(207) Prescription of Asthma-Control Medications Dispensed During Pregnancy in Belgium: The Trends Between 2003 and 2018 Using a Medico-Administrative Database

Publication Number: 538

Background: Asthma is a common chronic condition affecting also pregnant women. It is recommended to continue the use of long-term asthma control medications during pregnancy to improve the health of mothers and the newborns. However, in Belgium there is little information about the utilization and the evolution of long-term asthma control medication during pregnancy.

Objectives: To investigate the trends in the use of long-term asthma control medications during pregnancy between 2003 and 2018 in Belgium.

Methods: We used a nationally representative database of health insurance claims, as the permanent sample. We calculated the proportion of pregnant women who filled at least one prescription of long-acting β2-agonists (ATC code R03AC12-13), inhaled corticosteroids (ATC code R03BA), combination of inhaled β2-agonists and corticosteroids (ATC code R03AK), theophylline (ATC code R03DA) and leukotriene modifiers (ATC code R03DC). The proportions were calculated for successive 2 years periods between 2003 and 2018. Logistic regressions were used to analyze the trends of the prescriptions dispensed during pregnancy while controlling for maternal age.

Results: The study included 42,582 pregnancies. Overall, we observed a significant increasing trend in the prescriptions of the asthma-control medications dispensed during pregnancy from 3% (95% CI, 2.5-3.5%) in 2003-2004 to 4.2 % (95%CI, 3.8-5%) in 2017-2018 p-trend < 0.001. A significant increase was also observed in the combination of inhaled β2-agonists with corticosteroids from 1.2% (95%CI, 0.9-1.5%) to 2.3% (95%CI, 1.9-2.8%) p-trend < 0.001. A non-significant increase was observed in the inhaled corticosteroids from 1.6% (95%CI, 1.3-1.9%) to 2.1% (95%CI, 1.7-2.6%) p-trend=0.098. The use of the three other subgroups of asthma medications was very marginal across the study periods, in the last study period (2017-2018) the proportion of pregnancies exposed to at least one prescription was 0.24% (95%CI, 0.12-0.41%) for leukotriene modifiers. For the long-acting β2-agonists alone and theophylline, the number of pregnancies exposed was less than 5.

Conclusions: Using a national database, we showed for the first time that the proportion of the pregnant women with at least one prescription of long-term asthma control medications is increasing in Belgium. The two most used medications dispensed during pregnancy were combinations of β2-agonists with inhaled corticosteroids and inhaled corticosteroids alone. The study also highlights an increase trend in the use of combination fixed-dose inhalers. While our results suggest an increasing use of asthma medication during pregnancy, future research should explore the adherence of the treatment before and during pregnancy.