What
is a reasonable conclusion?
You answered:
The
data strongly suggest efficacy, as the proportion of patients
improving is well above the usual 30% placebo response.
INCORRECT
In
fact, these data say little about efficacy of epidural steroids.
The common statement that one can expect 30% of patients
to get pain relief from a placebo is not correct (Turner
et al., 1994). The frequency of placebo effects
varies among analgesic studies from zero to more than 60%
(Turner
et al., 1994); Moore
et al, 1998. Efforts to identify and exclude "placebo
responders" from analgesic trials have not succeeded; given
repeated opportunities, most people will manifest a placebo
response.
Patients
in most chronic pain studies show some improvement, even
when treated with placebo. One cannot tell whether this
represents "regression to the mean" or placebo effect unless
one includes a no treatment group to compare to the group
given a placebo.
Comparison
to a placebo injection will let one infer how much of the
pain relief was due to the steroid and how much to the suggestive
value of the procedure.
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