Background: Respiratory tract infection (RTI) is the leading reason for avoidable antimicrobial use in primary care, yet provider-level feedback on its use is only available in some provinces. The aim of this study was to validate case definitions for RTI across the Canadian Primary Care Sentinel Surveillance Network (CPCSSN) and determine baseline provider-level variability in antimicrobial prescribing in 2019.
Methods: The RTI case definitions were developed using demographic, diagnostic coding and keywords in electronic medical record. Manual chart abstraction was performed to identify cases of acute otitis media. Remaining RTI definitions were validated using a random sample of 5,164 patients with encounters in 2019. The proportion of patients with an RTI treated with antibiotics was determined by provider, per patient, per episode and per patient encounter.
Results: Negative predictive value, positive predictive value and prevalence were as follows: 1.00 (0.99-1.00), 0.99 (0.96-0.99) and 4.14% (4.10-4.19) for common cold; 1.00 (0.99-1.00), 0.94 (0.88-0.98) and 1.09% (1.07-1.12) for acute otitis media; 0.98 (0.96-1.00), 0.93 (0.87-0.97) and 1.2% (1.18-1.22) for acute pharyngitis; 0.99 (0.99-1.00), 0.88 (0.81-0.93) and 1.99% (1.96-2.02) for sinusitis; 0.99 (0.97-0.99), 0.95 (0.89-0.98) and 4.01% (3.97-4.05) for acute bronchitis/asthma. By provider, median (interquartile range [IQR]) proportion treated with antibiotics (per patient) was 6.72 (14.92) for common cold, 64.29 (40.00) for acute otitis media, 20.00 (38.89) for pharyngitis, 54.17 (38.09) for sinusitis, 8.33 (20.00) for acute bronchitis/asthma and 21.10 (20.56) for overall RTI.
Conclusion: The CPCSSN can provide national surveillance of antimicrobial prescribing practices for RTI across primary care. Baseline variability underscores the need for provider feedback and quality improvement.
Keywords: antimicrobial stewardship; audit and feedback; primary care; respiratory tract infection; validation.