PLoS One. 2016 (Aug 3); 11 (8): e0160037 ~ FULL TEXT
Blanchette MA, Stochkendahl MJ, Borges Da Silva R, Boruff J, Harrison P, Bussičres A.
Public Health PhD Program,
School of Public Health,
University of Montreal,
Montreal, QC, Canada.
BACKGROUND CONTEXT: Low back pain (LBP) is one of the leading causes of disability worldwide and among the most common reasons for seeking primary sector care. Chiropractors, physical therapists and general practitioners are among those providers that treat LBP patients, but there is only limited evidence regarding the effectiveness and economic evaluation of care offered by these provider groups.
PURPOSE: To estimate the clinical effectiveness and to systematically review the literature of full economic evaluation of chiropractic care compared to other commonly used care approaches among adult patients with non-specific LBP.
STUDY DESIGN: Systematic reviews of interventions and economic evaluations.
METHODS: A comprehensive search strategy was conducted to identify 1) pragmatic randomized controlled trials (RCTs) and/or 2) full economic evaluations of chiropractic care for low back pain compared to standard care delivered by other healthcare providers. Studies published between 1990 and 4th June 2015 were considered. Primary outcomes included pain, functional status and global improvement. Study selection, critical quality appraisal and data extraction were conducted by two independent reviewers. Data from RCTs with low risk of bias were included in a meta-analysis to determine effect estimates. Cost estimates of full economic evaluations were converted to 2015 USD and results summarized using Slavin's qualitative best-evidence synthesis.
RESULTS: Six RCTs and three full economic evaluations were scientifically admissible. Five RCTs with low risk of bias compared chiropractic care to exercise therapy (n = 1), physical therapy (n = 3) and medical care (n = 1). Overall, we found similar effects for chiropractic care and the other types of care and no reports of serious adverse events. Three low to high quality full economic evaluations studies (one cost-effectiveness, one cost-minimization and one cost-benefit) compared chiropractic to medical care. Given the divergent conclusions (favours chiropractic, favours medical care, equivalent options), mixed-evidence was found for economic evaluations of chiropractic care compared to medical care.
CONCLUSION: Moderate evidence suggests that chiropractic care for LBP appears to be equally effective as physical therapy. Limited evidence suggests the same conclusion when chiropractic care is compared to exercise therapy and medical care although no firm conclusion can be reached at this time. No serious adverse events were reported for any type of care. Our review was also unable to clarify whether chiropractic or medical care is more cost-effective. Given the limited available evidence, the decision to seek or to refer patients for chiropractic care should be based on patient preference and values. Future studies are likely to have an important impact on our estimates as these were based on only a few admissible studies.
From the FULL TEXT Article:
Low back pain (LBP) remains a leading cause of disability
worldwide, accounting for over 10% of the total of
‘years lived with disability’.  LBP is the most common
occupational injury in Canada and United States. [2, 3] It
is the leading cause of work absenteeism and ranks sixth
among health problems in terms of direct medical costs
in North America. 
The incidence of non-specific LBP has not significantly
increased in the last four decades. [5–7] However, a drastic
increase in the number of certificates of illness and
benefits paid for chronic disabilities resulting from LBP
has been reported in industrialized countries since the
1980s.  Such increase in disability level has had an
alarming impact on costs due to lost productivity, wage
replacement, and health care utilization. According to
the 2010 Global Burden of Disease Study, low back pain disability-adjusted life years increased from 58.2 million
in 1990 to 83.0 million in 2010.  With the hope of reducing
the significant health and economic burden associated
with LBP, researchers have examined the
effectiveness of numerous treatment options, including
manual therapy. [10–14]
Opinions vary widely on what causes LBP and how
best to manage it.  It is estimated that over 85% of
patients with LBP have symptoms that are ‘non-specific’
in nature since they cannot reliably be attributed to a
specific disease or anatomical structure.  Perhaps as
a result, relatively few treatment modalities for the management
of LBP have been shown to achieve superior
and sustained improvements in pain, physical function,
and disability. [17, 18] An example is spinal manipulative
therapy (SMT), which recent reviews did not find significantly
more effective than and other modalities. [11, 19, 20] SMT is often a core component of chiropractic
care , but chiropractic care is not restricted to the
use of SMT , and a range of other treatment modalities
may be offered exclusively or in combination with
SMT to potentially compliment or enhance treatment
outcome. Moreover, SMT is not performed exclusively
by chiropractors but is used extensively worldwide by a
range of other health care professionals. [11, 20] In the
case of SMT, studies on the effectiveness may guide clinicians
(chiropractors and others) in their choice of
treatment modality, but offer little information to patients,
policy makers, and third-party payers about the
clinical effectiveness and cost-effectiveness of standard
care offered by different providers.
Considering this, older reports [23, 24] have pointed
to chiropractic care as efficient for the treatment of
LBP because of the relatively low fee for service, the
use of ‘low tech’ therapies such as manual therapy, and
the low usage of costly investigations such as advanced
diagnostic imaging. However, when compared with
medical and physiotherapy care, economic reviews have
not been able to support this or provide clear guidance
to informed decision-making regarding the many available
provider options. [25, 26] This divergence in findings
may be partly due to the limited number of studies
of acceptable methodological quality [25, 27] and partly
because the previous systematic reviews have only included
partial economic evaluation (cost description,
cost analysis, and cost-outcome description). The last
systematic review of economic and clinical effectiveness
studies of chiropractic care was completed nearly a
decade ago and provided limited guidance.  We are
conducting this review with the hope of including more
high quality studies.
When evaluating standard care for LBP, decisions to
recommend any one option should preferably be based
on the clinical effectiveness, the cost-effectiveness, the
safety of the approach, and patient preference. [11, 19, 26]
Only full economic evaluation (cost-effectiveness analysis,
cost-utility analysis, cost-benefit analysis) of standard
care practice can provide adequate information
about resource inputs (costs) and outputs (health outcomes)  and evaluate whether healthcare resources
are being used optimally.  In order to better inform
patients, policy makers, and third-party payers about the
clinical effectiveness and cost-effectiveness of standard
chiropractic care for LBP in comparison to usual standard
care provided by other health care professionals, an
evidence synthesis is indicated.
The two main objectives of this review are
1) to estimate
the extent to which chiropractic care is effective for
adult patients with non-specific low back pain compared
to other conservative care approaches (for example,
medical care and physiotherapy) and
2) to estimate the
cost-effectiveness of chiropractic care for adult patients
with non-specific LBP compared with other conservative
To be eligible for inclusion, studies must meet the following
The study design is:
– a randomized controlled trial for the clinical
– a full economic evaluation (including costeffectiveness,
cost-utility, cost-benefit analyses,
and cost-minimization analysis alongside a clinical
trial ) for the economic studies.
The population under study is composed of adult
patients (≥18 years) with non-specific LBP with or
without sciatica of any duration. Studies reporting
multiple pain locations or spinal pain without separate
results for LBP will be excluded.
The intervention is chiropractic care. Studies that
evaluate chiropractic care as part of a combined,
multidisciplinary approach will be excluded unless
the chiropractic care part is evaluated separately.
Studies that evaluate specific treatment modalities
(for example, SMT) will be excluded.
The comparator is non-surgical, usual conservative
care delivered by other healthcare providers (for
example, medical therapy, physical therapy, or
acupuncture). Studies including surgical treatment
of LBP as the only comparator will be excluded.
The outcome must include – for the clinical
effectiveness studies – one or more of the following
primary or secondary effect measures:
Pain (for example, visual analog scale, numerical
rating scale, McGill pain score)
Functional status (for example, Roland-Morris
questionnaire, Oswestry Disability Index)
Global improvement (for example, the number of
patients reporting to have recovered)
– For the economic studies: an incremental measure of
the extra budget required to improve an additional unit
of outcome (that is, an incremental cost-effectiveness
ratio or an incremental net benefit measure) with the exception
of cost-minimization studies.
Studies must be published in English or French.
Studies without full-text manuscript available (for
example, abstracts, conference proceedings,
presentations) and duplicate study reports will be
excluded. Published study protocol will be registered
but not included in the data analysis.
Information sources and search
A comprehensive literature search will be conducted
using indexed subject headings and free text related to
the topic of interest in electronic health literature databases,
as well as gray literature sources (economic evaluations
only), to uncover potentially relevant studies.
With the exception of PubMed, the search will be limited
to studies published between 1990 and the search
date. Since the volume of literature on back pain is
impressive, we restricted search to 1990 (start date) as it
corresponds with the first potentially relevant studies in
this topic. This start date will enable us to select relatively
recent literature that is compatible with the contemporary
practice of both chiropractic and comparator
providers. The PubMed search will be used to retrieve
the most recent publications and restricted to items
published on or after 2014.
Searches will be conducted in the following electronic
databases: Ovid Medline, Ovid AMED, Ovid EMBASE,
CINAHL, the Cochrane Database of Systematic Reviews,
and PubMed. In addition, we will also search for economic
evaluations in the following: Index to Chiropractic Literature
(ICL), Cochrane Library, Health Technology Assessment
Database, and ECONLIT. Finally, a search of the
gray literature for economic evaluations will include the
websites of the following organization: Canadian Institute
for Health Information (CIHI), Canadian Agency for
Drugs and Technologies in Health (CADTH), Canadian
Institute of Health Research (CIHR), Tufts Medical Center
Cost-effectiveness Analysis Registry, Agency for Healthcare
Research and Quality, National Institute for Health
Research Health Technology Assessment program, and
National Institute for Health and Care Excellence (NICE).
The search strategy will be different for each database,
and the RCT filters for PubMed, Ovid Medline, AMED,
EMBASE, and CINAHL will be adapted from the
Cochrane Highly Sensitive Search Strategy for identifying
randomized trials in MEDLINE.  The search in
Cochrane will be limited to Cochrane Central (Trials) to
exclude other study designs. Two clinical librarians (JB
and PH), with experience in searching for systematic reviews,
developed a search strategy for each individual
database and will conduct the searches. The search strategy
for clinical effectiveness and for cost-effectiveness
can be found in Appendix 1 and 2, respectively. We will
screen the bibliographies of relevant publications,
including reviews and meta-analyses, for additional relevant
Titles and abstracts of studies identified from the literature
search will be combined using Endnote 14 and
screened for relevance by two independent reviewers to
identify all articles that any reviewer judges potentially
eligible. The same reviewers will independently apply
eligibility criteria to the full-text manuscript of all potentially
eligible studies. Disagreements will be discussed
until consensus. Disagreements will be resolved with arbitration
by a third reviewer if disagreements persist.
Quality assessment and analysis
All eligible studies on clinical effectiveness will be
assessed for methodological quality (risk of bias) by two
independent reviewers. Studies assessing clinical effectiveness
will be evaluated using 12 criteria recommended
by the Cochrane Back Review Group.  These criteria
include blinding of the patient, treatment provider, and
outcomes assessor. Studies that meet at least 6 criteria
out of 12 will be considered at low risk of bias, while the
others will be considered at high risk of bias.
Studies assessing costs will be evaluated using a recommended
tool for health economic evaluations, the
Drummond (BMJ) checklist. [29, 33, 34] This checklist
includes 35 items grouped into four broad categories:
general issues about study design, data collection, data
analysis, and interpretation of results. Any disagreements
between reviewers will be discussed until consensus
is reached or with arbitration by a third reviewer if
disagreements persist. The quality level (low, medium, high) of every study will be determined by agreement
between three investigators (AB, MAB, MJS). This will
enable the investigators to formulate a qualitative appreciation
of the complete study.
Data will be extracted separately by two independent
reviewers; any disagreements will be resolved through
discussion, with arbitration by a third reviewer if necessary.
Authors of potentially relevant studies will be contacted
regarding additional information or missing data.
Key findings from each study will be summarized and
presented in a summary tables. Two separate forms will
be used for clinical effectiveness studies and economic
evaluations. For clinical effectiveness studies, we will use
the Cochrane back review group data extraction form
. Extracted variables will include author and year;
country; participants, indication, setting; compared treatments;
time horizon, outcomes assessed; authors’ results;
Data from economic evaluations will be extracted using
a customized data extraction sheet (Additional file 1).
Extracted variables will include author and year; country;
type of economic evaluation; participants, indication,
setting; compared treatments; perspective; time horizon,
currency price (year); included costs, health effect (pain,
functional status, global improvement, health-related quality
of life, return to work); mean costs, mean qualityadjusted
life years (QALYs); incremental cost-effectiveness
statistics; limitations; and authors’ conclusion.
Measures of effect estimates
Continuous outcomes measured with the same instrument
(that is, pain measured with visual analog scale)
will be compared using mean difference, whereas continuous
outcomes measured with different instruments
(that is, functional status measured with Roland-Morris
or Oswestry tools) will be compared using standardized
mean difference. For dichotomous outcomes (that is, recovery,
return-to-work), a risk ratio will be generated.
Effect measures relating to the primary and secondary
outcomes of clinical effectiveness studies with low risk
of bias, and no serious flaw will be evaluated for inclusion
in the meta-analyses. Outcomes will be assessed at
1, 3, and 12 months and will be categorized according to
the time closest to these intervals. In order to minimize
clinical diversity, we will stratify by healthcare provider
(for example, chiropractic care versus medical care or
chiropractic care versus physiotherapy), symptom duration
(acute (0 to 6 weeks), sub-acute (6 to 12 weeks),
chronic (more than 12 weeks), and mixed/not specified),
and outcomes (type of outcome and time of assessment).
Heterogeneity will be investigated by subjective interpretation
and by statistical testing using the Q and I
test. A cutoff of 40% at the I
2 test will determine the
limit of acceptable heterogeneity. If the I
2 cutoff is
exceeded or the description of the average care provided
by the comparator seems too heterogeneous, results will
be discussed narratively in the manuscript without
pooled estimates. A sensitivity analysis will be performed
by including studies with high risk of bias. Funnel plots
will be constructed using all data from the primary outcomes
regardless of the comparator or follow-up interval
in order to evaluate possible publication bias.
For the economic evaluations, the difference in perspective
of analysis, type of economic analysis, and
healthcare system will be discussed narratively. To allow
direct comparisons across countries and years, we will
convert reported costs estimates to 2014 United States
(US) dollars. International exchange rate based on purchasing
power parities (PPP) will be use to convert cost
estimates to US dollars, and gross domestic product
(GDP) deflators will be use to convert cost estimates to
2014. PPP and GDP are available from the World
Economic Outlook Database (http://www.imf.org/external/
data.htm). Results comparing chiropractic to other
types of care will be summarized using Slavin’s 
qualitative best-evidence synthesis approach, which assumes
that the strength of a relationship between variables
is based on the quantity and quality of the
evidence available. This approach aims to provide methodological
rigor by clearly and concisely articulating the
synthesis criteria and was recently used in a number of
systematic reviews related to occupational health. [37–39]
The level of evidence uncovered for the findings of interest
will be assessed using a 5–point ordinal scale (strong,
moderate, limited, mixed, and insufficient evidences) defined
by Slavin.  The appropriate level of evidence for
each finding will be assessed in a stepwise manner by first
determining if criteria for the highest level of evidence
(that is, strong) are fulfilled and, if they are, no further
evaluation is performed. If those criteria are not fulfilled,
those for the next lowest level of evidence are then
assessed, continuing until the appropriate level of evidence
can be assigned to the various review findings.
for each level of evidence are the following:
Minimum of three high quality studies; at least three
quarters of high and medium quality studies must concur
Minimum of two high quality studies or three of
medium and high quality; more than two thirds of all
studies must report consistent findings.
Minimum of one high quality study or two medium
quality studies, more than 50% of all studies must report
Findings from medium and high quality studies are
No high quality studies; one or no medium quality studies;
any number of low quality studies.
Our protocol is registered on PROSPERO (CRD4201
4008746), http://www.crd.york.ac.uk/PROSPERO. This
manuscript conforms to the PRISMA guidelines 
that are relevant to the reporting of a systematic review
protocol. We present our methods and analysis for the
review of clinical effectiveness and our review of economic
Our research team includes French and English investigators.
The potential of omitting important studies in
other languages is considered very small since chiropractic
is of English/American origin and is primarily practiced
in the anglophone countries.
Decisions regarding optimal care should be based on
aspects of importance to all stakeholders, including clinical
effectiveness, harms, patient preference, and costeffectiveness.
A more precise estimate of the costeffectiveness
of chiropractic care for LBP relative to
other forms of conservative care is needed for decisionmakers
and third-party payers to offer best care options
for LBP. Evidence is also needed to help guide employer
and regulatory decisions to reduce unnecessary costs for
work-related LBP resulting in temporary or permanent
Search strategy for the review of clinical effectiveness
Search strategy for the review of economic evaluation
BMJ: British medical journal
CADTH: Canadian agency for drugs and
technologies in health
CIHI: Canadian institute for health information
CIHR: Canadian institute of health research
CPGs: Clinical practice guidelines
GDP: Gross domestic product
ICL: Index to chiropractic literature
LBP: Low back pain
NICE: National Institute for health and care excellence
PPP: Purchasing power parities
QALYs: Quality-adjusted life years
SMT: Spinal manipulative therapy.
Dr. Stochkendahl’s position is founded by the Danish Chiropractic Research
Foundation. Dr. Bussieres’s position at McGill University is funded by the
Canadian Chiropractic Research Foundation. The authors declare that they
have no competing interests.
MAB and AB conceived the idea for this study. JB and PH developed the
search strategy. MAB, AB, and MJS drafted this protocol. All authors commented
on the sequential drafts of the paper and agreed upon the final manuscript.
Dr. Blanchette is founded by a PhD fellowship granted by the Canadian
Institute of Health Research; Dr. Stochkendahl’s position is founded by the
Danish Chiropractic Research Foundation; Dr. Bussičres holds a Canadian
Chiropractic Research Foundation (CCRF) chair in Epidemiology and
Rehabilitation at McGill University; Ms. Boruff and Ms. Harrison received no
external funding. Participation in this work is paid by in kind contributions
from the authors’ respective funders and institutions.
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