Prevalence of unnecessary antibiotic use in European hospitals – a systematic review

Abstract Background Antibiotics (AB) are essential to modern day medicine as prophylaxis and therapy. Yet, unnecessary use has various negative effects on individual and global health, such as antimicrobial resistance (AMR) and contribution to high greenhouse gas (GHG) emissions of the healthcare sector. This systematic review provides an overview of unnecessary AB use in European hospitals in order to present possible ways forward. Methods The systematic review followed PRISMA guidelines, included as databases were: Embase, ProQuest Environmental Science Collection, PubMed, ScienceDirect, Scopus and Web of Science. Studies conducted among adult in-patients in EU/EEA countries were included if they provided assessment methodology, included a clear standard of measurement and chart reviews were used as evaluation basis. Results Fifty-six included studies were categorised into the following three groups: (1) Studies using an established evaluation method; 20 studies belong to this group, 18 used the same, established approach. Eleven of these studies performed an observational audit, while the interventions in the remaining studies were of educational or advisory nature. Unnecessary AB use ranged from 1.5% to 51% of all observed prescriptions. Outcomes of interventions showed great variation of effects on unnecessary use (-34.7% - +11.6). (2) Studies using a newly developed, clearly stated evaluation method (4 studies); (3) Studies which conform with established evaluation methods but the processes were not specified (32 studies). Results are subject to further analysis. Conclusions The studies included reported a great range of unnecessary AB use in adult in-patients, for both prophylactic and therapeutic indications. Evaluation methods of unnecessary AB use vary greatly between studies. In future research, comprehensive application of established approaches is essential for better overview and identification of key areas for AMR and GHG emission reduction activities. Key messages • Unnecessary antibiotic use varies greatly among studies conducted in European adult in-patients. • In future research, wider application of established evaluation methods will improve comparability and targeting of interventions.