Page 36 - Fertility in Women with Rheumatoid Arthritis Vruchtbaarheid van vrouwen met reumatoïde artritis

Chapter 2
Prednisone
The effect of prednisone usage on subfertility was further assessed. Eighty- ve patients used prednisone in dosages of 2.5–20 mg daily (median 7.5 mg). They were divided into two groups: a low-dose group (≤7.5 mg prednisone, n=44), and a high-dose group (>7.5 mg prednisone daily, n=41). In the high-dose group, 66% of women were subfertile compared to 43% in the low-dose group and 36% in the women who did not use prednisone. Kaplan-Meier curves showed a signi cant longer TTP in prednisone users versus non-users (p=0.005), and in high-dose users versus low-dose users (p=0.045) ( gure 2B). In the Cox regression with the complete variable list, a dummy variable was introduced to distinguish between low-dose prednisone and high-dose prednisone. The HR for low-dose use was not signi cant (0.83, 95% CI 0.57 to 1.21; p=0.33), but use of high-doseprednisonesigni cantlyextendedtheTTP,withanHRof0.50(0.33to0.76; p=0.001). The signi cance of other variables in the analysis did not change.
A subgroup analysis on patients with DAS28 <3.2 still showed a signi cant association between prednisone use and a longer TTP (HR 0.21, 95% CI 0.10 to 0.45; p<0.001).
DAS28 after 1 year
A subgroup of women who did not conceive within 12 months after the rst visit, were revisited after one year. In the 17 patients who were still actively trying to conceive, the DAS28 for this visit did not differ from the DAS28 1 year earlier (3.96±1.6 vs 3.91±1.8; p=0.85).
DISCUSSION
In this prospective cohort of female RA patients, we showed that a prolonged TTP in RA is related to older age, nulliparity, higher disease activity, and preconception use of NSAIDs and prednisone (>7.5 mg daily).
Forty-two percent of the patients had a TTP exceeding 12 months. This is much higher than the reported subfertility of 9-20% in the general population with a pregnancy wish in Western countries.15,16 The median TTP of 6 months in pregnant RA women in our study is signi cantly longer than in the general Western European population, where 50% of women have a TTP of 3 months and approximately 70% conceive within 6 months after starting unprotected intercourse.16
The fertility rates in this study are similar to those shown by other studies in female RA populations of reproductive age. The proportion of 42% of subfertile women in
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