Delayed antibiotics for upper respiratory tract infections associated with infection-related hospital admissions
Delayed prescribing should be better targeted to patients with lower risks of complications, the study authors wrote.
Delayed antibiotic prescribing was associated with increases in the risk of infection-related hospital admissions in patients with upper respiratory tract infections (URTIs), a study found.
Researchers in the United Kingdom used primary care databases linked to hospital admission records to identify an overall source population of antibiotic users of any age who were prescribed an antibiotic for the first time in three months. The cohort was then restricted to patients who had an outpatient diagnosis either on the date of the antibiotic prescription or in the 30 days before. Patients with a URTI 30 to 90 days before were excluded to ensure acute URTI at the date of the antibiotic prescription. The cohort was further narrowed to patients prescribed the most common antibiotics: amoxicillin, clarithromycin, doxycycline, erythromycin, or phenoxymethyl penicillin.
Patients were stratified by delayed and immediate antibiotic prescribing relative to a URTI diagnosis. The study's primary outcome was hospital admission for infection-related complications occurring in the 30 days after the antibiotic prescription, excluding the date of the antibiotic prescription. Results were published June 29 by Clinical Infectious Diseases.
The cohort included 1.82 million patients with URTI and antibiotic prescription. Overall, 91.7% were prescribed an antibiotic at URTI diagnosis date (immediate) and 8.3% had received a URTI diagnosis in the one to 30 days before receiving an antibiotic prescription (delayed). Delayed antibiotic prescribing was associated with a 52% increased risk of infection-related hospital admissions (adjusted hazard ratio, 1.52; 95% CI, 1.43 to 1.62). The probability of delayed antibiotic prescribing was unrelated to predicted risks of hospital admission.
Analyses of number needed to harm (NNH) with delayed antibiotic prescribing showed considerable variability across different patient groups. The median NNH with delays in antibiotic prescribing was 1,357 (2.5th percentile, 295; 97.5th percentile, 3,366). Patients with higher predicted risks of hospital admission were in general as likely to receive a delayed antibiotic prescription as patients with very low risks, and no substantial changes were seen over time.
Among the study limitations, patients were not randomized to different antibiotic strategies. The observed increase in the risk of clinical outcomes with delayed antibiotic prescribing could be related to more severe infection or to underlying differences in patient characteristics, and more severe infections in patients with delayed antibiotic prescribing could causally explain the findings, the authors noted.
“There is an important need to better target delayed antibiotic prescribing to URTI patients with moderate risks of complications and immediate antibiotic to those with higher risks,” they wrote. “Further research on the cost-effectiveness of the most optimal threshold is needed to establish the treatment thresholds.”