Reduced antibiotic prescribing did not raise serious infection rates

Thursday July 7 2016

"Surgeries that handed out the fewest pills do not have higher rates of serious illnesses," the Daily Mail reports.

A new study looked at the impact of prescribing patterns of antibiotics by GPs. The researchers were particularly interested in seeing what happened in practices where GP's did not usually prescribe antibiotics for what are known as self-limiting respiratory tract infections (RTIs).

RTIs include coughs, colds, and throat and chest infections that normally get better by themselves. Using antibiotics to treat these types of infection is not recommended as it can contribute to the growing problem of antibiotic resistance.

Researchers wanted to look at two main outcomes:

  • whether a reduction in antibiotic prescribing would lead to an increase in RTI rates
  • whether a reduction in antibiotic prescribing would lead to an increase in potentially serious RTIs, or a serious complication of an RTI, such as meningitis

Researchers assessed prescribing patterns and RTI incidence rates in more than 4 million patients across 630 GP practices in the UK. They found that reduced prescribing did not necessarily put patients at any greater risk of RTIs, or serious complications, except for a very small increase in pneumonia (0.4% yearly).

The researchers hope that findings from this study will help raise awareness about the importance to public health of only using antibiotics when necessary.

Giving a patient antibiotics for a cold or cough, just to reassure them, rather than meeting a clear clinical need, should be a thing of the past.

Where did the story come from?

The study was carried out by researchers from King's College London, the University of Southampton, University of Bristol and The Health Centre, Oxford. It was funded by the UK National Institute for Health Research Health Technology Assessment programme initiative on antimicrobial drug resistance.

The study was published in the peer-reviewed British Medical Journal (BMJ) on an open-access basis, so is free to read online.

The Daily Mail's coverage of this study was generally accurate, giving a balanced report on the study and its potential implications.

What kind of research was this?

This was a cohort study which aimed to determine whether the incidence of some diseases was higher in general practices that prescribe fewer antibiotics for self-limiting respiratory tract infections (RTIs).

Cohort studies are able to suggest a potential link between exposure and outcome but, on their own, can't confirm cause and effect. It is possible that other factors influenced the incidence of respiratory diseases observed in this study.

What did the research involve?

The researchers used data from the UK Clinical Practice Research Datalink (CPRD), which contains records from about 7% of general practices nationwide. The database is considered to be broadly representative of the UK population.

Data from 2005-2014 was analysed which allowed for a cohort of 4.5 million registered patients. The study evaluated the number of first episodes of the following respiratory tract infections:

  • pneumonia – infection of the lungs
  • empyema – pockets of pus that collect inside the body; often between the outside of lungs and the chest cavity
  • peritonsillar abscesses (quinsy) – a serious tonsil infection
  • mastoiditis – a serious ear infection
  • bacterial meningitis – a serious infection of the of the protective membranes that surround the brain and spinal cord
  • intercranial abscesses – serious infections that occur in or around the brain

The researchers also evaluated the rates of RTI consultations and antibiotic prescribing per 1,000 patients, and the proportion of RTI consultations with antibiotics prescribed. This data was used to investigate the association between antibiotic prescribing rate and antibiotic prescribing proportion with rates of infective complications.

What were the basic results?

Overall, from 2005-2014 the results showed that reductions in the rate of antibiotics prescribed were not necessarily linked to any greater risk of respiratory infection apart from pneumonia.

  • The RTI consultation rate continued in its long-term decline; it decreased from 256 to 220 per 100,000 in men and from 351 to 307 per 100,000 in women.
  • The antibiotic prescribing rate for RTIs also declined from 128 to 106 per 100,000 in men, and from 184 to 155 per 100,000 in women.
  • The proportion of RTI consultations with antibiotics prescribed declined from 53.9% to 50.5% in men, and from 54.5% to 51.5% in women.
  • Over the same period, declining rates of incidence were observed for peritonsillar abscesses (1% yearly), mastoiditis (4.6%) and meningitis (5.3%).
  • Pneumonia showed an increase of 0.4% yearly, and no clear change was observed for empyema and intracranial abscesses.

How did the researchers interpret the results?

The researchers concluded: "Antibiotic prescribing for RTIs might expect a slight increase in the incidence of treatable pneumonia and peritonsillar abscess. No increase is likely in mastoiditis, empyema, bacterial meningitis, intracranial abscess, or Lemierre's syndrome.

"Even a substantial reduction in antibiotic prescribing was predicted to be associated with only a small increase in numbers of cases observed overall, but caution might be required in subgroups at higher risk of pneumonia."

Conclusion

This cohort study aimed to determine whether the incidence of some diseases was higher in general practices that prescribe fewer antibiotics for self-limiting respiratory tract infections (RTIs).

It found that alongside reductions in the rate of antibiotics prescribed, rates of incidence for peritonsillar abscesses, mastoiditis and meningitis declined. Pneumonia showed a slight increase and no clear change was observed for empyema and intracranial abscesses.

The study had a good sample size, and represented the UK population well in terms of age and sex. However, there are a few points to note:

  • As the researchers acknowledged, the study observed outcomes from a population perspective and therefore was unable to deal with variations in prescription at the individual doctor or patient level.
  • This study only looked at data collected from GP surgeries, and prescription and infection incidence rates may be higher in emergency departments or out-of-hours practices which this study was not able to capture.
  • Finally, due to its study design, these findings can't confirm cause and effect. It is possible that unmeasured confounders influenced the reported associations.

The researchers hope these findings will potentially be used in the context of wider communication strategies to promote and support the appropriate use of antibiotics by GPs.

Patients can also help by not pressuring GPs for antibiotics "just in case" they may need them.

Read more about how we can all help combat the threat of antibiotic resistance.

Analysis by Bazian
Edited by NHS Choices