J Altern Complement Med 2002; 8 (1) Feb: 21–32 ~ FULL TEXT
Hawk C, Long CR, Reiter R, Davis CS, Cambron JA, Evans R
Palmer Center for Chiropractic Research,
Davenport, IA 52803, USA.
OBJECTIVE: There are fundamental differences between the administration of medications and the application of manual procedures, such as those used by chiropractors. The objective of this study was to gather preliminary information on how to address these differences in the design of a multisite, randomized placebo-controlled trial of chiropractic care for women with chronic pelvic pain (CPP).
DESIGN: Pilot study for a multisite, randomized, placebo-controlled clinical trial.
SETTING: Three chiropractic research clinics in the midwest United States.
Thirty-nine (39) women with CPP of at least 6 months' duration, diagnosed by board-certified gynecologists.
INTERVENTIONS: The active intervention consisted of the chiropractic technique, lumbar spine flexion-distraction, combined with manual Trigger Point Therapy. The placebo intervention consisted of a sham chiropractic procedure performed with an instrument combined with effleurage (light massage).
OUTCOME MEASURES: The primary outcome measure was the change in the Pain Disability Index (PDI) from baseline to the end of treatment (6 weeks), assessed by group and site. If the change score was in the same direction at all sites, the results were to be combined to estimate treatment effect size.
RESULTS: Patient characteristics were similar to those of patients with CPP in other studies. Recruitment methods, particularly in respect to the eligibility criteria and screening protocols, would require modification in order to recruit an adequate sample for the planned randomized controlled trial. Clinicians followed standardized procedures with apparently minimal deviation, patients in both groups were satisfied with their care and blinding appeared to be successful. PDI change scores were not consistent across sites and so results were not combined and overall treatment effect sizes were not estimated.
CONCLUSION: The technical and personnel resources required to achieve adequate standardization of procedures at multiple sites may make a placebo-controlled trial unfeasible, given our current lack of knowledge about the active agent in manual chiropractic procedures.
From the FULL TEXT Article:
This was a pilot study; it was not designed
to investigate the efficacy of chiropractic care
for symptoms of CPP. It was designed to provide
the investigators with information on
whether it is feasible to move forward with
plans for an RCT on that topic.
Comparing this study to our previous singlegroup
study (Hawk et al., 1997), baseline PDI
scores and symptomatology were similar. Antidepressant
use in this study compared to the
earlier one was also similar, whereas hormone
use was considerably less (15% versus 37%), with prescription analgesic use (10% versus
5%) and nonprescription analgesic use (54%
versus 63%) being not too dissimilar. Baseline
depression as measured by the BDI was in the
mild category for this study and moderate for
the previous one.
Compared to characteristics of patients in
studies of medical care for women with CPP,
our patients were in the same age range and
were similar in terms of low-back pain and dysmenorrhea,
but there appeared to be fewer
with a history of sexual/physical abuse (Peters
et al., 1991; Reiter, 1990; Reiter and Gambone,
1990; Reiter & Milburn, 1992). Patients in our
study did not report much use of supplements
or herbs. It is possible that patients interested
in CAM therapies were screened out because
of the exclusion of those with recent chiropractic
experience. Generally, it appears that
our patients were fairly similar to those in our
previous study and to medical CPP patients.
It appears that we cannot recruit enough patients
for a larger study using this study’s parameters,
particularly in respect to the eligibility
criteria and screening protocols. Further
study is needed on the necessity of excluding
patients with recent chiropractic experience.
Also, exploration of methods to expedite the
screening process and develop referral relationships
with local gynecologists is warranted.
Delivery of standardized procedures and record keeping of procedures used
The chiropractic clinicians followed strict
protocols for delivering standardized procedures
without a great deal of variation and
maintained more detailed records about specific
treatment procedures than are often required
in clinical studies, facilitating in-depth
analysis. Even though no differences were
noted in patient satisfaction or perception of
group assignment, patients did note differences
between clinicians’ treatments, usually in
the case where there were large differences in
the experience level of the clinicians. Because
outcomes were ambiguous, it behooves us to
develop better ways for future multisite studies
to ensure that clinicians are actually delivering the same procedures in terms of biomechanical
forces and techniques.
Identity of the active agent
One would expect the active group to show
greater improvement than the placebo group,
if the procedures used were, in fact, “active”
and “placebo” agents. However, this pattern
was only discernable at site 1, where the primary
clinician was the most highly experienced
in this technique but also was the only one who
varied the active procedure in response to individual
patient needs. At site 2, patients in
both groups improved approximately equally,
and at site 3, it appeared that patients in the
placebo group improved more, although the
sample sizes were extremely small. These ambiguous
results indicate a need to ensure that
the active and placebo procedures are applied
according to strict biomechanical parameters in
a multisite study, in order to eliminate variation
introduced by use of different clinicians.
Success of blinding
From patient report of satisfaction with the
intervention and belief about group assignment,
the placebo intervention was believable.
The question that must be answered before
conducting a placebo-controlled trial, however,
is related to the issue of the identity of the active
agent: Was the placebo intervention, in
fact, a placebo? Further investigation of the biomechanical
forces producing treatment effects
is certainly warranted.
The technical and personnel resources required
to achieve adequate standardization of
procedures at multiple sites may make a
placebo-controlled trial unfeasible, given our
current lack of knowledge about the active
agent in manual chiropractic procedures. It
might be more efficient to reverse the traditional
order of experimentation used for pharmaceuticals,
which begins with safety, proceeds
to efficacy and finally to effectiveness.
Because chiropractic—a CAM profession using
manual methods for more than 100 years—can
scarcely be considered in the same category as
a newly developed medication, it might be reasonable
to first investigate effectiveness. If chiropractic
care that is provided by experienced
chiropractors who are allowed to use their best
clinical judgment of how to apply the procedures
is documented in such studies to improve
patient outcomes compared to standard
medical care alone, more in-depth and controlled
studies would then be warranted to
identify specific aspects of that gestalt of care
that are most responsible for the outcomes or
if there are certain subpopulations of patients
who benefit most from them.