A randomized, placebo-controlled clinical trial of chiropractic and medical prophylactic treatment of adults with tension-type headache: results from a stopped trial.

OBJECTIVES: 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.

METHODS: 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.

RESULTS: 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.

CONCLUSION: 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.