Nearly three-quarters of heart patients surveyed in a new University of Michigan study used some kind of alternative medicine approach to help them heal, but dietary supplements chosen by one-third of them could actually interact with their heart medications to raise their risk of further health problems.

Fortunately, the vast majority of those who used alternative medicine techniques told their doctors about it, and also kept up with their prescription medications. The findings, which were presented at the American College of Cardiology's 51st Annual Scientific Session in mid-March, concern U-M researchers enough that they have launched a larger study of the issue.

"Heart patients seem to be turning to alternative therapies even more than the general population, even while they stick to mainstream drugs too," says Eva Kline-Rogers, R.N., M.S., the U-M nurse practitioner who coordinated the study. "But they may not know that some of these substances could pose a hazard when taken with certain heart medications, and if they don't tell their doctors, the risk may go undetected. We need to encourage patients to be cautious, learn the risks, and share information with their health care providers."

The study involved 145 patients who had been hospitalized for heart attack or angina within six months before being surveyed by phone last year. It was designed by members of the U-M Cardiovascular Center and the U-M Complementary and Alternative Medicine Research Center, one of the first centers of its kind in the nation funded by the National Institutes of Health.

The study started after U-M cardiologists and nurses noticed that some patients came to their appointments with lists of all the prescription drugs, over-the-counter medicines, vitamins, minerals and food supplements that they were taking -- wondering which they could cut out to save money or reduce hassle.

The physicians would explain that the prescription medications had years of research evidence behind them to show that they worked, while many alternative treatments, even vitamins, had little or no scientific proof to back them up, and could cause side effects.

So, the researchers set out to see how many of their patients were using different diet, physical or body-mind techniques, what it was costing them, and whether they told their doctors about it.

They knew that previous studies by other teams had shown that nearly half of all Americans use alternative techniques -- everything from multivitamins to "energy healing" -- and that the annual cost totaled an estimated $21 billion. Research has also suggested that patients could face a risk of bleeding problems, including gastrointestinal bleeding or surgical complications, if they take certain mainstream medications along with certain alternative substances.

Many heart patients have a prescription to take aspirin, Coumadin (warfarin) or Plavix (clopidogrel), to thin their blood, prevent clotting, and reduce their risk of heart attack, stroke or other problems. But dietary supplements like gingko biloba, ginseng, garlic, vitamin E, fish oil or coenzyme Q10 can also cause blood-thinning (anticoagulant) effects, and doses aren't carefully studied and controlled like those for medicines. The total anti-clotting effect from taking both at once, or other interactions between drugs and supplements, are what worry experts.

Other complementary or alternative medicine (CAM) treatment approaches, from prayer, meditation and yoga to chiropractic and acupuncture sessions, do not pose a specific hazard when combined with conventional heart treatments. Many patients find them to be beneficial at reducing stress or increasing body function. They were also included in the U-M study.

The survey gave some surprising results. "Of the 145 patients surveyed, 74 percent reported using some sort of CAM therapy," says Kline-Rogers. "Sixty percent of the surveyed patients used supplements, vitamins or herbs, while 43 percent used mind-body or body techniques. Many patients used both."

Even when multivitamins and prayer, two widely used and accepted "alternative" approaches, were subtracted, 60 percent of all the patients used at least one remaining CAM technique. Most said they used CAM to help them heal or to ease their symptoms.

Among all the patients who used CAM techniques, 31.8 percent used at least one blood-thinning prescription medication and one diet supplement that could reduce clotting. This particular statistic troubles Kline-Rogers and her colleagues most. In the study they're now conducting, they're asking heart patients about their use of prescription medications and CAM techniques, their intake of beverages such as green tea and red wine that can also interfere with clotting, and their incidence of minor bleeding symptoms.

The vast majority -- 75 percent -- of people who chose food supplements, vitamins or herbs told their doctor what they were taking. The rest said they didn't think it was necessary, or didn't care to discuss it, or that their doctor didn't ask. Kline-Rogers and her colleagues were pleased by the high percentage of those who told their doctors. But they note that both clinicians and patients need more education about the importance of talking to one another about CAM use, due to the potential risks of bad interactions between CAM techniques and conventional ones.

When asked about their greatest concerns about CAM techniques, a majority of CAM users said they were worried their chosen approaches wouldn't work, or were a waste of money. On average, using prices from local stores and practitioners, patients spent about $10 a month on dietary CAM approaches, and $98 a month on body-based or mind-body approaches performed by practitioners such as chiropractors, acupuncturists, Reiki masters and yoga instructors.

Besides Kline-Rogers, the study's authors include U-M pre-med students Prasanth Lingam and Sumit Sharma; U-M-Pfizer pharmacoeconomics fellow Christopher McBurney, Pharm.D.; U-M CAM Research Center co-director Sara Warber, M.D.; and cardiologists Rajendra Mehta, M.D., M.S. and Kim Eagle, M.D. The study was conducted under the Michigan Cardiovascular Outcomes Research and Reporting Program, or M-CORRP.