Pregnant Women With IBD Are More Likely to be Adherent to Biologic Therapies Than Other Medications

Sangmin Lee; Cynthia H. Seow; Kamala Adhikari; Amy Metcalfe

Disclosures

Aliment Pharmacol Ther. 2020;51(5):544-552. 

In This Article

Results

Selection of the study population is shown in Figure 1. There were 143 491 women who delivered a live or stillborn infant ≥20 weeks of gestation in Alberta, Canada between 2012 and 2015. Of these women, 370 (0.26%; 95% CI: 0.23%, 0.28%) met the validated case definition for IBD before pregnancy. Only 247 (66.8%; 95% CI: 61.8%, 71.4%) of these women had two consecutive maintenance IBD medications dispensed from community pharmacies in Alberta during the year prior to pregnancy. There were 179 (72.5%; 95% CI: 66.5%, 77.7%) women who were on monotherapy and 68 (27.5%; 95% CI: 22.3%, 33.5%) on polytherapy. For those on polytherapy, there were 58 (85.3%, 95% CI: 74.4%, 92.0%) women who had a prescription for two classes of IBD medications, while 10 (14.7% 95% CI: 8.0%, 25.6%) had greater and equal to three classes of IBD medications. The list of the combination of poly medication therapy is described in Table S2. There were 17 (6.8%; 95% CI: 4.3%, 10.8%) women with exclusive therapy using steroids, methotrexate or antibiotics during the year prior to pregnancy who were excluded from further analysis. Consequently, a total of 230 (93.1%; 95% CI: 89.2%, 95.7%) women had two consecutive prescriptions for maintenance IBD medications of biologic therapy, thiopurines or 5-aminosalicylates during the year prior to pregnancy. Of this cohort, 159 (69.1%; 95% CI: 62.8%, 74.8%) women were adherent (medication possession ratio ≥0.8) to their maintenance IBD medications during the year prior to pregnancy.

The association between medication adherence patterns with maternal and disease characteristics of women who were prescribed maintenance IBD medication one year prior to pregnancy (n = 223) and women who were adherent to maintenance IBD medications 1 year prior to pregnancy (n = 159) are described in Table 1. During the year prior to pregnancy, there was no significant difference between medication adherence pattern and maternal characteristics including maternal age (P = 0.189) and parity (P = 0.653) (Table 1). Additionally, there was no significant difference between medication adherence pattern during the year prior to pregnancy and disease characteristics including IBD subtypes (CD vs UC; P = 0.525) or class of IBD medication prescribed (biologics vs thiopurines: P = 0.946; biologics vs 5-aminosalicylates: P = 0.999) (Table 1).

Of the 159 women who were previously adherent to IBD medications during the year prior to pregnancy, 118 (74.2%; 95% CI: 66.8%, 80.5%) women were adherent, 20 (12.6%; 95% CI: 8.2%, 18.8%) women were not adherent and 21 (13.2%; 95% CI: 8.7%, 19.5%) women discontinued their IBD medication during pregnancy (Table 1). Due to small cell counts (n < 5), those who were not adherent to or discontinued their IBD medications during pregnancy were combined. No statistical differences were observed between IBD medication adherence pattern during pregnancy and maternal age (P = 0.283), parity (P = 0.893) or IBD subtypes (P = 0.515). There was, however, a significant difference between medication adherence pattern during pregnancy and class of IBD medication prescribed; a greater proportion of women who were adherent to their IBD medication during pregnancy were on biologic therapies (41.5%; 95% CI: 32.9%, 50.7%) than women on thiopurines (22.9%; 95% CI: 16.1%, 31.5%; P = 0.006). Adherence pattern was not significantly different for women on biologic therapies than women on 5-aminosalicylates (35.6%; 95% CI: 27.4%, 44.8%; P = 0.204).

Medication adherence patterns observed during each trimester are presented in Table 2. We excluded women who discontinued their IBD medication completely during pregnancy (n = 21) to observe the differences between women who were adherent and not adherent to each class of IBD medication prescribed during each trimester. In the first trimester, 48.6% (95% CI: 40.2%, 57.0%) of women were adherent to their IBD medication overall and 55.1% (95% CI: 46.6%, 63.3%) in the third trimester. There was a significant association between the medication adherence pattern and class of IBD medication in the first (biologics vs thiopurine: P = 0.014; biologics vs 5-aminosalicylates: P = 0.030) and third trimester (biologics vs thiopurines: P = 0.001; biologics vs 5-aminosalicylates: P = 0.001); where a greater proportion of women who were on biologics in the first (49.3%, 95% CI: 37.3%, 61.3%) and third trimester (56.6%; 95% CI: 45.0%, 67.5%) were adherent compared to those women on 5-aminosalicylates in the first (29.9%; 95% CI: 19.9%, 42.1%) and third trimester (26.3%; 95% CI: 17.5%, 37.6%) or thiopurines in the first (20.9%; 95% CI: 12.6%, 32.6%) and third trimester (17.1%; 95% CI: 10.1%, 27.6%). In the second trimester, 31.2% (95% CI: 23.9%, 39.5%) were adherent to their IBD medications overall and adherence pattern did not significantly differ by drug class (biologics vs thiopurines P = 0.348; biologics vs 5-aminosalicylates P = 0.999). There were 39.5% (95% CI: 24.7%, 55.3%) of women on biologics who were adherent in the second trimester, 41.9% (95% CI: 27.7%, 57.5%) on 5-aminosalicylates and 18.6% (95% CI: 9.3%, 33.7%) on thiopurines.

There was no significant risk of preterm birth or extended length of stay for infants born to women with IBD who were adherent and not adherent to their maintenance medication (Table 3). However, infants born to women with IBD who were adherent to their maintenance IBD medication had 1.58 (95% 1.02, 2.27) times the risk of being admitted into a neonatal intensive care unit than infants born to the general obstetric population without IBD. A similar increased risk of being admitted into a neonatal intensive care unit was observed for infants born to women with IBD who were not adherent to medications during pregnancy (RR: 1.32, 95% CI: 0.97, 1.81), although this was not statistically significant. The increased risk of admission into the neonatal intensive care unit for infants born to women with IBD regardless of adherence to IBD medications could be explained away by an unmeasured confounder (eg, smoking, weight increase, disease activity) with a risk ratio of 2.54 or 1.97 respectively, each above and beyond the measured confounders.[21,22] Although infants born to women with IBD have an increased risk of admission into the neonatal intensive care unit than the general obstetric population without IBD, admission into the neonatal intensive care unit did not differ by adherence pattern for women with IBD (P = 0.711). The general condition responsible for the majority of the care in the neonatal intensive care unit was largely due to prematurity or low birth weight in women with IBD who were either adherent or not adherent to their maintenance IBD medication and women without IBD.

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