A large reduction in antibiotic prescribing for respiratory tract infections (RTIs) only results in a small number of complications, such as pneumonia, new research suggests, a finding that the authors say is “reassuring”.
Following an analysis of data from 610 GP practices in the UK, researchers from King’s College London have calculated that a 10% drop in antibiotic prescriptions for RTIs would lead to one extra case of pneumonia per year at an average GP practice serving 7,000 patients.
The team also concludes the risk of other complications, such as meningitis, would not increase, apart from for peritonsillar abscess, resulting in one extra case per decade.
The researchers used data from the UK Clinical Practice Research Datalink to analyse prescribing rates for RTIs and complication rates between 2005 and 2014. In that time, prescription rates for RTI consultations dropped from 53.9% to 50.4%, while the rate of meningitis, mastoiditis and peritonsillar abscess decreased by 5.3%, 4.6%, and 1.0%, respectively. The rate of pneumonia increased by 0.4%.
The research, which was commissioned by the National Institute for Health Research as part of an initiative to study antimicrobial resistance, was carried out to determine if policies designed to reduce antibiotic prescriptions were safe. Despite the fact that RTIs are usually viral and clear up without antibiotics, concerns have been raised about whether reducing antibiotic use would lead to more complications.
In addition, some doctors have highlighted difficulty in distinguishing between conditions like flu and meningitis, which does require antibiotics. And despite a push to reduce antibiotic use for RTIs, prescribing rates remain relatively high.
Reporting their findings in The BMJ
(online, 5 July 2016), the authors found large variation in prescribing rates between GP practices. Some issued prescriptions for up to 80% of RTI consultations and others only 20%. They also found that a 10% reduction in antibiotic prescribing increased the risk of pneumonia by 12.8% (95% confidence interval [CI] 7.8%–17.5%; P<0.001) and by 9.9% for peritonsillar abscess (CI 5.6%–14.0%; P<0.001).
In an average GP practice with 7,000 people, these results translate to one extra case of treatable pneumonia per year and one extra case of peritonsillar abscess per decade, the researchers say.
Rates of mastoiditis, empyema, meningitis, intracranial abscess and Lemierre’s syndrome were not affected by prescribing rates.
Martin Gulliford, lead author of the study and a public health researcher at King’s College London, says: “The results are quite reassuring, rates of complications are not increased for many abscesses — there is a slight increase in pneumonia and peritonsillar abscess but the numbers are small.”
He adds that GP practices with higher prescribing rates “could certainly cut down on prescriptions”.
The UK has a relatively high antibiotic prescribing rate for RTIs compared with some other countries, such as the Netherlands, which has a prescribing rate of 22.5%. “We wanted to know if it’s possible to set a target for reducing prescribing for RTIs and if it’s safe to do that,” Gulliford says.
Caution might be needed in patients at higher risk of pneumonia, the researchers say, but they add that “even a large reduction in antibiotic prescribing was predicted to be associated with only a small increase in numbers of cases [of complications] observed over a 10-year period, and this would be expected to reduce the risks of antibiotic resistance, the side effects of antibiotics, and the medicalisation of largely self-limiting illnesses”.
 Gulliford M, Moore M, Little P et al. Safety of reduced antibiotic prescribing for self limiting respiratory tract infections in primary care: cohort study using electronic health records. The BMJ 2016;354:i3410. doi: 10.1136/bmj.i3410