Reduced outpatient antibiotic prescribing is not associated with increased incidence of upper respiratory tract infections and complications: a large population-based cohort study.

OBJECTIVES: Inappropriate antibiotic use contributes to adverse events and resistance development. Implementation of antimicrobial stewardship (AMS) programmes has resulted in marked declines in outpatient antibiotic prescribing in several countries (e.g., Canada, Sweden). Upper respiratory tract infections (URTIs) are important targets for AMS interventions, because they are the most common indication for outpatient prescribing and are frequently overtreated. However, limited data exist to support that the reductions in antibiotic use are safe, with respect to the incidence of primary infections and complications. This study aimed to safeguard that the observed declining trends in outpatient prescribing were not associated with clinically relevant increasing trends in URTIs, in a large Swedish cohort. METHODS: In this population-based register study, we extracted data recorded in the Stockholm Regional Data Warehouse (VAL) from 2014 to 2023. VAL encompasses primary care, outpatient secondary care, and inpatient care for all residents of the Stockholm healthcare region, and includes ICD-10 diagnoses, consultation dates, hospital admissions, and pharmacy antibiotic dispensations. We first analysed trends in antibiotic prescriptions (per 1,000 inhabitants/year), primary URTIs (diagnoses, episodes, patients per 10,000 inhabitants/year) and complications. We then linked primary infection episodes to subsequent infectious complications, stratified by antibiotic treatment. RESULTS: Analyses revealed sustained reductions in antibiotic prescriptions and URTIs, and low complication rates. Peritonsillitis was most frequently recorded (4.48-7.67 cases per 10,000 inhabitants/year), while other complications generally occurred at rates below 1 case per 10,000 inhabitants/year. The incidence of meningitis and ethmoiditis declined, whereas mastoiditis showed a modest annual increase (average 0.031 cases per 10,000 inhabitants). CONCLUSIONS: Despite significant reductions in antibiotic prescribing over the 10-year study period, we found a decline in primary URTI episodes and low rates of complications. These findings support the safety of current prescribing levels and clinical practice guidelines for URTIs, as well as ongoing national AMS programmes.