Studies Focusing on Chiropractic
Wilk vs. AMA (American Medical Association) Lawsuit
inquiry that further validated chiropractic came about through
an antitrust suit filed by four members of the chiropractic
profession against the American Medical Association (AMA).
and a number of other medical organizations in the United
States (Wilk et al v. AMA et al, No.90-542, October 1990).
1987, following 11 years of legal action, a federal appellate
court judge ruled that the AMA had engaged in a "lengthy,
systematic, successful and unlawful boycott" designed
to restrict cooperation between MDs and chiropractors in
order to eliminate the profession of chiropractic as a competitor
in the United States health care system. During the proceedings
it was shown that the AMA attempted to :
insurance programs for Chiropractic patients
evidence of the effectiveness of Chiropractic care
government inquires into the effectiveness of Chiropractic
other activities that would control the monopoly that
the AMA had on health care
was upheld by the 7th United States Circuit Court of Appeals.)
AMA offered a patient care defense; however, data from Workmen's
Compensation Bureau studies served to validate chiropractic
care. Specifically, studies comparing chiropractic care
to care by a medical physician were presented which showed
that chiropractors were "twice as effective as medical
physicians, for comparable injuries, in returning injured
workers to work at every level of injury severity."
settlement of the suit included an injunctive order in which
the AMA was instructed to cease its efforts to restrict
the professional association of chiropractors and AMA members.
The AMA was also ordered to notify its 275,000 members of
the court's injunction. In addition, the American Hospital
Association (AHA) sent out 440,000 separate notices to inform
hospitals across the United States that the AHA has no objection
to allowing chiropractic care in hospitals.
the court findings and conclusions were released, a growing
number of medical doctors, hospitals, and health care organizations
in the United States have begun including the services of
research studies and various government inquiries have resulted
in increasingly widespread recognition of chiropractic,
and generally support the efficacy of chiropractic treatment.
Excerpts from some of these studies have been highlighted
Agency for Health Care Policy and Research
December 8, 1994, The Agency for Health Care Policy and
Research (AHCPR) of the U.S. Department of Health and Human
Services, released an extensive study of diagnostic and
treatment methods for acute low back pain. This condition
is the most common health complaint experienced by working
Americans today, and a condition which costs the economy
at least $50 billion a year in lost wages and productivity.
AHCPR panel -- a 23-member committee of medical doctors,
nurses, chiropractic doctors, experts in spine research,
physical therapists, a psychologist, an occupational therapist
and a consumer representative -- concluded, among other
spinal manipulation is a recommended treatment for acute
low back problems in adults;
conservative treatment such as manipulation should be
pursued -- in most cases -- before surgical interventions
prescription drugs such as oral steroids, antidepressant
medications and colchicine are not recommended for acute
low back problems.
Studies on Chiropractic - The Manga Report
report on the effectiveness of chiropractic treatment was
published in 1993. Tile report, entitled The Effectiveness
and Cost-Effectiveness of Chiropractic Management of Low-Back
Pain, was funded by the Ministry of Health in Ontario to
assess the most appropriate use of health care resources.
Ministry was particularly interested in reducing the incidence
of work-related injuries and in improving the rehabilitation
of disabled and injured workers. The report stated that
in the past year, "twelve to thirty percent of people
in modern industrialized societies reported low back pain.'
light of these concerns, a massive literature review on
the effectiveness and cost effectiveness of chiropractic
treatment was undertaken by an independent panel of researchers
associated with the University of Ottawa. Their findings,
outlined below, overwhelmingly support the efficacy and
cost-effectiveness of chiropractic for the treatment of
Scientifically valid clinical studies support the fact
that chiropractic spinal manipulation is "more effective
than alternative treatments for LBP (low-back pain). Many
medical therapies are of questionable validity or are
"There would be a highly significant cost savings
if more management of LBP was transferred from physicians
to chiropractors. Evidence from Canada and other countries
suggests potential savings of hundreds of millions annually.
The literature clearly and consistently shows that the
major savings from chiropractic management come from fewer
and lower costs of auxiliary services, much fewer hospitalizations,
and a highly significant reduction in chronic problems,
as well as in levels and duration of disability."
"There is no clinical or case-control study that
demonstrates or even implies that chiropractic spinal
manipulation is unsafe in the treatment of low-back pain.
Some medical treatments are equally safe, but others are
unsafe and generate iatrogenic complications for LBP patients
... The literature suggests that chiropractic manipulation
is safer than medical management of low-back pain."
"While it is prudent to call for even further clinical
evidence of the effectiveness and efficacy of chiropractic
management of LBP, what the literature revealed ... is
the much greater need for clinical evidence of the validity
of medical management of LBP. Indeed, several existing
medical therapies of LBP are generally contraindicated
on the basis of the existing clinical trials. There is
also some evidence in the literature to suggest that spinal
manipulations are less safe and less effective when performed
by non-chiropractic professionals."
"There is an overwhelming body of evidence indicating
that chiropractic management of low-back pain is more
cost-effective than medical management ... The evidence
includes studies showing lower chiropractic costs for
the same diagnosis and episodic need for care."
"There is good empirical evidence that patients are
very satisfied with chiropractic management of LBP and
considerably less satisfied with physician management.
Patient satisfaction is an important health outcome indicator
and adds further weight to the clinical and health economic
results favoring chiropractic management of LBP."
report concluded with various recommendations including
fully integrating chiropractic services into the health
care system, shifting policy to encourage and prefer chiropractic
services for most patients with low-back pain, employing
chiropractors in tertiary hospitals, and extending hospital
privileges to chiropractors.
following are summaries of additional Canadian studies on
A study of spinal manipulation involving 283 patients
with chronic low-back and leg pain was conducted at a
"specialized university back pain clinic reserved
for patients who have not responded to previous conservative
or operative treatment" located at the University
of Saskatchewan in Saskatoon, Saskatchewan. In this study,
which involved research conducted by both a medical doctor
and a chiropractor, all patients were initially classified
as totally disabled. Daily spinal manipulations were administered
and the effects of this treatment were assessed at one
month and at three months. Results revealed that 81% of
the patients became symptom free or achieved a state of
mild intermittent pain with no work restrictions. (Kirkaldy-Willis,
A study of 744 patients with neck and back pain who had
been referred from hospitals, private practice specialists,
general practitioners, and chiropractors analyzed tile
effectiveness of chiropractic manipulation. The results
revealed that 36% of the patients recovered (became symptom-free
with no work restrictions), 34.5% became much improved
(mildly symptomatic and able to function normally), 7.3%
slightly improved (possible activity restrictions), 21.6%
showed no change, and 0.6% became worse, The study also
revealed that "post- surgical patients do very well
under chiropractic care, and in fact at this center, patients
are routinely referred back to us three months after surgery
for maintenance care" (Potter 1977).
The Back Pain Clinic at the Royal University Hospital
in Saskatoon, Saskatchewan, reviewed literature pertinent
to "Side Posture Manipulation for Lumbar Intervertebral
Disk Herniation." The authors of the study concluded
that "the treatment Intervertebral disk herniation
by side posture manipulation is both safe and effective"
(Cassidy et al. 1993).
Studies on Chiropractic
addition to the Canadian studies previously cited, many
other studies have explored chiropractic treatment. These
have focused on tile effectiveness of chiropractic treatment
for back pain, for work-related Injuries, and for other
disorders. The following is a brief summary of some of these
RAND, a non-profit research organization, has completed
three studies in the United States on chiropractic, with
a fourth study currently underway.
first study, a population-based estimate concerning
the use of chiropractic services, reported in the American
Journal of Public Health, that "chiropractors deliver
a substantial amount of health care to the U.S. population,
and there are significant geographic variations in the
rate and intensity of use of chiropractic services"
second study, "Spinal Manipulation for Low-Back
Pain," published in the Annals of Internal Medicine,
affirmed that spinal manipulation is of benefit to some
patients with acute low-back pain (Shekelle and Adams
third study created two sets of appropriateness ratings
for spinal manipulation. One set of ratings was developed
by a multi-disciplinary panel and the other set was
prepared by an all-chiropractic panel (Shekelle et al.
fourth study, currently underway, is to determine the
types of health case problems for which people seek
chiropractic care and the types of care people receive
from chiropractors. This study is expected to be completed
In Australia, a 12-month study conducted by the Australian
Centre for Chiropractic Research included all work-related
low-back pain claimants. Individuals were identified who
received care either from a chiropractor or a medical
practitioner. The results indicated that:
chiropractic management was chosen fewer claimants required
compensation and fewer compensation days were taken
medical management was chosen, the average payment per
claim was greater and a greater number of patients regressed
to chronic status (Ebrall 1992).
A study reported in the British Medical Journal included
741 patients between the ages of 18 and 65 who suffered
from chronic or severe back pain and who sought care in
chiropractic and hospital out-patient clinics. After two
years of patient monitoring, researchers concluded that
"for patients with low-back pain in whom manipulation
is not contraindicated, chiropractic almost certainly
confers worthwhile, long-term benefit in comparison with
hospital out-patient management" (Meade et al. 1990).
Researchers conducted a study of workers' compensation
cases in Florida and concluded that "a claimant with
a back-related injury, when initially treated by a chiropractor
versus a medical doctor, is less likely to become temporarily
disabled, or if disabled, remains disabled for a shorter
period of time; and claimants treated by medical doctors
were hospitalized at a much higher rate than claimants
treated by chiropractors" (Wolk 1988).
From a survey of those receiving care from health maintenance
organizations (HMOs) in Washington state it was concluded
that "...patients of chiropractors were three times
as likely as patients of family physicians to report that
they were satisfied with the care they received for low-back
pain... Chiropractic patients were also more likely to
have been satisfied with the amount of information they
were given and to believe their doctor was concerned about
them" (Cherkin and MacComack 1989)
"Family Physicians, Chiropractors, and Back Pain,"
is the title of an article published in the Journal of
Family Practice (November 1992), addressing a comparative
United States study of patients of family physicians and
chiropractors. The article stated that "the number
of days of disability for patients seen by family physicians
was significantly higher (mean 39,7) than for patients
managed by chiropractors (mean 10.8)" (Curtis and
Bove 1992). A related editorial published in We same issue
of the Journal of Family Practice stated that family physicians
should accept the fact that "...spinal manipulation
is one of the few conservative treatments for low-back
pain that have [sic] been found to be effective in randomized
trials. The risks of complications from lumbar manipulation
are also very low" (Cherkin 1992). The latter conclusion
is supported by a study published by the Chiropractic
Journal of Australia which reported that "a descriptive
analysis of obtainable literature on complications from
low-back SMT (spinal manipulation treatment) from 1911
to 1991 indicates that, on the average, less than one
case per year occurs" (Terrett and Kleynhans 1992).
The Journal of Manipulative and Physiological Therapeutics,
published in the United States, reported results of a
study of women between the ages of 20 and 49 with a history
of dysmenorrhea (painful menstruation); "
may be an effective and safe non-pharmacolocical alternative
for relieving the pain and distress of primary dysmenorrhea,
at least for a short period of time after treatment"
(Kokjohn et al. 1992).
A number of United States clinical studies cite success
rates ranging from 72% to 90% for the treatment of headaches
utilizing spinal manipulation therapy. For example, a
study reported in the American Chiropractic Association's
Journal of Chiropractic reported that 74.6% of patients
with recurring headaches, including those experiencing
migraines, were either cured or experienced reduced symptomatology
associated with their headaches after receiving chiropractic
manipulation. Most importantly, the success rate was maintained
two years after treatment ended (Wight 1978).
A number of studies have documented the effectiveness
of chiropractic treatment for a variety of other conditions
including soft tissue injuries and viscera' disorders
(Plaugher 1993; Lewit 1985; and Korr 1978).
Focusing on the Cost-Effectiveness of Chiropractic
chiropractors have promoted chiropractic management of back
pain as a cost effective approach to alleviating this condition.
The following studies support this assertion:
A study conducted in the United States involving 395,641
patients with one or more of 493 neuromusculoskeletal
conditions was undertaken to compare the health care costs
of patients who have received chiropractic treatment to
those treated solely by medical or osteopathic physicians.
The results showed that "patients receiving chiropractic
care experienced significantly lower health care costs
... (with) total cost differences on the order of $1000
over the 2-year period ..." The report concluded
that"... these preliminary results suggest a significant
cost-saving potential for users of chiropractic care."
The report of the study also suggests the need to re-examine
insurance practices and programs relative to chiropractic
coverage (Stano 1993).
The Florida study on workers' compensation claims, previously
cited in reference to back pain, found that "the
estimated average total cost of care, computed across
all the major categories of treatment cost, was substantially
higher for medical patients compared with chiropractic
patients..." The authors of the study included that
chiropractic care is more cost-effective in the treatment
of work-related back injuries than standard medical care
A 1988 workers' compensation study conducted in Utah assessed
the total cost per case of chiropractic care versus medical
care for conditions with identical diagnostic codes. The
results indicated that costs were significantly higher
for medical claims than for chiropractic claims, In addition,
the number of work days lost for those receiving medical
care was nearly 10 times higher than for those who received
chiropractic care (Jarvis, Phillips, and Morris 1991).
A comparison of the cost of chiropractic care versus the
cost of medical care for various health conditions (predominantly
low-back pain, spinal-related sprains, strains, dislocations,
arthritis, and disc disorders), revealed that "chiropractic
is a lower cost option for several prominent back-related
ailments ... If chiropractic care is insured to the extent
other specialists are stipulated, it may emerge as a first
option for patients with certain medical conditions. This
could very well result in a decrease in overall treatment
costs for these conditions" (Dean and Schrnidt 1992),
A review of data from over two million users of chiropractic
care in the United States was reported in the Journal
of American Health Policy. Initial analysis indicated
that "chiropractic users tend to have substantially
lower total health care costs" and "chiropractic
care reduces the use of both physician and hospital care"
(Stano et al. 1992).
A workers' compensation study conducted in Oregon (1990)
evaluated the loss of working time incurred by chiropractic
(DC) and medical (MD) claimants with disabling low-back
work-related injuries. Authors of the study concluded
that "the median time loss days for cases with comparable
clinical presentation (severity) was 9.0 for DC cases
and 11.5 for MD cases. Chiropractic claimants had a higher
frequency of return to work with one week or less of time
loss." (Nyiendo 1991).
A study, published in 1992, compared the cost-effectiveness
of chiropractic care to medical care in the commonwealth
of Virginia. The report of the study indicated that chiropractic:
minimal cost-increasing effects on insurance and may
in fact reduce insurance costs.
important therapeutic benefits at economical costs.
study also recommended that chiropractic care be a widely
available form of health care, and noted that it is a
growing and widely used component of the health care sector
and Public Opinion Surveys
studies have assessed the utilization and acceptance of
chiropractic services throughout Canada and the United States.
A few of these studies are described in subsequent paragraphs:
A survey in the province of Ontario revealed that a majority
of MDs in family practice (62%) were referring patients
to chiropractors. Nearly half of these MDs (42.3%) had
been referring patients for the past 1-5 years, with the
referral rate being slightly higher among MDs who had
graduated before 1960 (60%) and between 1960 and 1980
(63%) than for those who had graduated in the past 10
years (53.8%). In addition, the study revealed that 9.5%
of these MDs had received chiropractic care themselves
A Gallup poll conducted in the United States and reported
in March of 1991 examined the attitudes and behaviors
of both users and nonusers of chiropractic services. Of
the users of chiropractic services:
felt chiropractic treatment was effective;
than 80% were satisfied with their treatment;
73% felt most of their expectations had been met during
would see a chiropractor again for treatment of a similar
would likely see a chiropractor again for other conditions.
the non-users of chiropractic services:
indicated they would see a doctor of chiropractic for
a problem applicable to chiropractic treatment;
reported that someone in their household had been treated
by a chiropractor, and nearly 80% of those were satisfied
with that treatment.
A 1983 survey of North Dakota residents, also conducted
by the Gallup Organization, indicated that awareness and
use of chiropractic services in the state were very high.
Nearly 100% of the residents had heard of chiropractors,
and almost half of the residents (49%) reported that they
had been examined or treated by a chiropractor at some
time. One in six residents (17%) had seen a chiropractor
in the past year.
and Legal Inquiries
is legally recognized or allowed to be practiced without
official sanction in approximately 39 countries. Varying
degrees of investigation into the appropriateness of chiropractic
treatment preceded the official stance of these countries.
recent years, the Canadian and United States governments
have begun requiring that health professionals provide guidelines
for use in assessing the appropriateness of care. In an
attempt to address this requirement, 33 chiropractors in
North America were invited to participate in a conference
held in early 1992 at the Mercy Center in Burlingame, California.
A publication released in early 1993 entitled, Guidelines
for Chiropractic Quality Assurance and Practice Parameters,
related the proceedings of that conference.
April 1993, the Canadian Chiropractic Association sponsored
a conference in Toronto to establish clinical guidelines
for chiropractic standards of care in Canada. The participating
members included chiropractors from various chiropractic
organizations throughout Canada. Results of this conference
will be published in a report scheduled for release at the
end of 1993.
New Zealand Commission of Inquiry
particularly significant study of chiropractic was conducted
by the New Zealand Commission of Inquiry. In its 377-page
report to the House of Representatives, the Commission states
that their report followed an extended (two-year) inquiry
which at that time was "probably the most comprehensive
and detailed independent examination of chiropractic ever
undertaken in any country." Excerpts from the Commission's
"We entered into our inquiry in early 1978. We had
no clear idea what might emerge. We knew little about
chiropractors. None of us had undergone any personal experience
of chiropractic treatment. If we had any general impression
of chiropractic it was probably that shared by many in
the community: that chiropractic was an unscientific cult,
not to be compared with orthodox medical or paramedical
services. We might well have thought that chiropractors
were people with perhaps a strong urge for healing, who
had for some reason not been able to get into a field
recognized by orthodox medicine and who had found an outlet
outside the fringes of orthodoxy.
"But as we prepared ourselves for this inquiry it
became apparent that much lay beneath the surface of these
apparently simple terms of reference. In the first place
it transpired that for many years chiropractors had been
making strenuous efforts to gain recognition and acceptance
as members of the established health care team. Secondly,
it was clear that organized medicine the New Zealand was
adamantly opposed to this on a variety of grounds which
appeared logical and responsible. Thirdly, however, it
became only too plain that the argument had been going
on ever since chiropractic was developed as an individual
discipline in the late 1800's, and that in the years between
then and now the debate had generated considerable more
heat than light.
the end of the of the inquiry we found ourselves irresistibly
and with complete unanimity drawn to the conclusion that
modern chiropractic is a soundly-based and valuable branch
of the health care in a specialized area..."
conclusions of the Commission's report, based on investigations
in New Zealand, the United States, Canada, the United Kingdom,
and Australia, were as follows:
Modern chiropractic is far from being an "unscientific
Chiropractic is a branch of the healing arts specializing
in the correction by spinal manual therapy of what chiropractors
identify as biomechanical disorders of the spinal column.
They carry out spinal diagnosis and therapy at a sophisticated
and refined level.
Chiropractors are the only health practitioners who are
necessarily equipped by their education and training to
carry out spinal manual therapy.
General medical practitioners and physiotherapists have
no adequate training in spinal manual therapy, though
a few have acquired skill in it subsequent to graduation.
Spinal manual therapy in the hands of a registered chiropractor
The education and training of a registered chiropractor
are sufficient to enable him to determine whether... the
patient should have medical care instead of or as well
as chiropractic care.
Spinal manual therapy can be effective in relieving musculoskeletal
symptoms such as back pain, and other symptoms known to
respond to such therapy, such as migraine.
In a limited number of cases where there are organic and/or
visceral symptoms, chiropractic treatment may provide
relief, but this is unpredictable, and in such cases the
patient should be under concurrent medical care if that
Although the precise nature of the biomechanical dysfunction
and... the precise reasons why spinal manual therapy provides
relief have not yet been scientifically explained, chiropractors
have reasonable grounds based on clinical evidence for
their belief that symptoms of the kind described above
can respond beneficially to spinal manual therapy.
In the public interest and in the interest of patients
there must be no impediment to full professional cooperation
between chiropractors and medical practitioners.
to the New Zealand Inquiry, the Australian Federal Minister
of Health requested that a Committee be formed to consider
extending the scope of (government-funded) Medicare benefits
for certain services, including chiropractic.
Committee accepted all of the findings of the New Zealand
commission, and also noted the "significant shift in
the last decade in attitude ... towards the issue of scientific
research" in chiropractic. It also recommended funding
for chiropractic in hospitals and other public institutions,
and endorsed greater philosophical unity in chiropractic.
government's Commission on Alternative Medicine
noteworthy study was conducted in 1987 by the Swedish government's
Commission on Alternative Medicine. It reached conclusions
consistent with the New Zealand and Australian studies and
also stated that:
Chiropractors with the Doctor of Chiropractic degree should
become registered practitioners and be brought within
the national insurance system.
The university-level training of DCs is equivalent to
Swedish medical training.
DCs have competency in differential diagnosis and should
be regulated on a primary care basis.
Measures to improve cooperation between chiropractors,
registered medical practitioners and physiotherapists
are vital to the public interest
not attempt self-diagnosis or self-treatment based on these
reports. Please consult with Dr. Cady if you are
interested in following up on the information presented.