Simple blood test reduces antibiotic use in patients with acute respiratory infections

Professor Yahya Shehabi from Monash University.

A simple blood test that returns results to doctors within twenty minutes will enable them to accurately prescribe the most appropriate type and dose of antibiotics, potentially saving lives and significantly improving patient outcomes.

Patients with acute respiratory infections should be tested for a blood marker for bacterial infection to determine antibiotic treatment, according to the large international study including research at Monash University.

Published last week in The Lancet, the systematic review analysed data from 32 randomised controlled trials across 12 countries to investigate the use of procalcitonin—a biomarker for bacterial infections—as a tool to improve decisions about antibiotic therapy.

Acute respiratory infections (ARIs) comprise a large groups of infections including bacterial, viral and from other causes, accounting for more than 10 per cent of global disease burden, and are the most common reason for antibiotic therapy.

“As many as 75 per cent of all antibiotic doses are prescribed for ARIs, despite their mainly viral cause,” said co-author Professor Yahya Shehabi from Monash University, who is also Director of Research, Critical Care and Perioperative Medicine at Monash Health.

“In people with acute respiratory infections, unnecessary antibiotic use significantly contributes to increasing bacterial resistance, medical costs, and the risk of drug-related adverse events.”

The blood marker procalcitonin (PCT) increases in bacterial infections and decreases when patients recover from the infection.

“Our review shows for the first time that PCT supports clinical decision-making about initiation and discontinuation of antibiotic therapy,” said Professor Shehabi, the only Australian author on the study.

“We can do a simple blood test at the patient’s bedside, and within twenty minutes, we will know the patient’s PCT levels and can accurately determine the type and dose of antibiotic we should give to best treat the patient.

“Currently, many patients receive antibiotics who don’t need them, and we’re also not always giving the most appropriate type or dose of antibiotics to those patients who do need them.

“Testing for PCT enables doctors to accurately prescribe the correct type of antibiotic, as well as when to start, stop or change therapy.

“This brings us a step closer to personalised medicine—individualised patient therapy.”

The meta-analysis using data from 6708 patients showed that the use of PCT to guide initiation and duration of antibiotic treatment results in lower risks of mortality, lower antibiotic consumption and lower risk for antibiotic-related side effects.

The study results were similar for different clinical settings and types of ARIs, supporting the use of PCT when determining antibiotic therapy in people with ARIs.

Professor Shehabi said study participants in the PCT-guided group had a 2.4 day reduction in antibiotic exposure and a reduction in antibiotic-related side effects (16.3 per cent versus 22.1 per cent).

“We’ve shown through this study there’s almost a 17 per cent reduction in the odds of dying if treatment is guided by PCT, as a result of reduced and unnecessary antibiotics exposure, and more appropriate antibiotic treatment,” Professor Shehabi said.

Professor Shehabi said the new test will contribute to a dramatic cost saving to hospitals—approximately 30 per cent due to reduced drug use and improved patient monitoring.