UK study deems 20% of primary care antibiotics inappropriate

At least 20% of all antibiotics prescribed in UK primary care could be classified as inappropriate, according to new research published by Public Health England (PHE).

The research appears in a study published yesterday in a special supplement of the Journal of Antimicrobial Chemotherapy, along with four other studies on the appropriateness of antibiotic prescribing in English primary care. Those studies found that more than two thirds of antibiotic prescriptions were linked to conditions of the respiratory tract and urinary tract infections, but in a third of all prescriptions no clinical justification was documented.

Respiratory conditions, including sore throat, cough, sinusitis, and ear infection, had the most inappropriate prescriptions.

While the amount of inappropriate prescribing varied widely, all practices included in the analysis were found to prescribe antibiotics when they weren't necessary. The authors of the study say this suggests that all practices in England have the potential to reduce antibiotic prescribing without withholding antibiotics for those patients who truly need them.

In 2016, the British government called for cutting the amount of inappropriate antibiotic prescribing by general practitioners (GPs) in half by 2020. The authors say that, to meet that goal, they first needed to quantify the extent of the problem.

A similar study was conducted in 2016 by the US Centers for Disease Control and Prevention with the same purpose. That study found that approximately 30% of all oral antibiotics prescribed in US outpatient settings are inappropriate.

Based on the findings of the new study, total antibiotic prescribing in English primary care would need to be reduced by 10% to meet the UK government's goal, PHE officials say.      

"This publication highlights the role GPs can play, and I urge all practices to look at ways they can reduce their inappropriate prescribing levels to help make sure the antibiotics that save lives today can save lives tomorrow," PHE medical director Paul Cosford, MB BS, said in a PHE press release.

Identifying inappropriate prescribing

For the study, PHE researchers analyzed antibiotic prescribing data from 2013 through 2015 recorded in The Health Improvement Network (THIN), a primary care electronic database that contains the electronic medical records of more than 11 million UK patients. They identified inappropriate prescribing events by comparing prescriptions against treatment guidelines, comparing the actual proportions of GP consultations that resulted in a prescription with the ideal proportions derived from expert opinion, and identifying high prescribers and variations in prescribing practices.

The researchers then used three different levels of estimates for inappropriate prescribing. The most conservative scenario was based on the most generous estimates of antibiotic appropriateness from the experts, while the least conservative scenario was based on the strictest estimates of the experts. A middle scenario split the difference.

Overall, data on more than 3.7 million prescriptions from 260 (74.5%) out of 349 English primary care practices that contributed to THIN during the study period were included for analysis. Only 22.6% of these prescriptions could be identified as appropriate or inappropriate; others couldn't be analyzed because they were not covered by guidelines or there wasn't enough information about the patients or their symptoms. More than 33% couldn't be assessed because they lacked an informative diagnostic code.

Under the most conservative scenario, 8.8% of all antibiotic prescriptions during the study period were classified as inappropriate. Under the least conservative scenario, 23.1% of prescriptions were considered inappropriate, and 15.4% were considered inappropriate under the middle scenario.

In addition, inappropriate prescribing was identified in all included practices, ranging from a minimum of 3.6% of a practice's prescriptions in the most conservative scenario to as high as 52.9% in the least conservative scenario. No relationship between the practices' antibiotic prescribing rates and their proportions of inappropriate prescriptions was found.

Unsurprisingly, the conditions found to contribute most to inappropriate prescribing were respiratory illnesses, which are typically caused by viruses but are frequently targets of unnecessary prescribing. In the middle scenario, these conditions included sore throat (23% of all identified inappropriate prescriptions), cough (22.2%), sinusitis (7.6%), and acute otitis media in patients between 6 months and 18 years old (5.7%). These rankings remained the same in the other scenarios.

In another analysis in the supplement that looked at antibiotic consultations, the researchers found that most primary care practices in England prescribe considerably more antibiotics for several selected conditions than would be expected based on guidelines and expert opinion. For example, an antibiotic was prescribed in 41% of all acute cough consultations, when the "ideal" prescribing rate for that condition would be 10%. The difference between actual and ideal prescribing was even more pronounced for rhinosinusitis (82% vs. 11%), acute otitis media (88% vs. 17%), acute bronchitis (82% vs. 13%), and acute sore throat (59% vs. 13%).

Even though only 22% of the prescriptions could be classified as appropriate or inappropriate, the authors of the study say their research indicates the existence of "substantial inappropriate antibiotic prescribing" and the potential for reductions. "The real reduction potential is probably higher, and it is important to note that the totality of inappropriate prescribing is a moving target that may change with better data, new specific insights, and novel diagnostic tools becoming available," they write.

Improved documentation, better diagnostic tools

In an accompanying commentary, Dame Sally Davies, the chief medical officer for England, noted that the findings were discussed at a joint PHE/Department of Health workshop and that a consensus was reached that at least 20% of antibiotic prescriptions in English primary care are currently inappropriate. But she thinks that estimate is likely conservative, and she says the PHE analysis indicates that efforts to reduce inappropriate prescribing should be made throughout primary care.

Efforts to pick some of the low-hanging fruit have already begun. In January, PHE and the National Institute for Health and Care Excellence (NICE) issued new guidance advising against the use of antibiotics in most cases of acute sore throat.

Davies would also like to see England aim higher than a 10% reduction in primary care antibiotic prescribing. By comparison, Belgium is aiming to reduce the number of antibiotic prescriptions by at least 25% by 2020, while the Netherlands is aiming for a 45% reduction by 2020.

"As microorganisms do not respect borders, we can only tackle this if every country and sector plays its part in full," Davies writes.

Achieving those kind of reductions in England, Davies says, will require improved documentation for why antibiotics are being prescribed, along with reliable point-of-care tests and diagnostic tools that can help clinicians identify those who are most likely to benefit from the drugs.

See also:

Feb 27 J Antimicrob Chemother supplement

Feb 27 J Antimicrob Chemother commentary

Feb 27 PHE press release

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