Table 2

Association of pregnancy and lupus flares defined by PGA*: the Hopkins Lupus Cohort, 1987–2015 (n=1349)

FlaresPYCrude incidence per 100 PYCrude IRR (95% CI)Stratified Cox†
HR (95% CI)
12-month postpartum period
 All patients (n=1349)
  Not pregnant/postpartum22465583.240.21.0 (ref)1.0 (ref)
  Pregnancy134220.860.71.51 (1.27 to 1.80)1.59 (1.27 to 1.96)
  12 months postpartum148370.939.90.99 (0.84 to 1.17)1.02 (0.83 to 1.25)
 Patients with ≥1 observed pregnancy in the cohort (n=304)
  Not pregnant/postpartum6421790.435.91.0 (ref)1.0 (ref)
  Pregnancy134220.860.71.69 (1.40 to 2.04)1.88 (1.48 to 2.49)
  12 months postpartum148370.939.91.11 (0.93 to 1.33)1.24 (0.96 to 1.66)
3-month postpartum period
 All patients (n=1349)
  Not pregnant/postpartum23365786.340.41.0 (ref)1.0 (ref)
  Pregnancy134220.860.71.50 (1.26 to 1.79)1.57 (1.26 to 1.92)
  3 months postpartum5895.660.71.50 (1.16 to 1.95)1.48 (1.07 to 1.95)
 Patients with ≥1 observed pregnancy in the cohort (n=304)
  Not pregnant/postpartum7321993.536.71.0 (ref)1.0 (ref)
  Pregnancy134220.860.71.65 (1.38 to 1.99)1.79 (1.40 to 2.42)
  3 months postpartum5895.660.71.65 (1.26 to 2.16)1.71 (1.11 to 2.52)
  • *Flare defined as change in ≥1 from PGA score at previous visit.

  • †Stratified Cox model is a conditional model that does not assume independence of multiple events of flares and allows different baseline hazards based on the number of previous flares a patient experienced.

  • IRR, incidence rate ratio; PGA, Physician Global Assessment of disease activity; PY, person-years.