Over-Long Antibiotics Courses 'May Fuel Resistance'

Liam Davenport

February 28, 2019

Many antibiotics are prescribed for longer than guidelines would recommend, potentially increasing the risk of antibiotic resistance, say UK researchers in findings that suggest there is substantial scope for improved prescribing.

A team led by Koen Pouwels of the Modelling and Economics Unit at the National Infection Service of Public Health England, looked at more than 930,000 consultations in England for 13 common infections over a 2-year period.

They found that, for respiratory infections and otitis media, at least 80% of antibiotic prescriptions exceeded the recommended duration. The figures were lower for conditions that required longer antibiotic courses.

Poor Guideline Adherence

The research, published by the BMJ on 27th February, revealed that, overall, antibiotic courses lasted a total of 1.3 million days longer than their recommended duration.

The team writes that, while previous research has shown that antibiotic overuse can be reduced by limiting unnecessary prescriptions, their findings show that it "may also be substantially reduced by aligning the course length more with guidelines and best available evidence".

Koen Pouwels told Medscape News UK that poor guideline adherence may result from a number of factors.

"This may include lack of awareness and scepticism of specific guideline recommendations," he said.

He emphasised the importance of primary care doctors being aware of the recently published National Institute for Health and Care Excellence (NICE) antimicrobial prescribing guidelines.

"These guidelines are based on the best available evidence, which increasingly indicates that shorter durations than previously recommended are safe and effective to use."

Koen Pouwels continued: "Another factor that may play a role, and has been observed to play a role in certain hospital settings, is that software will automatically suggest a longer duration than necessary when prescribing certain antibiotics."

He also pointed out that the number of pills per package "could influence treatment decisions".

"However, both are system factors that could be addressed to help prescribers make more patient tailored decisions about the minimum effective treatment duration."

GPs Under Pressure

Dr Helen Stokes-Lampard, chair of the Royal College of General Practitioners, said in a statement that general practitioners "are in an incredibly difficult position when it comes to antibiotics prescribing.

"We are under huge pressure not to prescribe, and publicly vilified when we are deemed to do so too readily, yet we know that in some cases antibiotics are a matter of life or death."

She said: "Getting the balance right every time is extremely challenging."

Dr Stokes-Lampard emphasised that GPs are doing "an excellent job" in reducing antibiotic prescribing "but our priority will always be the patient in our consultation room, and we will prescribe based on the unique combination of factors potentially affecting that patient's health at that time".

Acknowledging the need to curb antibiotic resistance, she nevertheless added: "antibiotics are also important, life-saving drugs and it's vital that doctors are not deterred from using them when they think it's appropriate to do so."

Overuse of Antibiotics

The researchers point out that the overuse of antibiotics increases the risk not only of antibiotic resistance but also adverse effects such as diarrhoea, rash, and candidiasis, as well as, more seriously, Clostridium difficile infection.

While studies examining overuse of antibiotics in primary care have traditionally looked at the initial prescribing decision, relatively little attention has been paid to the length of treatment.

It is suggested that courses be long enough to treat the target bacteria, but "current concerns primarily relate to the development of resistance in common commensal bacteria, rather than in the ones causing the infections," the researchers write.

To look at this issue further, they gathered data from The Health Improvement Network, a primary care electronic database of representative general practice consultations. They looked at data on oral antibiotic prescribing in 2013–2015 for acute sinusitis, acute sore throat, acute cough and bronchitis, pneumonia, acute exacerbation of chronic obstructive pulmonary disease (COPD), acute otitis media, acute cystitis, acute prostatitis, pyelonephritis, cellulitis, impetigo, scarlet fever, and gastroenteritis.

The team identified 931,015 primary care consultations that led to antibiotic prescriptions for the included infections. This covered approximately 20% of all antibiotics prescribed in England during the study period.

The most common indications were acute cough and bronchitis, in 41.6% of consultations, acute sore throat, in 25.7%, and acute otitis media, in 8.9%, acute sinusitis in 8.2%, followed by cellulitis in 5.9%, and acute cystitis in 5.7%.

Comparing the duration of antibiotic treatment with Public Health England recommendations, the team found that there was poor guideline adherence for several of the included indications.

Overall, antibiotics were prescribed for 1.3 million days beyond their recommended duration, which remained constant over the study period.

The excess was largely accounted for by respiratory infections and otitis media, where at least 80% of treatment courses exceeded the guideline recommendations.

Although fewer prescriptions exceeded the recommended duration for non-respiratory infections, 54.6% of prescriptions for acute cystitis in women, for example, were longer than the guidelines recommendations.

Exceptions to this were acute sinusitis, for which only 9.6% of courses exceeded recommended durations, and conditions that require longer durations of treatment, such as pneumonia.

The researchers found that the median number of days of antibiotic prescription over the recommended duration was 2 for acute cough and bronchitis and otitis media, 3 for acute sinusitis, and 7 for cellulitis.

For acute cystitis, antibiotics were overprescribed for 4 days in women and 7 days in men.

"In general, the tendency was to write prescriptions with a duration of 5 or 7 days or multiples thereof," the team said.

"The peak at 7 days, however, tended to be higher than for 5 days, even for conditions where a duration of 5 days is recommended."

There was a suggestion in the data that younger patients with acute cough and bronchitis, acute otitis media, impetigo, pyelonephritis and gastroenteritis were more likely to be given prescriptions exceeding recommended treatment durations than their older counterparts.

The results also showed that, in some cases, there was substantial underuse of antibiotics.

In male patients with acute prostatitis, 52.3% of patients had antibiotic courses below the recommended 28-day course, while 31.8% of men with acute cystitis were not treated for the recommended 7 days.

There was also evidence of underuse when prescribing trimethoprim for pyelonephritis, antibiotics in general for impetigo, and penicillin V for scarlet fever.

Implications for Practice

In an accompanying editorial, Prof Alastair Hay, Centre for Academic Primary Care, Bristol Medical School, and Population Health Sciences, University of Bristol, writes that there are implications for practice from the findings.

He underlines that prescribers "cannot be held responsible for what they were doing before new guidelines were issued, but we can familiarise ourselves with the latest NICE guidance and optimise practice from here on".

Prof Hay notes: "Both clinicians and patients may need convincing to abandon longer courses of antibiotics."

He adds: "Future campaigns by Public Health England to 'Keep Antibiotics Working' could usefully emphasise that when antibiotics are needed, shorter courses are sufficient to kill bacteria and less harmful than longer courses."

Prof Hay also notes that patients should be told to expect that some symptoms do "persist beyond the end of the course, in some cases up to 4 weeks".

Koen Pouwels said that the researchers are already conducting a follow-up study to evaluate "whether there are certain types of prescribers that are more frequently prescribing longer antibiotic courses than necessary.

"This work will be complemented by interviews to better understand the reasons why prescribers are deviating from guideline recommendations."

He added: "The results of that work could potentially be used to develop interventions and support tools that could increase adherence to guidelines and reduce unnecessary antibiotic use."

The authors are supported by the National Institute for Health Research Health Protection Research Unit in Healthcare Associated Infections and Antimicrobial Resistance at the University of Oxford in partnership with Public Health England. Ann Sarah Walker is also supported by the NIHR Oxford Biomedical Research Centre.

No conflicts of interest declared.

Hay is a member of the NICE managing common infections guideline committee.

BMJ 2019; 364: l440 doi: 10.1136/bmj.l440
BMJ 2019; 364: l780 doi: 10.1136/bmj.l780

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