Study of the Therapeutic Effects of Intercessory Prayer (STEP) in Cardiac Bypass Patients: A Multicenter Randomized Trial of Uncertainty and Certainty of Receiving Intercessory Prayer

Herbert Benson, MD; Jeffery A. Dusek, PhD; Jane B. Sherwood, RN; Peter Lam, PhD; Charles F. Bethea, MD; William Carpenter, MDiv; Sidney Levitsky, MD; Peter C. Hill, MD; Donald W. Clem, Jr, MA; Manoj K. Jain, MD, MPH; David Drumel, MDiv; Stephen L. Kopecky, MD; Paul S. Mueller, MD; Dean Marek; Sue Rollins, RN, MPH; Patricia L. Hibberd, MD, PhD


Am Heart J. 2006;151(4):934-942. 

In This Article


Our study had 2 main findings. First, intercessory prayer itself had no effect on whether complications occurred after CABG. Second, patients who were certain that intercessors would pray for them had a higher rate of complications than patients who were uncertain but did receive intercessory prayer.

Although our study population appears similar and representative of CABG patients in the United States,[26] the proportion of patients in all 3 study groups who developed complications or major events was higher in our study population than reported elsewhere. These higher rates are likely attributable to our 100% audit of all case report forms against information in the medical record to ensure consistent and complete reporting of complications and major events after CABG. We do not believe that there was a differential reporting by treatment group because the independent auditor and site research nurses who completed the case report forms were unaware of patients' assignment.

Our findings are not consistent with prior studies showing that intercessory prayer had a beneficial effect on outcomes in cardiac patients.[7,8] Possible explanations for the lack of effect of intercessory prayer itself include the following. First, intercessory prayer may not be effective in reducing complications after CABG. Second, the magnitude of the reduction could be smaller than the 10% that our study was powered to detect. Third, the occurrence of any complication within 30 days of surgery may not be appropriate or relevant to the effects of intercessory prayer.

We have no clear explanation for the observed excess of complications in patients who were certain that intercessors would pray for them (group 3). Although postoperative atrial fibrillation/flutter was responsible for much of the excess of complications in the group 3 patients, this outcome is only one of the complications that contributed to the composite outcome,[27] and the excess may be a chance finding. Although there was a borderline excess of major complications (secondary outcome) in patients in group 1, this excess may also be well because of chance.

Our study had limitations: we placed constraints on how intercessory prayer was provided in this study. Although the intercessors were motivated to participate in the trial, they received limited information without feedback on the patient's condition, did not know or have any communication with patients or their families, used a standard study intention during their prayers, and prayed for patients in groups 1 and 3 for study-specific 14 days (anticipated maximum duration of inpatient stay for at least 95% of subjects). Before the start of this study, intercessors reported that they usually receive information about the patient's age, sex, and progress reports on their medical condition, converse with family members or the patient (not by fax from a third party), use individualized prayers of their own choosing, and pray for a variable period based on patient or family request. Our rationale for altering the way in which intercessory prayer is routinely provided was to enable us to standardize the initiation and duration of intercessory prayer, to assess compliance with provision of study prayer, and to direct the intercessors away from praying for everyone in the trial (by focusing on praying for those assigned to groups 1 and 3). The strict study instructions for providing intercessory prayer do not permit us to explore relationships between presence or absence of complications and the amount, duration, and timing of intercessory prayer.

We did not request that subjects alter any plans for family, friends, and/or members of their religious institutions to pray for them, because to do so would have been unethical and impractical. At enrollment, most subjects did expect to receive prayers from others regardless of their participation in the study. We also recognize that subjects may have prayed for themselves. Thus, our study subjects may have been exposed to a large amount of non–study prayer, and this could have made it more difficult to detect the effects of prayer provided by the intercessors.

The finding that intercessory prayer, as provided in this study, had no effect on complication-free recovery from CABG may be due to the study limitations. Understanding why certainty of receiving intercessory prayer was associated with a higher incidence of complications will require additional study.

Private or family prayer is widely believed to influence recovery from illness, and the results of this study do not challenge this belief. Our study focused only on intercessory prayer as provided in this trial and was never intended to and cannot address a large number of religious questions, such as whether God exists, whether God answers intercessory prayers, or whether prayers from one religious group work in the same way as prayers from other groups.


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