A recent study of nearly 500 doctors who help write cardiovascular clinical practice guidelines found that more than half of them reported having at least one conflict of interest-and many have relationships with major medical companies, including Fridley-based Medtronic, Inc.

The study, which was released by the American Medical Association in the Archives of Internal Medicine, found that 56 percent of the 498 doctors included in it reported a conflict of interest.

According to the study, conflicts of interest include receiving a research grant, being on a speaker's bureau and/or receiving honoraria, owning stock, and being a consultant or member of an advisory board.

The most common conflict reported by the doctors was being a consultant or member of an advisory board of a company-and Medtronic was named as one of the companies that doctors most often have a relationship with.

Medtronic spokesman Christopher Garland said in an e-mailed statement that Medtronic reviewed the study and wasn't surprised that the company “would be named in association with many of the guideline participants” because the study looked at practice guidelines that deal with cardiovascular diseases.

“Medtronic is the leading medical device company in the cardiovascular space being involved in more therapies in that space than any other company,” Garland wrote, adding that collaboration leads to better therapies and products.

“What is important to note here is that the purpose of disclosure is transparency, not exclusion, and giving advice to a company or receiving a research grant does not mean that person has a bias or has lost the ability to have independent thought,” Garland wrote.

The study examined the 17 most recent American College of Cardiology and American Heart Association guidelines through 2008. In addition to Medtronic, several other companies were cited in the study for having relationships with doctors, including major drug companies Pfizer and Merck.

The study said that conflicts of interest are found in all spheres of medicine, but their role in the creation and formation of clinical practice guidelines may be especially significant.

“Improper bias in the [clinical practice guidelines] production process can have a potentially more widespread adverse effect on patient care than individual practitioners' [conflicts of interest],” the study said.

Researchers from the University of Pennsylvania led the study, which was released Monday.