MD,Phd , Assoc. professor Bispebjerg and Frederiksberg Hospital Bispebjerg, Denmark
Background: Since the 90´s immunomodulatory treatment against multiple sclerosis has been available, and clinicians often have to advice pregnant women on the therapeutic benefits versus fetal risks
Objectives: To investigate whether exposure to interferon-beta in utero affected the risk of acquiring infections during childhood.
Methods: Retrospective matched cohort. Through the Danish Multiple Sclerosis Registry, we identified all children born to mothers with MS in Denmark during the period 1998 to 2018. The study included 510 children exposed to interferon-beta in utero. To avoid confounding from secular trends or social and regional differences we performed our analysis on a matched dataset. Matching was performed with the greedy nearest neighbor matching algorithm (calliper width 0.1 on the propensity score scale) without replacement. The cohorts were matched on the following variables: year of birth , gender, region of birth, mother´s age at delivery and educational level. Standardized mean differences (SMDs) were computed to assess the balance in the matched cohort with 10% considered as an acceptable difference. The children were matched 1:1 with children born to mothers with untreated MS and 1:3 with children born to mothers without MS. Each child was followed for up to five years. Using individual-level data, we investigated all-cause mortality, rate of hospital admissions due to infections, and redeemed prescriptions of antibiotics. The primary statistical model applied was a negative binomial regression analysis.
Results: : There were no differences in childhood mortality. Overall, the rates for hospital admissions and dispensed antibiotic prescriptions were lower among children exposed to interferon-beta in utero than in the two other groups but did not reach the threshold for statistical significance, the rate ratio compared to healthy controls was for hospital admissions was 0.79 (0.62-1.00). Regarding antibiotic prescriptions, the results were similar (RR 1.00 (0.90-1.11). Furthermore, we found no certain dose-response relationship between IFN-β exposure duration and hospital admission rate (P=0.47) or redeemed antibiotic prescription (P=0.71).
Conclusions: These data suggests that exposure to interferon-beta has no or limited impact on the risk of acquiring infections during childhood.
