J Altern Complement Med. 2007 (Jun); 13 (5): 491–512 ~ FULL TEXT
Cheryl Hawk, D.C., Ph.D., Raheleh Khorsan, M.A., Anthony J. Lisi, D.C.,
Randy J. Ferrance, D.C., M.D., and Marion Willard Evans, D.C., Ph.D., C.H.E.S.
Cleveland Chiropractic College,
Kansas City, Missouri 64131, USA.
This systematic review of scientific literature identified 179 published papers that addressed chiropractic care for 50
different non-musculoskeletal conditions; 47 papers described experimental studies, including 14 randomized trials. Based on review of the controlled studies, the authors determined that there was evidence of the benefit of chiropractic care for patients with asthma, cervicogenic vertigo, and infantile colic, and potential benefit for children with otitis media and elderly patients with pneumonia.
OBJECTIVES: (1) To evaluate the evidence on the effect of chiropractic care, rather than spinal manipulation only, on patients with nonmusculoskeletal conditions; and (2) to identify shortcomings in the evidence base on this topic, from a Whole Systems Research perspective.
DESIGN: Systematic review.
METHODS: Databases included were PubMed, Ovid, Mantis, Index to Chiropractic Literature, and CINAHL. Search restrictions were human subjects, peer-reviewed journal, English language, and publication before May 2005. All randomized controlled trials (RCTs) were evaluated using the Scottish Intercollegiate Guidelines Network (SIGN) and Jadad checklists; a checklist developed from the CONSORT (Consolidated Standards of Reporting Trials) guidelines; and one developed by the authors to evaluate studies in terms of Whole Systems Research (WSR) considerations.
RESULTS: The search yielded 179 papers addressing 50 different nonmusculoskeletal conditions. There were 122 case reports or case series, 47 experimental designs, including 14 RCTs, 9 systematic reviews, and 1 a large cohort study. The 14 RCTs addressed 10 conditions. Six RCTs were rated "high" on the 3 conventional checklists; one of these 6 was rated "high" in terms of WSR considerations.
(1) Adverse effects should be routinely reported. For the few studies that did report, adverse effects of spinal manipulation for all ages and conditions were rare, transient, and not severe.
(2) Evidence from controlled studies and usual practice supports chiropractic care (the entire clinical encounter) as providing benefit to patients with asthma, cervicogenic vertigo, and infantile colic. Evidence was promising for potential benefit of manual procedures for children with otitis media and elderly patients with pneumonia.
(3) The RCT design is not necessarily incompatible with WSR. RCTs could improve generalizability by basing protocols on usual practice.
(4) Case reports could contribute more to WSR by increasing their emphasis on patient characteristics and patient-based outcomes.
(5) Chiropractic investigators, practitioners, and funding agencies should increase their attention to observational designs.
From the Full-Text Article:
The increasing emphasis on evidence-based health care
decision-making requires providers to understand the
documented outcomes of their treatments. To better inform
this decision-making, the Council on Chiropractic Guidelines
and Practice Parameters (CCGPP) developed a process
for evaluating the evidence for chiropractic care. Teams of
experts on methodology and practice were formed to address
various categories of conditions. This paper reports the
results of the compilation of evidence related to chiropractic
care for patients with nonmusculoskeletal conditions. We
defined these, for this review, as conditions in which the primary
symptoms are not related directly to the spine or musculature.
For operational purposes, our review specifically
excluded headaches, for two reasons: First, headaches were
included in the CCGPP category of “cervical spine,” and so
were addressed by that team; although migraines may not
be of musculoskeletal origin, they are often included in
headaches studies, along with tension headaches, and it
would be difficult to effectively tease out the nonmusculoskeletal
and musculoskeletal components.
topic of manipulative treatment of headache is quite extensive,
and would result in an unmanageably large paper if
combined with the nonmusculoskeletal literature in general.
Previous papers addressing this topic have relied primarily
on the results of randomized controlled trials (RCTs), and,
because of the paucity of such studies, have concluded that
evidence is insufficient. [1, 2] However, recently there has been
protest within the scientific community against the near-total
reliance on RCTs as a source of evidence.  Particularly for “complementary and alternative medicine” (CAM) practices,
observational studies reflecting usual practice are gaining
credibility.  This is especially relevant to “body-based”
practices, which do not lend themselves readily to blinding.
In its 2005 report on CAM, the Institute of Medicine recognized
the need to develop scientifically rigorous, yet appropriate,
methods to study CAM.  Whole systems research
(WSR) is a burgeoning methodological perspective that addresses
this need.  It emphasizes the importance of “model
validity,” that is, congruence between research methodology
and the paradigm of the system being investigated.  Demonstrating
the promising nature of WSR, the National Center
for Complementary and Alternative Medicine cosponsored a
symposium on WSR in 2002.  Application of WSR methods
to chiropractic research is as yet only theoretical. 
Therefore, we attempted not only to evaluate papers in
accordance with conventional standards, but also to view
them through a WSR perspective. The specific aims of this
review were to (1) evaluate the published evidence on the
effect of chiropractic care, rather than spinal manipulation
only, on patients with nonmusculoskeletal conditions; and
(2) identify specific shortcomings in the evidence base on
this topic, with respect to developing a whole systems approach
to research on the effects of chiropractic care.
There are several limitations to this study. First, the number
of studies on chiropractic care and/or SMT and other
manual therapies for patients with nonmusculoskeletal conditions
is relatively small, and the quality of the studies is
generally not high. The literature selection was limited to
English. It is possible that some studies were missed; however,
we used hand searching and input from content experts
to ensure a comprehensive search. Another limitation is the
possibility of bias in evaluating the studies. We attempted to
avoid this by using accepted checklists. A specific limitation
to the WSR checklist is that it has not been validated; it must
only be viewed as a first attempt to developing a systematic
method of representing a WSR perspective.
Implications for chiropractic practice
We have drawn several conclusions, from a pragmatic
perspective, regarding our first specific aim, to evaluate the
published evidence on the effect of chiropractic care on patients
with nonmusculoskeletal conditions.
The adverse effects reported for SMT for all age groups
and conditions were rare and, when they did occur, transient
and not severe.
Evidence from both controlled studies and usual practice
is adequate to support the “total package” of chiropractic
care, including SMT, other procedures, and unmeasured
qualities such as belief and attention, as providing
benefit to patients with asthma, cervicogenic vertigo, and
Evidence was promising for the potential benefit of manual
procedures for children with otitis media and for hospitalized
elderly patients with pneumonia.
Evidence did not appear to support chiropractic care for
the broad population of patients with hypertension, although
it did not rule out the possibility that there may
be subpopulations of hypertensive patients who might
Evidence was equivocal regarding chiropractic care for
dysmenorrhea and premenstrual syndrome; it is not clear
what level of biomechanical force is most appropriate for
patients with these related conditions. It does appear that
an extended duration of care, over at least 3 menstrual
cycles, is more likely to be beneficial.
There is insufficient evidence to make conclusions about
chiropractic care for patients with other conditions.
Implications for whole systems research in chiropractic
Regarding our second specific aim, to identify specific
shortcomings with respect to developing a whole-systems
approach to research on the effects of chiropractic care, we
have identified the following issues:
All studies, from case reports to RCTs, should routinely
report adverse effects.
Most published RCTs investigating chiropractic care for
nonmusculoskeletal conditions have not relied on usual
practice in designing their intervention protocols. Some
RCTs were designed without benefit of any published observational studies, case series, or case reports. Even in
the absence of observational studies, it is possible to
demonstrate that the protocol represents usual practice;
for example, the Olafsdottir et al.  infantile colic study
used a “reference group” of 14 practicing chiropractors
to establish the treatment protocol. We recommend that,
in the interest of generalizability, investigators carefully
review existing observational studies and reports, as well
as consult practitioners with experience treating patients
with the condition of interest, and design their intervention
protocols to reflect these.
Case series and case reports could increase their utility
in several ways:
a. Report patient-based outcomes using validated instruments
(rather than focusing on clinician-based
b. Specifically address occurrence of adverse effects;
c. Describe patient characteristics in greater detail;
d. Routinely include measures of expectation, satisfaction,
and other attitudinal assessments.
The RCT design is not necessarily incompatible with
WSR. For example, 1 of 6 RCTs scoring high on conventional
RCT checklists also scored high with our
preliminary list of WSR considerations. Considerations
in designing RCTs that are both rigorous by conventional
standards yet are consistent with WSR are
a. In reporting the results of intervention studies, investigators
should specify whether care was provided free
of charge and/or patients received incentives for participating.
Cost is an important consideration, and free
care and/or incentives may affect the generalizability
b. As described above, RCT protocols should have
greater reliance on procedures and treatment schedules
found in usual practice.
c. “Real-life” comparison groups such as no-treatment
or standard care are more generalizable; furthermore,
using soft-tissue treatment or other procedures that are
also used in everyday practice as shams or placebos
may confound results.
d. Routinely including patient-based functional outcome
measures, satisfaction, and quality of life provides
more multifactorial information on treatment effects.
e. Routinely including measures of patient and practitioner
preference and expectation provides important
information on psychosocial aspects of the clinical encounter
that may affect outcomes.
Educate chiropractic investigators, practitioners, and
funding agencies as to the value (or in some cases, the
existence of) observational designs such as cohort and
case–control studies, to avoid use of scarce resources on
premature and sometimes poorly conceived RCTs.
Some of the initial work involved in this project is related
to the Council on Chiropractic Guidelines and Practice
Parameters (CCGPP). We would like to thank John
Triano, D.C., Ph.D., CCGPP Research Commission Chair,
and Alan Adams, D.C., M.S., M.S.Ed., Research Commission
Vice Chair, for their work in developing the
groundwork for the CCGPP scientific process. However,
this paper represents only its authors’ views, not those of
We would like to thank Russell Iwami, M.L.S., at National
University of Health Sciences library and Diana Salinas,
Linda Horat, and Nehmat Saab, M.A., M.L.S., at Southern
California University of Health Sciences library for their
essential, and generous, contribution to the literature search
for this project. Without them this review would not have
been possible. We thank Ronald Rupert, M.S., D.C., Parker
Research Institute, for contributing his expertise to the literature
search. We also thank Maria Dominguez of the
Parker Research Institute, Anupama KizhakkeVeettil,
BAMS (Ayu), MAOM, of Southern California University
of Health Sciences, and Denise Graham of Cleveland Chiropractic
College for their assistance in paper retrieval and
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