Primary care pharyngotonsillitis complications following absent or deferred antibiotic treatment across the COVID 19 pandemic

BACKGROUND: Antibiotic prescribing for pharyngotonsillitis in primary healthcare significantly influences patient outcomes, particularly concerning the risk of complications. This study examines trends in antibiotic use and the associated risk of complications before, during and after the pandemic. METHODS: This study used large-scale, register-based data linking primary healthcare records with national and regional registers. The study included individuals aged 12 and older from the Stockholm and Västra Götaland regions, representing about 40% of the Swedish population. We identified 295,972 cases of pharyngotonsillitis between 1 January 2018 and 30 December 30, 2023, applying a 180-day washout period to ensure distinct episodes. Logistic regression models estimated adjusted odds ratios (aORs) with 95% confidence intervals (CIs) for complications within 30 days, comparing patients who received antibiotics to those who did not. RESULTS: Antibiotic prescriptions temporarily decrease during the pandemic, followed by a partial rebound, with penicillin remaining the preferred antibiotic. Complications, with peritonsillar abscess being the most common, were more frequent in patients receiving antibiotics (1.75%) compared to untreated individuals (0.43%). Among treated patients, those prescribed penicillin had fewer complications (1.62%) than those given other antibiotics (2.87%). After adjusting for sociodemographics, comorbidities, primary care visits, and vaccination status, the risk for complications is lower for untreated patients (aOR 0.24, 95% CI 0.22-0.26). CONCLUSIONS: The COVID-19 pandemic impacted antibiotic prescribing patterns in Swedish primary care, with a substantial reduction in overall antibiotic prescribing during the pandemic. Penicillin's continued use as a first-line therapy appears well-justified, given its lower associated risk of complications.