Nov. 3 (UPI) -- A person's risk of stomach bleeding from long-term aspirin use can be reduced by taking a short course of antibiotics, which could potentially improve the safety of aspirin taken to prevent heart attacks or strokes, results of a clinical trial suggest.
Aspirin use is widespread and increasing among elderly patients, the researchers said. The main worry is gastrointestinal bleeding, whose prevalence may be increasing because of rising aspirin use.
This problem occurs because aspirin, by thinning the blood, makes ulcers in the stomach bleed. And these stomach ulcers, also known as peptic ulcers, may be caused by a particular type of bacteria: helicobacter pylori, or H. pylori.
The major clinical trial, which was conducted in the United Kingdom, was based on evidence that peptic ulcer bleeding in aspirin users occurs predominantly in H. pylori-positive people.
So, investigators looked into whether a short course of antibiotics to remove these bacteria would reduce the risk of stomach bleeding in aspirin users.
The results from the Helicobacter pylori Eradication Aspirin Trial, known as HEAT, which studied H pylori-infected individuals taking aspirin daily in England, Wales and Northern Ireland, were published Thursday in The Lancet.
Researchers described the HEAT Trial as the largest United Kingdom-based study of its kind.
"Although it seems surprising that a one-week course of antibiotics could have a prolonged effect, this is a well-recognized feature of Helicobacter pylori. It is thought that the infection is acquired during childhood and adolescence and persists thereafter. If it is eradicated during adult life, it is rare for reinfection to occur," Christopher Hawkey, a professor of gastroenterology who led the study, told UPI in an email.
Hawkey, from the University of Nottingham's School of Medicine and Nottingham Digestive Diseases Center in the United Kingdom, said the researchers retested 10% of the study's subjects and "found high levels of persistent negative status" for H. pylori.
In the United Kingdom, the peak of aspirin prescribing was in 2009 and there has been roughly a 30% decline since then due to more cautious guidelines with regard to primary prevention of cardiovascular disease and also its use in diabetics, Hawkey said.
The randomized, double-blind, placebo-controlled trial was conducted in 1,208 general medical practices in the United Kingdom. Patients were identified by their physicians, and then asked to participate in the study and take an H. pylori breath test.
Those with a positive result were randomized to receive either a short course of antibiotic treatment or placebo. No follow-up visits were required. Instead, information was gathered from the patients' electronic medical records.
Hawkey described the study as "one of the largest to be done in primary care and without funding from the pharmaceutical industry."
Active treatment for the study consisted of seven days of three oral medications: lansoprazole, 30 milligrams twice daily; clarithromycin, 500 milligrams twice daily; and metronidazole, 400 milligrams twice daily.
Hawkey described the active treatment regimen used in the study as "a standard, fairly high dose, one." The antibiotics used were all generic, not expensive, he added, noting there are a number of other regimens -- and all regimens use at least two antibiotics.
Over the first 2 1/2 years, people who received the antibiotic treatment were less likely to be admitted to the hospital because of peptic ulcer bleeding than those who received placebo tablets, the study found.
The scientists discovered that protection occurred rapidly. The first hospitalization for peptic ulcer bleeding in people who got placebo tablets occurred after six days, versus 525 days after antibiotic treatment, the release said.
Over a longer period, the protection seemed to wane, the researchers noted.
"However," Hawkey said, "rates of ulcer bleeding were very low and probably too low to warrant a test-and-treat approach in people already on aspirin. High-risk patients including those just starting aspirin would be an appropriate group for this strategy."