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FCER News Release
For Immediate Release: October 14, 1998
Contact: Robin R. Merrifield
1304
Perry Ave., Bremerton WA 98310
Phone:
800-343-0549 or 360-471-7837
Fax:
360-478-0834 • E-mail: FCERedit@aol.com
FCER Director of Research Anthony Rosner, Ph.D.,
Addresses the New England Journal of Medicine Study on Low Back Pain
Des Moines, Iowa-The Cherkin study that has just appeared in The New England
Journal of Medicine (October 8, 1998 issue) and appears to have taken the media by
storm is an inaccurate and unfortunate representation of the patients who normally seek
chiropractic care for low back pain. It underscores the dangers of generalizing the
results of randomized clinical trials which themselves represent a specialized application
of therapies under restrictions that are not necessarily indicative of either the actual
therapists or patients whom they see. Worse, its design flaws are so numerous and serious,
as will be summarized below, that its validity is compromised to the point of collapse.
The reader in any event is misled as to what is actually shown in the trial.
Validity of the intervention
To begin, one must be aware that several chiropractic techniques are applicable to the
management of low-back pain, some of which are low-force [Logan Basic Technique, Flexion-
Distraction, use of a drop table, or traction]. In this trial, only one
high-velicity
technique [side-posture] was applied--and this may not be equally effective for all
patients [particularly older people]. Furthermore, important ancillary procedures that are
intrinsic to the chiro- practic visit appear to have been denied to patients; in
particular, (a) extension exercises were forbidden; and (b) patients most likely were not
given any literature--even though these two options are considered to be part of a
customary chiropractic regimen for office visits. The implication is that both these
elements were only permitted in the other two arms [edu- cational booklet and McKenzie
method] of the trial reported. In short, chiropractic treat- ment in this particular trial
appears to be only a pale shadow of the actual therapy adminis- tered to patients in the
real world. The fact that back pain recurrences as reported by the authors were 50% by
the end of the first year and 70% by the end of the second year con- firms this point of
view, not only for chiropractic but for the McKenzie physical therapy modality as well.
Characteristics of the Medical Booklet
What was the purpose and what were the details of the arm of the trial involving the
educational booklet? One is left wondering what form of therapy this is supposed to
represent in real life, and whether any attention (and of what kind) was given to the
patient in addition to this literature. Finally, no details of any kind are provided as to
the presentation and actual content of the booklet.
Lack of sufficient attention to patient expectations
No details are provided as to how patients were polled regarding their expectations of
treatment, how the questioning was phrased, and whether the instrument was validated. The
consequences of patient expectations have been given inadequate attention. Once patients
were eligible to participate, how many refused to participate and for what reasons? The
percentage of patients who had prior chiropractic care for low back pain appears to be
substantially lower for those patients in the chiropractic arm (24%) than for either the
McKenzie or medical booklet cohorts (35% and 40% respectively). Yet the authors themselves
quote from another prominent investigation that "the British study found the benefits
of chiropractic treatment to be most evident among patients who had previously been
treated by chiropractors, a group presumably favorably inclined toward chiropractic care."
Consequently, one can easily argue that the patients in the chiropractic cohort appear to
be doomed to diminished outcomes.
Baseline characteristics
Baseline values regarding severity among the three groups tested appear to create a bias
in the outcomes. First, the chiropractic group shows the highest tendency in percentages
of patients who, due to low back pain and prior to their therapy, encounter (a) greater
than one day of bed rest (35% vs 24% and 22% for the McKenzie and booklet groups
respectively), (b) more than one day of work lost (39% vs 41% and 30% for the McKenzie and
booklet group), and (c) greater than one day of restricted activity (72% vs 65% and 52%
for the McKenzie and booklet cohorts).
Second, the initial bothersome and Roland-Morris disability scores of 4 and 7-8 are
substantially below the respective values of 6-7 and 10 which are more frequently observed
in trials involving significant low back pain. This means that any observed changes are
compressed within an artificially narrow range and that statistical variations become more
disruptive. The effect of both of these aberrations is to compromise the monitoring of
back pain resolution.
Patient Compliance issues
Sufficient details regarding patient compliance are lacking. In addition, there would
appear to be a wide variance between the percentage of patients therapists considered to
be the level of compliance (55%) as opposed to what patients in at least the McKenzie
groups have reported (78%). What were the levels recorded in both the chiropractic and
booklet groups? How, when, and how often was the question posed to study subjects? Since
compliance is closely linked to satisfaction and has a major bearing on outcomes, this
issue cannot be ignored.
Lack of convincing or meaningful cost data
There is no way to draw a meaningful conclusion from the cost data as presented. Requisite
statistics regarding costs are totally ignored, such that one cannot assess whether
costs follow a normal distribution or are skewed (and to different extents) in each of the
three regarding modalities. Furthermore, it is incomprehensible that the HMO costs
regarding laboratory services, medications, and radiology should constitute 50% of the
chiropractic bill when the norm within the United States indicates that about 80% of
chiropractic costs are borne within the therapist's office and 20% are allocated to
external services-while precisely the opposite distribution of percentages is observed in
the offices of allopathic physicians.
Patient exclusion
The grounds for exclusion and symptoms of sciatica were not provided. In addition,
patients' attitudes towards provider groups should have been assessed for inclusion in the
trial as these would have significant impact upon both their compliance and outcomes.
In summary, the study is a poor representation of therapies as applied to the live
patient in the physician's office. If left unanswered, these inquiries would appear to be
of sufficient import as to render the data seriously compromised and the study as a whole
unreliable. It would be a grievous error at this point to accept the study as Gospel and
the authors are invited to respond.
The Foundation for Chiropractic Education and Research (FCER) is the largest
not-for-profit chiropractic organization devoted solely to the funding and distribution of
chiropractic research. For more information on FCER, please call (800)637-6244.
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