Antibiotic Utilization Among People With Multiple Sclerosis in the Netherlands, 2018-2020

Purpose: The purpose of this study was to describe the intensity and patterns of antibiotic drug use among people with multiple sclerosis (pwMS) in the Netherlands.

Methods: People with prevalent MS between 1 January 2018 and 31 December 2020 were identified using ambulatory hospital records from the PHARMO Database Network that contains routinely collected healthcare data from the Netherlands. Out-patient pharmacy dispensing data were used to assess type of antibiotic, dosage, and amounts dispensed. Antibiotic intensity in defined daily doses (DDD)/1000 patient-days (PD) was calculated together with frequency of dispensing of the same (prolongation) or different (switch) antibiotic up to 3 days after the end of the last antibiotic prescription; and stratified by sex, age, polypharmacy (use of > 4 out-patient prescription drugs for > 29 days), type of disease-modifying treatment, and Sars-CoV-2-related lockdown.

Results: A total of 1960 (37.8%) out of 5179 pwMS were dispensed ≥ 1 antibiotic. Of the 8762 dispensing events, 27.6%% were part of a prolongation, and 16.3% of a switch. Overall antibiotic use among pwMS was 18.8 DDD/1000 PD (95% confidence interval [95% CI]: 18.7-19.0) compared to 7.77-8.90 DDD/1000 PD in the general out-patient population, as reported by the Dutch Working Party on Antibiotic Policy. Antibiotic use was higher among women, increased with age, and was higher in people with polypharmacy and lower during lockdown. Nitrofurantoin was the most commonly dispensed antibiotic (41.7%).

Conclusions: The intensity of antibiotic use is considerably higher among pwMS than the general population. This reflects the burden of infection in this susceptible population.