Antibiotics prescribed by GPs in 2012 for four common infections failed in 15% of cases, according to an analysis of data in the UK Clinical Practice Research Datalink
The researchers examined nearly 11 million prescriptions for antibiotics as a first-line and single treatment for upper and lower respiratory tract infections, skin and soft tissue infections and acute otitis media. To assess treatment failure rates, they tracked further prescriptions for antibiotics issued within 30 days or looked for other markers, such as an admission to hospital with an infection-related diagnosis or referrals to infection-related specialist services.
The rate of failure of 15.4% in 2012 is an increase from 13.9% in 1991. Most of this increase occurred after 2000 when antibiotic prescribing, which had plateaued, began to rise again.
“We have shown that in primary care, where most antibiotics are prescribed, and in a developed country, the impact of increasing antibiotic treatment failure was not as great as we had anticipated based on evidence reported from hospital settings with more severe infections,” they write.
“Another interpretation of these data, however, would be that the observed rates are in reality higher because inappropriate or unnecessary prescribing could have attenuated the failure rates.”
The analysis also reveals that the rate of increase in antibiotic treatment failure was less prominent with the most commonly prescribed antibiotics and in those recommended for first-line treatment, such as broad spectrum penicillins (e.g., amoxicillin) and the macrolides (clarithromycin and erythromycin).
But there were notable increases in failure rates for certain antibiotics that are usually not recommended as first-line treatments for the four conditions, such as trimethoprim, the cephalosporins and the quinolones. “Such drugs, however, might have been prescribed for more severely ill and frail patients who had recently been prescribed a first-line drug or from whom resistant organisms had been previously isolated.”
The researchers, led by Craig Currie a professor of applied pharmacoepidemiology at Cardiff University, say they are unable to conclude whether the increased failure rate is a phenomenon that will resolve or whether it is an early indication of a more dramatic and worrying process.
“Nevertheless, the finding that treatment failure was associated with more than one in ten initial antibiotic treatments in primary care represents a considerable burden on patients and on the healthcare systems.”
The data suggest that primary care physicians can play a central role in helping to contain rises in antibiotic treatment failure, the researchers argue. This could be achieved by better managing patients’ expectations and carefully considering whether each prescription is justified.