LESS than 20% of doctors starting their patients on low dose aspirin consider testing for the presence of Helicobacter pylori infection, but a new meta-analysis showing a doubled risk of bleeding may convince them otherwise.

Guidelines from the United States and Europe currently recommend that patients who are about to start on low dose aspirin for cardiac health be tested for H. pylori and treated, if necessary, before beginning an aspirin regimen, but both guidelines come with the caveat the evidence base for that recommendation was “weak”.

However, the meta-analysis published in the MJA has strengthened that evidence base with a finding that, if patients who take low dose aspirin also have H. pylori infection, they have roughly double the chances of having an upper gastrointestinal (UGI) bleed.

Dr Justin Ng, a resident at Peninsula Health south of Melbourne, told MJA InSight in an exclusive podcast that previous evidence on the interaction between aspirin and H. pylori was “indirect and conflicting”, prompting him to investigate further.

“The [recommendation] was based on a meta-analysis that looked at patients taking conventional non-steroidal anti-inflammatory drugs (NSAIDs) instead of aspirin,” said Dr Ng.

“They both inhibit the enzyme cyclooxygenase-1, which lowers the prostaglandin production in the stomach lining, and makes it prone to ulcers and bleeding. But low dose aspirin also causes UGI bleeding by stopping the platelets from aggregating, which would otherwise stop an ulcer from bleeding.

“Because the meta-analysis looked at conventional NSAIDs, you can’t directly apply it to aspirin because of that extra mechanism.

“That’s indirect evidence.”

Dr Ng said three other studies found low incidence of reoccurrence of UGI bleeding in H. pylori-positive aspirin users after the eradication of the infection; another showed that the reoccurrence of UGI bleeding in low dose aspirin users at 12 months after eradication [of the H. pylori infection] was as high as 15%; and a third showed no difference between eradicating H. pylori or just leaving it there and putting the patient on a proton-pump inhibitor (PPI).

“The evidence wasn’t very clear, so that’s why we took another look at it.”

Should every patient about to start low dose aspirin therefore be tested for the presence of H. pylori infection?

“That’s a very straightforward question but the answer is not as straightforward,” said Dr Ng.

“The current guidelines already recommend that we should be testing everyone about to start low dose aspirin for H. pylori … [and] our meta-analysis provides more robust evidence to support that recommendation.

“We calculated the numbers needed to treat H. pylori as being somewhere between 150 to 1500 patients before you can prevent one extra bleed per year.

“That number is quite large, so we don’t think applying a blanket rule would be [a good idea]. It takes a lot of time to treat H. pylori – it’s a prolonged course of antibiotics and PPIs. There needs to be testing before and after to make sure eradication successful.

“It’s a high burden for patients and for GPs.”

Dr Ng said there were no published data about how often doctors were testing patients for H. pylori before starting them on low dose aspirin; however, for conventional NSAIDs, the data suggested that less than 20% of doctors did so.

“Anecdotally, some of our cardiology colleagues have told us that they never think about H. pylori before they start on low dose aspirin.

“Even neurologists with patients who have had a stroke and need to start on low dose aspirin – H. pylori doesn’t necessarily come to mind, which is understandable,” he said.

Patient selection, he said, was key.

“Anyone with high risk of developing peptic ulcers in general should be tested and treated for H. pylori,” said Dr Ng. “We know that the risk factors are taking a conventional NSAID, a past history of UGI bleeding, smoking, and increasing age.

“So, it’s a case of picking the right patient.”

 

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