Placebo Effect could Skew Tests of New Therapies
         From the corporate.dukehealth.org archives. Content may be out of date.
        From the corporate.dukehealth.org archives. Content may be out of date.
    
AMSTERDAM - Clinical trials that only use a cardiac
    patient's quality of life as a measure of treatment success may
    skewresults due to a prominent "placebo effect," researchers
    caution.
In a unique study, investigators at Duke Clinical Research
    Institute Durham, N.C., looked at whether a patient's
    assessment ofhis or her own health status - a frequent
    "endpoint" in clinical trials of novel therapies - bore any
    relationship to the actual clinicaloutcome they had, based on
    the treatment they received.
In a study of 1,189 patients with severe coronary artery
    disease, researchers found that the treatment patients received
    -aggressive or not - had no impact on their sense of
    well-being. All patients in the study rated their health status
    as similarlyimproved since coming under a doctor's care.
But such a bright outlook was not always reflected in
    mortality figures. Death rates for patients for whom only drug
    therapy wasavailable were twice as high compared to those who
    received heart bypass surgery or an angioplasty procedure to
    clearclogged heart passages.
The study was a surprise to researchers, who say it points
    out a prominent "placebo effect" that can be slanting the
    results ofclinical trials that judge success based on
    quality-of-life indicators.
"Even the sickest patients in this study, those for whom
    revascularization wasn't an option, felt better during the time
    they werebeing followed by physicians," said Duke cardiologist
    Dr. James Jollis, who led the study. "When you take care of
    patients overtime and follow their progress, the placebo effect
    can be strong."
He prepared his study for presentation Aug. 28 at the 22nd
    annual congress of the European Society of Cardiology.
    The studywas funded by Genentech Inc., of South San Francisco,
    Calif.
Jollis noted that trials of several new techniques, such as
    myocardial laser perforation and the use of vascular growth
    factors,have relied on general health status instead of "harder
    endpoints such as death or costs."
For example, recent tests of vascular growth factors have
    been negative because patients in both the test and control
    groupsboth have shown improvement. The unexpected improvement
    among placebo patients could lead to falsely negative
    findings,Jollis said. "Based on the Duke analyses, such trials
    may have been positive if more patients had been included," he
    added.
"There are many more things that affect the way patients
    feel other than just the status of their hearts," he said.
    "Variables canrange from non-cardiac illnesses to non-medical
    issues, such as social, psychological and economic factors.
"Our data suggest that qualify-of-life measures vary little,
    such that many patients would be required to detect a
    treatmentbenefit, while mortality and cost vary greatly, such
    that fewer patients would be required to detect a benefit,"
    Jollis said.
This is important because the number of patients with
    "end-stage" coronary artery disease - those for whom bypass
    surgery orangioplasty is no longer an option - "continues to
    grow" and, consequently, more therapies are being designed to
    treat them,Jollis said. "It's important that these new
    therapies be tested and measured in such a way that it
    demonstrates theireffectiveness."
The Duke study specifically picked a group of patients with
    severe coronary disease to study because they expected
    thatpatients who received revascularization procedures (bypass
    surgery or angioplasty) would report a higher quality of
    life,compared to patients who could only be treated with
    medicine. Optimal treatment for such disease is
    revascularization, but inthis study, 487 patients (41 percent)
    could not undergo the therapy due to their coronary anatomy or
    excess risk of death.
Patients were asked to complete two questionnaires after
    treatment and then at one and two years of follow-up study.
    Onequestionnaire consisted of a 36-item health survey on such
    topics as general health perceptions, physical functioning,
    bodily painand general mental health. The other asked patients
    to rank the ease with which they are able to perform common
    activities ofdaily living.
Results show that patients who only received drug therapy
    had a similar pattern of positive change in their
    self-assessment ofphysical and emotional limitations.
    Functional status also improved for all patients, independent
    of their treatment.
But when data on death rates and cost of hospitalization
    were tallied on the same group of 1,189 patients, it was clear
    thatthose who had not qualified for a revascularization
    procedure did much worse, Jollis said.
After two years, mortality in patients who were treated with
    only medicine was 38 percent, compared to 15 percent in
    patientswho had an angioplasty and 19 percent for bypass
    surgery patients. During that follow-up period, hospital costs
    of $40,471was also substantially higher in the group that
    didn't have revascularization, compared to $34,785 for
    angioplasty patients and$24,005 for bypass patients.
"Remarkably, despite greater disease burden and mortality,
    patients with end-stage coronary artery disease do not
    perceivetheir health status to change in a significantly
    different fashion compared to patients still eligible for
    conventionalrevascularization," Jollis said. "These findings
    should inform the design of trials involving novel therapies,
    suggesting thatmortality and cost be included as primary
    endpoints when considering effectiveness."
