The study comes after at least five previous studies that found varying results. Three did not report success with intercessory prayer but two did.
The latest study, released Thursday (March 30), was the most extensive. It involved 1,802 coronary artery bypass graft surgery patients from six hospitals who were divided into three groups: 604 received intercessory prayer after learning they might or might not be prayed for by others; 597 did not receive prayer after being told they might or might not receive it; 601 received intercessory prayer after learning they would receive it.
Investigators found that complications occurred in 52 percent of the first group, 51 percent of the second group and 59 percent in the third group.
"Our trial cannot be generalized to all forms of intercessory prayer," cautioned Dr. Charles F. Bethea, a principal investigator from Integris Baptist Medical Center in Oklahoma City, in a teleconference with reporters on Thursday. "But the role of awareness needs careful further study."
He said it is possible that patients' knowledge that they were the subject of intercessory prayer "might have induced a form of performance anxiety or made them feel doubtful about their outcome."
The Rev. Dean Marek, director of chaplain services at the Mayo Clinic in Rochester, Minn., said another possible cause for the different results is that patients who were prayed for "thought they were home free and discounted the traumatic effect that surgery has upon the body, so were ill-prepared for it."
The study, to be published Tuesday (April 4) in The American Heart Journal, analyzed patients between January 1998 and November 2000. Two Catholic groups and one Protestant group were given patients' first name and the first initial of their last name and asked to pray for them for two straight weeks, starting the night before the scheduled surgery.
The groups were faxed the names of the patients and asked to include the phrase "for a successful surgery with a quick, healthy recovery and no complications" to their usual prayers.
The study team also included participants from the Mind/Body Medical Institute in Chestnut Hill, Mass., Baptist Memorial Hospital in Memphis, Tenn.; Beth Israel Deaconess Medical Center in Boston; St. Joseph's Hospital in Tampa, Fla.; and Washington Hospital Center in the District of Columbia.