High prescribing physicians in our sample were the most likely to code RTIs as sinusitis while low prescribing physicians were the least likely to code sinusitis, suggesting evidence of coding bias. The extent to which this coding bias is a conscious behavior is unknown. Physicians who prescribe antibiotics at a high rate may simply be more inclined to diagnose patients with antibiotic-indicated conditions. However, we also found these physicians prescribed antibiotics at a higher rate for all RTI types.
That higher prescribers are also more likely to diagnose sinusitis was recently documented in an outpatient setting.6 While the distinction between appropriate versus inappropriate prescribing is important, studies examining variation in antibiotic use for RTIs should include all diagnoses. Excluding sinusitis (and pharyngitis) because antibiotics are sometimes warranted may inadvertently exclude most inappropriate prescribing.
Our study had some limitations. These include being conducted in the telemedicine setting, which may differ from traditional outpatient care, and our inability to account for antibiotic stewardship efforts, which may have taken place during the study period.
Physicians who prescribe a lot of antibiotics also diagnose sinusitis at a disproportionately high rate. Excluding sinusitis from studies of antibiotic overuse will therefore overlook a large share of inappropriate prescribing. Benchmarking physicians on their RTI coding in addition to antibiotic prescribing may help to mitigate coding bias.