Objectives: Smartphone applications (apps) for antibiotic prescribing have been studied in observational studies. Here, we assessed whether the use of a smartphone app increased appropriate antibiotic therapy (AAT) in hospitals.

Methods: An antibiotic stewardship app (Firstline.org) was populated with local guidelines and tested in a stepped-wedged cluster randomized trial in three hospitals in the Netherlands, Sweden, and Switzerland. Defined clusters were randomized per hospital for the intervention (use of app) or standard of care. Primary outcome was AAT assessed by chart review in 15 random patients per cluster per intervention period. Secondary outcomes included clinical outcomes and user analytics. A questionnaire identifying barriers to app use was disseminated. Multivariable multilevel logistic models with time periods as fixed effects to adjust for time trend and treatment as fixed effects were employed to estimate the odds ratio of treatment.

Results: Twelve clusters in the Netherlands (1085 patients) were included, 12 in Sweden (362 patients) and 8 in Switzerland (653 patients). Overall, AAT was not increased (2.0% [95% CI, -5.92% to 9.97%]) in the intervention arm compared with control across the three centres. Mean frequency of app use by cluster was associated with an AAT increase (1.9% [95% CI, 1.18-2.62%]) across study centres; 3.2% in the Netherlands (p < 0.01), 2.8% in Switzerland (p < 0.01), and remained similar in Sweden (0.4%; p 0.46). No difference was found for the other secondary outcomes. Main barriers for app use reported in the questionnaire were easily forgetting using the app and having other tools to help prescribing antibiotics.

Discussion: Overall, the introduction of a stewardship app did not significantly increase AAT, but a prespecified secondary analysis of app use frequency was associated with a small but significant improvement of AAT. Variable uptake of the app, coexisting routes to guidelines and the impact of the COVID-19 pandemic during the trial likely had an impact on the results.

Trial registration number: ClinicalTrials.gov, trial number NCT03793946.