Comparison of participants and non-participants in the follow-up of the PARA study
| Current study | Non-participants | P value | ||
|---|---|---|---|---|
| Number of unique patients | n=128 | n=167 | ||
| Age§—years | 42.5±4.4 | 43.4±4.1 | 0.055‡ | |
| Age at last PARA episode—years | 32.0±3.9 | 32.8±3.9 | 0.11‡ | |
| Smoker during PARA study | 9 (7%) | 28 (17%) | 0.013* | |
| Missing | 2 (2%) | 4 (2%) | ||
| Number of episodes within PARA study | ||||
| 1 episode | 98 (77%) | 139 (83%) | ||
| 2 episodes | 24 (19%) | 24 (14%) | ||
| 3 episodes | 6 (5%) | 3 (2%) | ||
| 4 episodes | – | 1 (1%) | ||
| Obstetric history | ||||
| Never pregnant before PARA study | 73 (57%) | 93 (56%) | 0.91* | |
| Pregnant during last PARA episode | 117 (91%) | 120 (72%) | <0.001* | |
| Nulliparous at end of PARA study | 6 (4.7%) | 36 (22%) | <0.001* | |
| Disease Characteristics | ||||
| Duration of RA§—years | 15.6 (12.6–20.9) | 15.5 (13.1–20.5) | 0.88† | |
| Missing | – | 2 (1%) | ||
| Duration of RA at first PARA episode | 4.2 (2.0–9.6) | 4.7 (1.9–8.5) | 0.99† | |
| Missing | – | 2 (1%) | ||
| Presence of ACPA | 78 (61%) | 112 (67%) | 0.33* | |
| Presence of RF | 86 (67%) | 125 (75%) | 0.16* | |
| Presence of erosions | 77 (60%) | 100 (60%) | 0.61* | |
| Missing | 3 (2.3%) | 9 (6.4%) | ||
| Disease activity Score (DAS28) during last PARA episode | ||||
| Preconception | 3.6±1.3 | 3.8±1.2 | 0.17‡ | |
| Missing | 51(40%) | 54 (32%) | ||
| First trimester | 3.5±1.2 | 3.6±1.2 | 0.57‡ | |
| Missing | 37 (29%) | 70 (42%) | ||
| Last available DAS28 (non-pregnant) | 3.5±1.2 | 3.5±1.2 | 0.79‡ | |
| Missing | – | 4 (2%) | ||
*Fisher’s exact-test;
†Mann-Whitney U-test;
‡Student’s t test;
§At 1 January 2016.
PARA, pregnancy-induced amelioration of RA; RA, rheumatoid arthritis.