Table 4.
ModificationA by hydroxychloroquine of hazard ratios for the association of pregnancy and lupus flares: the Hopkins Lupus Cohort, 1987–2015 (n=1349).
| Patients Exposed to HCQ | Patients Unexposed to HCQ | |||||||
|---|---|---|---|---|---|---|---|---|
|
| ||||||||
| Flares | PY | Crude Incidence per 100 PY | HRB (95% CI) | Flares | PY | Crude Incidence per 100 PY | HRB (95% CI) | |
|
| ||||||||
| PGAC | ||||||||
| 12-Month Postpartum Period | ||||||||
| Not pregnant/postpartum | 1458 | 3843.0 | 38.0 | 1.0 (ref) | 788 | 1740.3 | 45.3 | 1.0 (ref) |
| Pregnancy | 52 | 123.4 | 42.1 | 1.26 (0.88, 1.69) | 82 | 97.3 | 84.3 | 1.83 (1.34, 2.45) |
| 12-months postpartum | 75 | 212.2 | 35.3 | 1.02 (0.72, 1.32) | 73 | 158.7 | 46.0 | 0.98 (0.67, 1.31) |
| 3-Month Postpartum Period | ||||||||
| Not pregnant/postpartum | 1510 | 3967.3 | 38.1 | 1.0 (ref) | 826 | 1819.0 | 45.4 | 1.0 (ref) |
| Pregnancy | 52 | 123.4 | 42.1 | 1.24 (0.86, 1.73) | 82 | 97.3 | 84.3 | 1.84 (1.37, 2.44) |
| 3-months postpartum | 23 | 51.6 | 44.6 | 1.25 (0.71, 1.87) | 35 | 44.0 | 79.5 | 1.63 (1.04, 2.39) |
| SELENA-SLEDAID | ||||||||
| 12-Month Postpartum Period | ||||||||
| Not pregnant/postpartum | 1765 | 3843.0 | 45.9 | 1.0 (ref) | 876 | 1740.3 | 50.3 | 1.0 (ref) |
| Pregnancy | 64 | 123.4 | 51.9 | 1.35 (0.92, 1.81) | 76 | 97.3 | 78.1 | 1.59 (1.17, 2.09) |
| 12-months postpartum | 100 | 212.2 | 47.1 | 1.13 (0.88, 1.44) | 70 | 158.7 | 44.1 | 0.91 (0.64, 1.20) |
| 3-Month Postpartum Period | ||||||||
| Not pregnant/postpartum | 1834 | 3967.3 | 46.2 | 1.0 (ref) | 914 | 1819.0 | 50.2 | 1.0 (ref) |
| Pregnancy | 64 | 123.4 | 51.9 | 1.32 (0.91, 1.79) | 76 | 97.3 | 78.1 | 1.61 (1.20, 2.10) |
| 3-months postpartum | 31 | 51.6 | 60.1 | 1.53 (0.96, 2.25) | 32 | 44.0 | 72.7 | 1.45 (0.87, 2.11) |
To test whether effects were similar for hydroxychloroquine (HCQ) users and non-users, an interaction term between each medication with the exposure was included in the model. Effect measure modification was determined by likelihood ratio test (α=0.20).
Estimated by stratified Cox model, 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
Flare defined as change in ≥1 from PGA score at previous visit
Flare defined as change in ≥4 from SELENA-SLEDAI score at previous visit
CI: confidence interval; HCQ: hydroxychloroquine; HR: hazard ratio; PGA: Physician Global Assessment of disease activity; PY: person-years; SLE: systemic lupus erythematosus; SLEDAI: SLE Disease Activity Index