The most widely prescribed type of drug for heartburn may also increase the risk of heart attack significantly. Photo by PrinceOfLove/Shutterstock
STANFORD, Calif., June 10 (UPI) -- Proton-pump inhibitors, or PPIs, are among the world's most widely prescribed drugs and help tens of millions of people deal with heartburn. But they may also significantly increase the risk for heart attack, according to a new study of medical records.
Researchers found that the second most prescribed type of drug for heartburn, H2 blockers, did not increase patients' risk for heart attack, highlighting the difference in the way the drugs work, researchers said.
"The association we found with PPI use and increased chances of a subsequent heart attack doesn't in and of itself prove causation," lead author Nigam Shah, an assistant professor of biomedical informatics and assistant director of the Stanford Center for Biomedical Informatics Research, said in a press release.
Nearly 3 million health records were reviewed for heartburn treatment, with roughly 300,000 patients' records qualifying. The rate of heart attack among patients taking PPIs was compared to the rate among heartburn patients not taking PPIs, revealing a 16 to 21 percent increased chance of heart attack among those using PPIs.
Previous Stanford research has shown that PPIs diminish the level of nitric oxide in endothelial tissue, which Shah said means anybody using the drugs could be more susceptible to heart attack.
"We looked at cardiovascular risk for different PPI drugs," Shah said. "And we found that the degree to which the use of any particular PPI was associated with a subsequent heart attack mirrors the degree to which the drug inhibits nitric oxide in the vasculature."
About 20 million Americans each year use PPIs such as omeprazole, marketed as Prilosec, for acid reflux, filling about 100 million prescriptions, and many PPIs are now available over the counter.
The authors caution people with heartburn not to simply stop taking their PPIs because more research is needed into both PPIs' and H2 blockers' effect on the vascular system.
"This association needs to be tested in a large, prospective, randomized trial," said Dr. Nicholas Leeper, the study's senior author and an assistant professor of vascular surgery and of cardiovascular medicine. "The truth will come out when we randomize several hundred people, give half of them PPIs and put the other half on H2 blockers and see what happens."
The study is published in PLOS ONE.