A Randomized, Controlled Trial of the
Effects of Remote, Intercessory Prayer on Outcomes in Patients Admitted
to the Coronary Care Unit
William
S. Harris, PhD; Manohar Gowda, MD; Jerry W. Kolb, MDiv; Christopher P.
Strychacz, PhD; James L. Vacek, MD; Philip G. Jones, MS; Alan Forker,
MD; James H. O'Keefe, MD; Ben D. McCallister, MD
Context Intercessory prayer (praying for others)
has been a common response to sickness for millennia, but it has
received little scientific attention. The positive findings of a
previous controlled trial of intercessory prayer have yet to be
replicated.
Objective To determine whether remote, intercessory
prayer for hospitalized, cardiac patients will reduce overall adverse
events and length of stay.
Design Randomized, controlled, double-blind,
prospective, parallel-group trial.
Setting Private, university-associated hospital.
Patients Nine hundred ninety consecutive patients
who were newly admitted to the coronary care unit (CCU).
Intervention At the time of admission, patients
were randomized to receive remote, intercessory prayer (prayer group) or
not (usual care group). The first names of patients in the prayer group
were given to a team of outside intercessors who prayed for them daily
for 4 weeks. Patients were unaware that they were being prayed for, and
the intercessors did not know and never met the patients.
Main Outcome Measures The medical course from CCU
admission to hospital discharge was summarized in a CCU course score
derived from blinded, retrospective chart review.
Results Compared with the usual care group (n=524),
the prayer group (n=466) had lower mean
SEM
weighted (6.350.26
vs 7.130.27;
P=.04) and unweighted (2.70.1
vs 3.00.1;
P=.04) CCU course scores. Lengths of CCU and hospital stays were
not different.
Conclusions Remote, intercessory prayer was
associated with lower CCU course scores. This result suggests that
prayer may be an effective adjunct to standard medical care.
Arch Intern Med. 1999;159:2273-2278
FROM TIME immemorial, prayer for the sick has been a common response
to the illness of a loved one. In some societies and among certain
religious groups, prayer is believed to be the most important therapy
that can be offered to a sick person, superseding even medical
intervention. Nevertheless, intercessory prayer (praying for others) has
rarely been subjected to scientific scrutiny. In 1988, Byrd
1
published the results of a blinded, controlled trial of 393 patients who
had been admitted to a coronary care unit (CCU) at San Francisco General
Hospital, San Francisco, Calif. Patients were randomly assigned to
either a usual care group, which received no organized prayer, or to an
experimental, intercessory prayer group, which received remote (from
outside of the hospital) prayer from persons unknown to them. Byrd
reported a statistically significant beneficial effect of intercessory
prayer as assessed by a summary "hospital course" score. Three
recent books on spirituality and healing2-4
have noted that the Byrd study is the only published trial of
intercessory prayer with clinically significant end points, and that
more scientifically valid (prospective, randomized, controlled, blinded,
etc) studies of prayer were needed. The purpose of the present study was
to attempt to replicate Byrd's findings by testing the hypothesis that
patients who are unknowingly and remotely prayed for by blinded
intercessors will experience fewer complications and have a shorter
hospital stay than patients not receiving such prayer.
METHODS
PATIENTS AND PROTOCOL
All patients admitted to the CCU at the Mid America Heart Institute (MAHI),
Kansas City, Mo, over a 12-month period were eligible for the trial (Figure
1). The only exceptions were those admitted for workup and
wait-listing prior to cardiac transplantation (because of anticipated
prolonged stays). Patients admitted for less than 1 day were
subsequently excluded because it took up to 24 hours for intercessors to
be contacted and prayer initiated. New admissions were identified in the
chaplain's office on a daily basis via computer. The chaplain's
secretary randomly assigned all new patients to either the usual care or
prayer group based on the last digit of the medical record number; even
numbers were assigned to the prayer group and odd numbers to the usual
care group. This allocation scheme allowed no opportunity for bias
because medical record numbers are assigned on a sequential basis to all
new patients entering the hospital, regardless of how sick they are. In
addition, since some patients were readmitted (having been assigned
their numbers months to years previously) and some were newly admitted,
no systematic assignment of the sickest patients to the odd (usual care)
group was possible. Once assigned, the secretary called an intercessory
prayer team leader and gave him/her the first name of the patient to be
prayed for. No other information (eg, diagnosis, prognosis, age, race,
socioeconomic status, or family situation) was available to the
secretary; thus, it was not passed on to the intercessors. The secretary
was the only person with knowledge of the assignment code, and she had
no contact with the patients, the CCU staff (she did not even know where
the unit was located within the hospital), the data collectors, or the
statistician, all of whom were blinded throughout. After receiving the
call from the secretary, the prayer team leader called the other 4
persons on his/her team and directed that the name of the new patient be
entered on a log sheet provided. The intercessors were asked to pray
daily for the next 28 days for "a speedy recovery with no
complications" and anything else that seemed appropriate to them. A
period of 28 days was chosen to ensure that prayer would continue
throughout the entire hospitalization of at least 95% of patients. Some
CCU patients (typically fewer than 5%) request prayer from the hospital
chaplain's staff upon admission to the hospital. When made, these
requests were always honored regardless of and without knowledge of
group assignment. This study was approved by the hospital's
institutional review board (IRB) and, in order to keep the study
blinded, was exempted from the requirement to obtain informed consent
(see the "Comment" section).
INTERCESSORS
The intercessors were recruited by the investigators via contacts in the
local community. In order to be an intercessor, an individual did not
need to be of any particular denomination, but he/she did need to agree
with the following statements: "I believe in God. I believe that He
is personal and is concerned with individual lives. I further believe
that He is responsive to prayers for healing made on behalf of the
sick." Once identified, the intercessors were organized into 15
teams of 5 members (a total of 75), each with 1 person designated as the
team leader. Intercessors were randomly assigned to teams; those within
a given team did not know the others in the same team, and prayer was
offered individually, not in groups.
DATA COLLECTION
Patient demographics and admission diagnoses were obtained from the
hospital computer system. All patient charts were reviewed
retrospectively by a blinded physician/investigator to collect
information regarding comorbid conditions at the time of admission,
length of CCU and hospital stay, and clinical outcomes. The latter were
defined as all new diagnoses, events, or procedures occurring at least
24 hours after admission to the CCU (to allow time for organized prayer
to begin) until discharge or death. Thus, if a patient who presented to
the emergency department with an acute myocardial infarction was
catheterized, revascularized, and then admitted to the CCU, these
events/procedures were not recorded as new CCU events. On the other
hand, if after the first day in the CCU, a patient developed unstable
angina, had a coronary angiogram, and had a subsequent revascularization
procedure, all of these were recorded as new events.
CLINICAL OUTCOMES
Since prayer was offered for a speedy recovery with no complications, it
was anticipated that the effect of prayer was unlikely to be evident in
any specific clinical outcome category (eg, the need for antibiotics,
the development of pneumonia, or the extension of infarction), but would
only be seen in some type of global score. Review of the medical
literature revealed no previously validated and standardized statistic
to quantitate severity of outcomes in critically ill cardiovascular
patients. Severity of illness or comorbidity scales, such as the Acute
Physiology and Chronic Health Evaluation (APACHE) score5
and Charlson scale,6
do exist, but these are prognostic tools designed to predict major
health outcomes for individual patients; they are not designed to
summarize a CCU course. Accordingly, before the trial began, 3
experienced cardiologists and 1 internist from MAHI and the University
of Missouri–Kansas City School of Medicine developed a weighted and
summed scoring system called the MAHI-CCU score (Table
1). The MAHI-CCU score is a continuous variable that attempts to
describe outcomes from excellent to catastrophic. For example, if, after
the first day in the CCU, a patient developed unstable angina (1 point),
was treated with antianginal agents (1 point), was sent for heart
catheterization (1 point), underwent unsuccessful revascularization by
percutaneous transluminal coronary angioplasty (3 points), and went on
to coronary artery bypass graft surgery (4 points), his weighted
MAHI-CCU score would be 10. Another patient might have developed a fever
and received antibiotic treatment (1 point) but experienced no other
problems and been discharged from the hospital with a score of 1. A
third patient might have suffered a cardiac arrest (5 points) and died
(6 points), for a total weighted score of 11 points. In addition to the
weighted MAHI-CCU scores, a nonweighted MAHI-CCU score was calculated
that was simply a count of events, procedures, and/or prescriptions
after CCU admission. For the examples above, the unweighted MAHI-CCU
scores would have been 5, 1, and 2, respectively. To evaluate interrater
reproducibility for the MAHI-CCU score, 10 physicians (5 cardiologists
and 5 cardiology fellows) blindly scored 11 randomly selected CCU
patient charts. The raters were in agreement (meanSD)
96%3% of
the time. Finally, for comparison, the Hospital Course Score used by
Byrd1 was also calculated. The Byrd score
broadly categorizes each patient's progress after CCU admission as good,
intermediate, or bad.
STATISTICAL ANALYSIS
Baseline variables and specific medical outcomes were analyzed by
2
analysis and the Fisher exact test for categorical data. Byrd scores
were analyzed by the Cochran-Armitage test for trends7;
t tests were used to compare continuous variables (eg, age,
length of stay, and MAHI-CCU scores). A difference with a 2-tailed P<.05
was accepted as statistically significant, except for comorbid
conditions upon admission (Table
2) and individual events/procedures occurring during the CCU stay (Table
3). For these 2 data sets, P<.005 was required for
statistical significance because of the multiple comparisons evaluated.8
Data are presented as meansSEs.
All analyses were carried out blindly on an intention-to-treat basis
using SAS, version 6.12 (SAS Institute, Cary, NC).
RESULTS
INTERCESSORS
The intercessors represented a variety of Christian traditions, with 35%
listing their affiliations as nondenominational, 27% as Episcopalian,
and the remainder as other Protestant groups or Roman Catholic. The
intercessors were predominantly women (87%), and their mean age was 56
years. All reported at least weekly church attendance and daily prayer
habits (prior to the study). A review of intercessor log sheets
indicated that prayer (by at least 1 intercessor) began within 1.20.05
days after admission to the CCU. All intercessors who were ultimately
going to pray for a given patient began doing so within 1.60.16
days after CCU admission.
PATIENTS
A total of 1019 patients were admitted to the CCU during the period of
the trial. After elimination of 6 patients who were waiting for cardiac
transplantation, 1013 were randomized (Figure
1), 484 (48%) to the prayer group and 529 (52%) to the usual care
group. This difference in sample sizes was most likely caused by chance
(P=.18). After subsequent removal of those patients who spent
less than 24 hours in the CCU, 524 remained in the usual care group and
466 in the prayer group. Comorbid conditions upon admission were similar
for each group (Table
2). Men and women were equally represented in the usual care and
prayer groups (66% vs 61% men, respectively; P=.10), and the mean
age was 66 years for both groups.
OUTCOMES
The primary predefined end point in this trial was the weighted MAHI-CCU
score (Table
4). We found an 11% reduction in scores in the prayer group (6.350.26)
compared with the usual care group (7.130.27)
(P=.04). Using the unweighted MAHI-CCU score, which simply
counted elements in the original scoring system without assigning point
values, the prayer group had 10% fewer elements (P=.04) than the
usual care group. There were no statistically significant differences
between groups for any individual component of the MAHI-CCU score (Table
3). Mean lengths of stay in the CCU and in the hospital (after
initiation of prayer) were not different (Table
4), and median hospital stay was 4.0 days for both groups. There
were 2 patients in the prayer group whose hospital stays were
approximately twice as long (137 and 161 days) as those of any other
patient in the study. Without these 2 patients, length of hospital stay
for the prayer group dropped from 6.480.54
days to 5.840.31
days. Neither was significantly different from the length of stay in the
usual care group (5.970.29
days). There was no significant difference between groups using Byrd's
hospital course score (Table
5).
COMMENT
Using a severity-adjusted outcomes score, we found lower overall
adverse outcomes for CCU patients randomized to the prayer group
compared with those randomized to the usual care group. Lengths of CCU
stay and hospital stay after initiation of prayer were not affected.
These findings are consistent with those of Byrd,1
who reported that intercessory prayer for hospitalized patients lowered
the hospital course score but did not significantly affect length of
stay.
Although there was a trend toward better outcomes in the prayer group
using the Byrd score, the difference between groups was not
statistically significant. Other than the fact that it is a categorical
instead of a continuous statistic, we have no explanation as to why the
Byrd score did not detect a difference between groups and the MAHI-CCU
score did. There were, however, several important differences between
the 2 study designs that may have contributed to this discrepancy.
First, the present study was conducted under completely blinded
conditions, with neither patients nor medical staff aware that a study
was being conducted. In Byrd's trial, the staff and patients were fully
aware that the study was in progress, although nobody knew which
patients were receiving "study" prayer. Another difference was
in the kinds of patients enrolled. In the present trial, informed
consent was not sought and thus patients were not prescreened for their
willingness to be prayed for. Of the 450 patients invited to participate
in the Byrd study, 57 (12.7%) refused to do so "for personal
reasons or religious convictions" or were otherwise unwilling to
give consent. This indicates that only "prayer-receptive"
patients were included in his final cohort. Finally, in Byrd's study,
the intercessors were given a considerable amount of information about
the patient (eg, diagnoses, general conditions, and updates as their
status changed), and they prayed only until the patient left the unit.
These factors could have produced a heightened intensity of or
commitment to prayer in Byrd's intercessors. In contrast, our
intercessors were asked to pray for 28 days regardless of what happened
to the patient, and our intercessors received no feedback regarding
patient progress during this time. Whether this affected their
commitment to continued prayer is not known.
As noted above, both patients and staff were completely blinded not
only to assignment of treatment groups, but to the very existence of the
trial. This was possible because the hospital's IRB granted the study an
exemption from the requirement to obtain informed consent. Since this
may be viewed as problematic by some, the reasons supporting this
decision will be discussed in some detail. First, it was agreed that
there was no known risk associated with receiving remote, intercessory
prayer, and no known risk for the patients in the usual care group
associated with not receiving extra prayer. Second, no additional data
were collected on the patients in this study beyond those that are
normally collected for all patients in the hospital. Third, and perhaps
most important, the very process of obtaining informed consent could
conceivably have caused increased anxiety in some patients. For example,
had they known about the study, the possibility of not being in the
prayer group might have greatly distressed some patients. For
nonreligious or antireligious patients, having to accept or reject the
offer of prayer (especially considering the gravity of their illness)
might have been very challenging. The policy of the US Department of
Health and Human Services for the protection of human subjects states
that the
IRB may waive the requirement for the investigator to obtain a
signed consent form for some or all subjects if it finds . . . that
the research presents no more than minimal risk of harm to subjects
and involves no procedures for which written consent is normally
required outside of the research context.9
Scientifically, a study design with complete blinding was preferred
because it eliminated any possibility of bias, and enrolling all
patients in the study increased its generalizability. In light of all
these factors, an exemption was granted.
In evaluating the results of this trial, it is important to note that
we were most likely studying the effects of supplementary intercessory
prayer. Since at least 50% of patients admitted to this hospital state
that they have a religious preference, it is probable that many if not
most patients in both groups were already receiving intercessory and/or
direct prayer from friends, family, and clergy during their
hospitalization. Thus, there was an unknowable and uncontrollable (but
presumed similar) level of "background" prayer being offered
for patients in both groups; whatever impact that group assignment had
on healing was over and above any influence background prayer may have
had.
Neither this study nor that of Byrd provided any mechanistic
explanation for the possible benefits of intercessory prayer. However,
others have speculated as to what they might be10;
they generally fall into 2 broad categories: natural or supernatural
explanations. The former explanation would attribute the beneficial
effects of intercessory prayer to "real" but currently unknown
physical forces that are "generated" by the intercessors and
"received" by the patients; the latter explanation would be,
by definition, beyond the ken of science. However, this trial was
designed to explore not a mechanism but a phenomenon. Clearly, proof of
the latter must precede exploration of the former. By analogy, when
James Lind, by clinical trial, determined that lemons and limes cured
scurvy aboard the HMS Salisbury in 1753, he not only did not know about
ascorbic acid, he did not even understand the concept of a
"nutrient." There was a natural explanation for his findings
that would be clarified centuries later, but his inability to articulate
it did not invalidate his observations.
Although we cannot know why we obtained the results we did, we can
comment on what our data do not show. For example, we have not proven
that God answers prayer or that God even exists. It was intercessory
prayer, not the existence of God, that was tested here. All we have
observed is that when individuals outside of the hospital speak (or
think) the first names of hospitalized patients with an attitude of
prayer, the latter appeared to have a "better" CCU experience.
Although our findings would be expected to occur by chance alone only 1
out of 25 times that such an experiment was conducted, chance still
remains a possible explanation of our results.
Interest in alternative or complementary medicine is growing rapidly
in this country,11,
12 and prayer "therapy" falls into
this category. Two recent books3, 4
have focused on the health benefits of a patient's own spiritual
orientation. Each has documented that church membership/attendance is
associated with improved medical outcomes.13-15
People who believe in God and pray during illness have been reported to
have better health outcomes than people who do not.16-18
For some, faith is an effective means of stress reduction, which has
itself been shown to reduce cardiac morbidity.19
Some of these benefits may derive from favorable hormonal, autonomic,
and immunologic20,
21 responses to the emotional reassurance that
belief can provide. Nevertheless, the present trial was designed to
study the impact not of personal spirituality, but of prayer offered for
patients regardless of their spiritual orientation.
Other studies besides Byrd's have explored the impact of intercessory
prayer on health outcomes. O'Laoire22
examined the effects of intercessory prayer on self-esteem, anxiety, and
depression in 406 subjects (who received either no prayer, directed
prayer, or nondirected prayer) and in the 90 intercessors. There were no
specific benefits detected for the prayer groups. A pilot study of the
effects of intercessory prayer on 40 recovering alcoholics likewise
reported no clinical benefit.23
Finally, in a 6-month trial of "distant healing" in patients
with acquired immune deficiency syndrome, Sicher et al24
found statistically significant benefits for the intervention group
(fewer new illnesses, physician visits, hospitalizations, and days of
hospitalization; lower illness severity scores; and improved mood
scores). These studies illustrate the broadening scope of interest in
remote therapies and suggest that scientifically valid, properly
controlled studies can be carried out in this emerging arena.
The principal limitation of this study was defining the end point
measure (ie, determining some way to quantify how well a patient did
during a CCU stay). The score we devised, although intuitive and evenly
applied to both groups, has not been validated. (It should be noted that
the Byrd score is likewise an unvalidated measure of CCU outcomes.) It
is not immediately obvious how any score could be validated given the
fact that there is no known criterion standard summary statistic with
which we could compare the MAHI-CCU score. The fact that there were
significantly fewer total events in the prayer group suggests that the
observed difference between groups was not an artifact of the scoring
system. Another limitation lies in interpreting the clinical
significance of a 10% difference in MAHI-CCU scores. Since the score
itself is only an estimate of overall CCU course, there is no known way
to ascribe a clinical significance to it, other than to say that as a
group, the patients in the prayer group "did 10% better." The
score should be viewed only as a summary statistic designed to detect
the impact of a mild global intervention on overall health in large
groups, not in individual patients.
In conclusion, using the MAHI-CCU scoring system, we found that
supplementary, remote, blinded, intercessory prayer produced a
measurable improvement in the medical outcomes of critically ill
patients. Our findings support Byrd's conclusions despite the fact that
we could not document an effect of prayer using his scoring method. With
2 randomized, controlled trials now suggesting the possible benefits of
intercessory prayer, further studies using validated and standardized
outcome measures and variations in prayer strategy are warranted to
explore the potential role of prayer as an adjunct to standard medical
care.
Author/Article Information
From the Mid America Heart Institute, Saint Luke's Hospital, Kansas
City, Mo (Drs Harris, Vacek, O'Keefe, and McCallister and Messrs Kolb
and Jones); the Division of Cardiology, Department of Medicine,
University of Missouri–Kansas City (Drs Gowda and Forker); and the
Department of Preventive Medicine, University of California, San Diego
(Dr Strychacz).
Corresponding author: William S. Harris, PhD, Lipid Research Laboratory,
Saint Luke's Hospital, 4401 Wornall Rd, Kansas City, MO 64111 (e-mail: wharris@saint-lukes.org).
Accepted for publication May 3, 1999.
The authors are indebted to Tracy Isaacson, the secretary to Chaplain
Kolb, for assigning patients to study groups and contacting the
intercessors and to Shubha Gowda, MD, for helping with chart review. The
support of the associate chaplains at Saint Luke's Hospital was also
much appreciated. The encouragement and support of Richard G. Hastings,
Douglas Willhoite, MD, and Robert and Marie Evans were greatly
appreciated, as was the critical review provided by John Spertus, MD.
Finally, we are indebted to the intercessors for faithfully praying for
the patients in this study.
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