Page 34 - Fertility in Women with Rheumatoid Arthritis Vruchtbaarheid van vrouwen met reumatoïde artritis

Chapter 2
Figure 2 – Survival curves showing the time to pregnancy (TTP) in rheumatoid arthritis (RA) patients with (A) various levels of disease activity and (B) different prednisone dosages. When the TTP exceeded 1 year, patients were considered subfertile. If women had not become pregnant at the last time of contact, the TTP was considered censored at the date of the last visit. (A) Patients with high disease activity (DAS28>5.1) had a longer TTP than patients in the other groups (3.2<DAS28≤5.1, p=0.03; 2.6<DAS28≤3.2, p=0.04; DAS28<2.6, p=<0.001). Patients with intermediate disease activity (3.2<DAS28≤5.1) had a longer TTP than patients with RA in remission (DAS<2.6; p=0.008), but TTP did not differ signi cantly from that in patients with low disease activity (2.6<DAS28≤3.2). The TTP in patients with low disease activity did not differ signi cantly from that in patients in remission. (B) Patients using high prednisone dosages had a longer TTP than patients using low dosages (p=0.04), and a longer TTP than patients using no prednisone (p=0.002). The TTP between the low-dose group and the group with no prednisone did not differ signi cantly. DAS28, 28-joint Disease Activity Score.
Cox regression
Cox regression analysis with multiple variables showed that older age, nulliparity, higher DAS28, preconception use of NSAIDs, and preconception use of prednisone were associated with a longer TTP (table 3). Smoking, time since RA diagnosis, RF positivity, ACPA positivity, past MTX use, and preconception sulfasalazine use were not signi cantly associated with TTP.
When analysis was restricted to pregnancies resulting in a live birth, the same factors were identi ed as signi cantly associated with TTP (data not shown).
Because DAS28 and prednisone use may show interaction, we introduced an interaction term (DAS28 x daily prednisone dosage) into our model. This showed no signi cant effect (HR 1.00, 95% CI 0.99 to 1.02; p=0.41).
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