Table 3.
Association between exposures before day 140 and preterm birth for RA (n = 524)
| Medication exposure before gestational Day 140a | n | Preterm birth | % Preterm birth | Crude RR (95% CI) | Adjusted RRb (95% CI) | Mutually adjusted RRc (95% CI) |
|---|---|---|---|---|---|---|
| Oral corticosteroid | ||||||
| High dose trajectory | 15 | 10 | 66.7 | 6.92 (4.15, 11.55) | 4.77 (2.76, 8.26) | 4.74 (2.72, 8.25) |
| Medium dose trajectory | 122 | 28 | 23.0 | 2.38 (1.46, 3.89) | 1.81 (1.10, 2.97) | 1.87 (1.13, 3.10) |
| Low dose trajectory | 117 | 17 | 14.5 | 1.51 (0.85, 2.67) | 1.38 (0.79, 2.38) | 1.38 (0.80, 2.40) |
| No oral corticosteroid | 270 | 26 | 9.6 | Reference | Reference | Reference |
| B-DMARD | 354 | 55 | 15.5 | 1.02 (0.66, 1.56) | 1.08 (0.70, 1.66) | 1.07 (0.71, 1.61) |
| No B-DMARD | 170 | 26 | 15.3 | Reference | Reference | Reference |
| NB-DMARD | 161 | 23 | 14.3 | 0.89 (0.57, 1.40) | 0.87 (0.55, 1.38) | 0.85 (0.55, 1.30) |
| No NB-DMARD | 363 | 58 | 16.0 | Reference | Reference | Reference |
| No medication of interest | 56 | 4 | 7.1 | NA | NA | NA |
Mutually exclusive oral corticosteroid trajectory groups and any vs none B-DMARD and NB-DMARD exposure groups.
One model for each medication of interest. RR adjusted for quintiles of the propensity score: last menstrual period year (<2009, ≤2009), maternal age, race and ethnicity (Non-Hispanic White, Other), multiple gestation, ≥5 servings of alcohol in the first trimester, autoimmune disease comorbidity (IBD, lupus or ankylosing spondylitis), non-steroidal anti-inflammatory drug use before gestational day 140 (any, none), and HAQ Disability Index, pain score and global score at enrolment.
One model, adjusting for each medication exposure group of interest and each associated propensity score.
B-DMARD, biologic disease modifying antirheumatic drug; NB-DMARD, non-biologic disease-modifying antirheumatic drug; RR, risk ratio.