Randomised Controlled Trials
(RCTs)
7.12 An RCT is a trial with two defining features.
First, control: outcomes for patients in the trial are compared
with outcomes for patients in a "control" group who
do not receive the treatment. Second, randomness: patients are
assigned to the two groups at random, so that any difference in
outcome can be attributed solely to the treatment.
7.13 The control population in an RCT can either
consist of patients with the same pathology who receive a "dummy"
(or placebo) treatment (to test overall efficacy) or a group who
receive a comparison treatment to assess whether the therapy under
investigation has any advantages in terms of efficacy, safety,
cost or other benefits. Where the most important question is whether
the effect is psychological, it is crucial to have a placebo control
group who believe they are receiving the treatment when in fact
they are not. (This is a "blind" trial).
7.14 Much of our evidence states that the RCT is
regarded as the most powerful scientific tool for evaluating medical
therapies and is accepted as the gold standard in research against
which to assess a therapy's efficacy.
7.15 Although many scientists see RCTs as the ultimate
analytical tool, RCTs may not fully embrace the CAM paradigm.
Some CAM practitioners suggest that RCTs cannot do justice to
the individualised, person-centred approach of many CAM therapies.
7.16 FIM explained some of the reasoning behind such
claims: "In particular two things are really important in
many CAM therapies. Firstly, the idea of standardisation versus
individualisation, that actually individualised treatment has
a higher value than a standard treatment, and standardising CAM
treatments can lead to research outcomes which are not true of
the therapy. The second point is that the traditional diagnoses
which are used or the hands-on skill…are incredibly important
in ensuring a good outcome, and that too has to be taken into
account when you look at research" (Q 91).
7.17 The Aromatherapy Organisations Council also
explained why they do not believe RCTs are always the appropriate
method for CAM research: "It is not necessarily appropriate
for all medical and healthcare interventions to be backed by the
evidence of controlled clinical trials and by conventional scientific
thinking. As Kleijnen[47]
points out: 'the healing process is traditionally in three parts:
the self-healing properties of the body; the changes induced by
non-specific effects of the therapist and the setting in which
the therapy takes place; and specific effects of physical and
pharmacological interventions.' In mainstream medicine, the latter
usually predominates (but not always) while in complementary medicine
it is the second mechanism, and the first process is invariably
a factor in both cases. The second may be considered a placebo
response and this has made the conducting of randomised controlled
trials in aromatherapy difficult" (p 14).
7.18 In March 2000 we visited the Marylebone Health
Centre (see Appendix 4) which conducts practice-based research.
During our visit, Dr David Peters, a GP and osteopath, discussed
the applicability of research to real-life practice. He suggested
that although RCTs and meta-analysis of RCTs are valuable, in
that they provide certainty about the efficacy of a medication
for a particular condition, real-life primary care does not mirror
the way illness and treatment are defined in such research. He
further explained that many patients do not come to their practitioners
with specific, well-defined conditions, but the conditions of
entry into most trials eliminates all but the most clear-cut examples
of a condition. He suggested that this is especially a problem
for CAM as GPs often refer the more complicated patients with
chronic, complex conditions to CAM practitioners. Often these
patients were not suffering from a single problem; although a
particular condition may have been the primary reason for referral,
further discussion often unveiled an array of inter-related problems.
Thus, the simple definitions of clinical problem and treatment
that good RCTs require do not always mirror the complexity of
CAM practice.
7.19 Many conventional researchers and medical practitioners
have criticised the arguments CAM practitioners use against RCTs,
and have suggested that they are just excuses to avoid having
to submit a type of therapy to scientific scrutiny. Professor
Tom Meade of the Royal Society told us: "I do not see any
reason why any of those CAMs cannot be subjected to randomised
control trials. There is absolutely nothing different, in principle,
between a CAM and a conventional treatment. A lot of …CAMs
have actually already been subjected to randomised control trials"
(Q 163). Dr Stephen Straus concurred with Professor Meade's opinion:
"The tools of science are such that they can be brought to
bear on this field. There is often the prejudice that the tools
of science have nothing to add to the field of complementary and
alternative medicine. I respectfully disagree with that opinion"
(Q 1733).
7.20 Despite accounts that only a few years ago no
middle ground could be found between those who rejected RCTs as
a research method for CAM and those who advocated them as the
only way to prove a therapy's efficacy, we found a growing acceptance
from all sides that RCTs had their place but that that place was
alongside other research methodologies. Therefore evidence from
RCTs must be seen in the context of other evidence from different
sources. For example the British Acupuncture Council wrote that:
"When researching the evidence for acupuncture, different
research questions require different methodologies. To answer
questions of efficacy, effectiveness and cost effectiveness, the
randomised control trial (RCT) will provide the most vigorous
evidence. However where RCTs are too difficult, non-randomised
controlled studies, outcome studies and observational studies
may provide the best evidence. The variety of research methods
range from quantitative to qualitative, and often these two approaches,
when appropriately combined, provide triangulation which strengthens
the evidence base" (p 28).
7.21 The Academy of Medical Sciences agreed: "…all
medical and healthcare interventions should ideally be backed
by the evidence of controlled clinical trials and by scientific
thinking…evaluation cannot, however, always be achieved by
double-blind trial but requires a synthesis of evidence from every
reliable source" (p 3).
7.22 It has been suggested that one of the reasons
many CAM practitioners are so suspicious of the RCT is because
of a widespread perception of the rigidity of such trials and
a lack of understanding that their design can be somewhat flexible.
For example, not everyone realises that RCTs do not invariably
have to be blinded or fully standardised[48]
in the way many imagine. Professor Tom Meade described how RCTs
can be adapted for different treatments: "Many of them, of
course, cannot be double- or single-blind (see para 3.30); the
patient and the therapist are both going to know what treatment
is being given. There are ways of getting round that. For example,
the patient can be asked to go to an assessor who does not know
what treatment he or she was having, and in my experience patients
enjoy that; they rather like the air of mystery and slight deception
that is involved in that. It works very well…I think the
point that you make about the amount of treatment varying in some
circumstances is not, again, in principle, any different from
conventional medicine, and what you may be saying there is that
you are testing a package of treatment against some other treatment
and you are not necessarily concerned, at that stage, with the
dosage effect; you are just wanting to see if patients who have
had this treatment, devised according to whatever the therapist
thinks is best, will do better than patients who are given another
treatment" (Q 163).
7.23 The RCCM confirmed that there is often misunderstanding
among proponents of CAM concerning the flexibility of the RCT:
"I think from the point of view of CAMs there is, to some
extent, a misunderstanding about the nature of the RCT and the
fact that perhaps it needs to be blinded, and it does not; it
is possible to carry out randomised control trials that are unblinded.
There is a question of what is a comparable or useful control
because, for example, it is very difficult to find a believable
placebo for acupuncture. Various researchers have tried it but
it is very difficult to find one. However, what is possible to
do is to carry out pragmatic randomised control trials; for example,
to randomise patients with a particular problem — chronic
back pain for example — into a group where they
receive a holistic assessment from a traditional Chinese acupuncturist
and then receive individualised care. This group of patients is
compared with the best available treatment we have" (Q 129).
7.24 It is clear that, in the treatment of many conditions
which are not life-threatening; sequential, longitudinal or cross-over
trials (with an intervening 'wash out' period) in which a conventional
medicine is given for a period, followed by a CAM therapy, or
vice-versa, are powerful and scientifically acceptable methods
for assessing the efficacy of a particular treatment. Alternatively,
the results of the best-known conventional treatment can be compared
with those of a CAM therapy in matched groups of patients.
7.25 Concerns over RCTs distorting a therapy or disguising
its efficacy are not the unique concerns of CAM practitioners,
there are many potential problems for all therapies when designing
an RCT, and these are reviewed in Appendix 1. However, Vincent
& Furnham acknowledge that some of these methodological problems
are particularly pertinent to CAM research: these are elaborated
upon in Box 9.