Diagnostic Labelling, Antibiotic Appropriateness and Watch Use for Upper Respiratory Infections in Singapore Primary Care: A Multicentre Retrospective Study

OBJECTIVES: Upper respiratory infections (URIs) are commonly managed in primary care, yet diagnostic labelling and antibiotic prescribing often diverge from guidelines. We assessed URI labelling accuracy and factors influencing appropriate prescribing, and WHO AWaRe Watch versus Access selection. METHODS: We conducted a multi-centre cross-sectional study using electronic medical records from seven Singapore primary care clinics (January-April 2025). Adults aged ≥18 years with an ICD-10 code J06.9 (acute URTI, unspecified) and a same-day oral antibiotic prescription were eligible. Using stratified random sampling by clinic, we selected 518 encounters to allow for exclusions after manual review. Blinded physician reviewers verified URI criteria, if a narrower diagnosis could be assigned, and adjudicated antibiotic indication and appropriateness against guidelines. Mixed-effects logistic regression evaluated factors associated with appropriate prescribing and Watch versus Access selection. RESULTS: Of 518 encounters, 22.2% did not meet URI criteria and 24.1% could have received a narrower diagnosis. After excluding these encounters, only 4.2% of antibiotic prescriptions for URI were appropriate. Watch group antibiotics comprised 20.3%. Each additional symptom reduced odds of appropriate prescribing [Odds Ratio (OR) 0.722, 95%Confidence Interval (CI) 0.535-0.975], while eligibility for a narrower diagnosis increased it (OR 10.2, 95%CI 4.96-20.9). For Watch selection, antibiotic allergy (OR 5.77, 95%CI 2.46-13.5) and inability to assign a narrower diagnosis (OR 3.09, 95%CI 1.32-7.19) increased odds; each additional symptom decreased odds (OR 0.74, 95%CI 0.55-0.98). CONCLUSION: URI labelling was frequently inaccurate and guideline-concordant prescribing was low, supporting targeted diagnostic training and Access-first stewardship interventions.