Tension-type headache (TTH) is the most common headache experienced by adults in Western
society. Only 2 clinical trials of spinal manipulation for adult tension-type headache
have been reported, neither of which was fully controlled. In 1 trial, spinal manipulation
was compared to amitriptyline. There is an urgent need for well-controlled studies
of chiropractic spinal manipulation for TTH. This trial was stopped prematurely due
to poor recruitment. The purposes of this report are (1) to describe the trial protocol,
as it contained several novel features, (2) to report the limited data set obtained
from our sample of completed subjects, and (3) to discuss the problems that were encountered
in conducting this study.
A randomized clinical trial was conducted with a factorial design in which adult TTH
sufferers with more than 10 headaches per month were randomly assigned to four groups:
real cervical manipulation + real amitriptyline, real cervical manipulation + placebo
amitriptyline, sham cervical manipulation + real amitriptyline, and sham cervical
manipulation + placebo amitriptyline. A baseline period of four weeks was followed
by a treatment period of 14 weeks. The primary outcome was headache frequency obtained
from a headache diary in the last 28 days of the treatment period.
Nineteen subjects completed the trial. In the unadjusted analysis, a statistically
significant main effect of chiropractic treatment was obtained (-2.2 [-10.2 to 5.8],
P = .03) which was just below the 3-day reduction set for clinical importance. As
well, a clinically important [corrected] effect of the combined therapies was obtained
(-9 [-20.8 [corrected] to 2.9], P = .13), but this did not achieve statistical significance.
In the adjusted analysis, neither the main effects of chiropractic nor amitriptyline
were statistically significant or clinically important; however, the effect of the
combined treatments was -8.4 (-15.8 to -1.1) which was statistically significant (P
= .03) and reached our criterion for clinical importance.
Although the sample size was smaller than initially required, a statistically significant
and clinically important effect was obtained for the combined treatment group. There
are considerable difficulties with recruitment of subjects in such a trial. This trial
should be replicated with a larger sample.