A short course of antibiotics to eradicate Helicobacter pylori reduces the risk of peptic bleeding in people taking long-term low-dose aspirin, a UK study finds.

Previous research suggested that H. pylori might play a role in the development of peptic ulceration and ulcer bleeding in patients receiving aspirin, the study authors wrote in The Lancet, but this data was largely observational.

For this study, researchers led by the University of Nottingham recruited more than 5,000 patients aged 60 years and older, who were taking a daily dose of 325mg of aspirin or less and had tested positive for H. pylori on a breath test at screening.

Half the patients were randomised to receive a short course of antibiotics for active H.pylori eradication, involving a combination of oral clarithromycin 500mg, metronidazole 400mg, and lansoprazole 30mg twice daily for a week.

The other half followed the same regime but with an oral placebo, with researchers following both groups for a median of five years.

They found people who had received the antibiotics were 65% less likely to be admitted to hospital with ulcer bleeding over the following 2.5 years than people who had been given placebo therapy (six episodes in the active group versus 17 episodes in the placebo group).

However, this effect was lost with longer follow-up after the first 2.5 years, the researchers noted, a finding which needed further investigation.

Protection against bleeding occurred rapidly, the data showed, with the first episode of bleeding happening after six days in the placebo group, versus 525 days in the antibiotic group.

In the population studied, on average 238 people would need to be treated to avoid one hospitalisation due to peptic ulcer bleeding, they concluded.

'The establishment of H. pylori eradication as an alternative or addition to antisecretory protection adds to the gastroprotective strategies available for safe aspirin prescribing,' the study authors concluded.

'A case can be made for a test and treat approach at the time of first (aspirin) prescription, when there is probably an increased risk of peptic ulceration and gastrointestinal bleeding.'

The low rate of bleeding episodes in the trial, possibly partly linked to patients using protective treatments, and the evidence that protection against bleeding might be transient meant there was not a strong case to extend H. pylori eradication in the UK beyond patients at high risk of peptic ulcer bleeding, they added.

'Conversely, the low background of ulcer bleeding in our trial, together with availability of both H. pylori eradication and acid suppression of prophylaxis, should also inform the balance of risks and benefits of aspirin and might support a more liberal use of the drug,' they suggested.

'Such information should be factored into re-evaluations of the role of aspirin in cardiovascular disease and possible extension into the prevention of colorectal and other cancers.'