Doctors are prescribing antibiotics for tens of thousands of patients with infections, with little or no consideration of prognosis and the risk of the infection worsening, according to a new study led by University of Manchester epidemiologists.

The study of 15.7 million patient records, published in the Journal of the Royal Society of Medicine today (April 4), implies there could be scope to prescribe far fewer antibiotics.

The researchers found the probability of being prescribed antibiotics for a lower respiratory tract or urinary tract infection was unrelated to hospital admission risk.

And the probability of being prescribed an antibiotic for an upper respiratory tract infection was only weakly related to hospital admission risk.

The study also showed that patient characteristics such as age and the presence of other health problems were only weakly associated with the probability of being prescribed an antibiotic for treatment of a common infection.

The most elderly patients in the sample were 31% less likely than the youngest patients to receive an antibiotic for upper respiratory infections.

That inevitably means, say the researchers, that many younger people are being prescribed antibiotics, even though they are often fit enough to recover without them, potentially leading to resistance.

Conversely, many older people—who may not be able to deal with infections without antibiotics—are not receiving them, with the potential of complications and hospital admissions.

Patients with combinations of diseases were 7% less likely than people without major health problems to receive an antibiotic for upper respiratory infections.

Lead authors are Professor Tjeerd van Staa and Dr. Ali Fahmi, from University of Manchester.

Professor van Staa said, “Antibiotics are effective in treating bacterial infections, but they carry the risks of antimicrobial resistance (AMR) and loss of effectiveness when used inappropriately.

“That is why AMR to antibiotics has been recognized as one of the biggest threats to global public health.

“Given the threat of resistance, there is a need to better target antibiotics in primary care to patients with higher risks of infection-related complications such as sepsis.

“But this study finds that antibiotics for common infections are commonly not prescribed according to complication risk and that suggests there is plenty of scope to do more to reduce antibiotic prescribing.”

The study also showed that the probability of being prescribed an antibiotic for lower respiratory infections was even more unrelated to complication risk during the pandemic; however, they were only minor changes for urinary tract infections.

The research team accessed anonymized patient-level electronic health records of primary care data from Phoenix Partnership (TPP) through OpenSAFELY, a secure platform for electronic health records in the NHS.

They included adults registered at general practices in England from January 2019 to March 2023 diagnosed with upper respiratory, lower respiratory and urinary tract infections.

Patient-specific risks of infection-related hospital admission were estimated for each infection using risk prediction scores for patients who were not prescribed an antibiotic.

Dr. Ali Fahmi added, “Rather than imposing targets for reducing inappropriate prescribing, we argue that it is far more viable for clinicians to focus on improving risk-based antibiotic prescribing for infections that are less severe and typically self-limiting.

“Prognosis and harm should explicitly be considered in treatment guidelines, alongside better personalized information for clinicians and patients to support shared decision making.”

“A Knowledge Support System (KSS) led by Professor Tjeerd van Staa, which provides personalized information to clinicians is now being tested in North-West England.

“We hope it could provide a workable solution to the problem of untargeted antibiotic prescribing.”