Dose-response of spinal manipulation for cervicogenic headache: Long-term outcomes from a randomized trial

Methods: 80 participants with chronic CHA were randomized to 4 groups: 2 levels of treatment dose and 2 levels of therapy. Patients received 8 treatments (1/wk) or 16 treatments (2/wk). The verum intervention was spinal manipulation provided by a DC; in preparation for manipulation, patients received light massage and a hot pack. The control group received a longer period of light massage and a hot pack, also provided by a chiropractor. Attention and expectation were controlled and treatment effects adjusted for baseline. The primary outcome was a 100-point pain scale.

Results: For 24-week pain, there was a clinically important main effect of treatment showing an advantage for spinal manipulation (Mdiff = 12.3, P = .018). There was no significant main effect of dose (Mdif = 0.4, P = .928) or treatment by dose interaction effect (P = .219). However, there was a 18.5-point advantage of manipulation over the control for 16 visits and only a 6.1-point difference for 8 visits. Secondary headache outcomes and outcomes for 16 and 20 weeks will also be presented.

Conclusions: This large pilot study supports the short-term efficacy of manipulation for the care of CHA across two doses of care: 8 and 16 treatment visits. There were no important main effects of treatment dose in the short term. However, the data suggest the possibility of a larger effect of manipulation relative to light massage at the higher dose (dose-response of treatment effect).

This research was supported by a grant from NCCAM/NIH (R21 AT002324).