users in the 3-months postpartum (HR: 1.63; 95% CI: 1.04, 2.39), but not among women taking HCQ (HR: 1.25; 95% CI: 0.71, 1.87). There was no increased risk of flare during the 12-month postpartum period, with no modification by HCQ. Discussion Our study supports and extends previous findings that the incidence of flare is increased during pregnancy and within the 3-months postpartum. Continuing HCQ, however, appeared to mitigate the risk of flare during and after pregnancy. No increased rate of flare was observed during a 12-month postpartum period.