Background Context
The optimal number of visits for the care of cervicogenic headache
(CGH) with spinal manipulative therapy (SMT) is unknown.
Purpose
To identify the dose-response relationship between visits for SMT and
chronic CGH outcomes; to evaluate the efficacy of SMT by comparison with a
light massage control.
Study Design/Setting
Two-site, open-label randomized controlled trial.
Patient Sample
Participants were 256 adults with chronic CGH.
Outcome Measures
The primary outcome was days with CGH in the prior 4 weeks evaluated
at the 12- and 24-week primary endpoints. Secondary outcomes included CGH
days at remaining endpoints, pain intensity, disability, perceived
improvement, medication use, and patient satisfaction.
Methods
Participants were randomized to 4 dose levels of chiropractic SMT: 0,
6, 12, or 18 sessions. They were treated 3 times per week for 6 weeks and
received a focused light-massage control at sessions when SMT was not
assigned. Linear dose effects and comparisons to the no-manipulation control
group were evaluated at 6, 12, 24, 39, and 52 weeks. This study was funded
by the National Center for Complementary and Integrative Health
(R01AT006330) and is registered at ClinicalTrials.gov
(NCT01530321). The authors declare no conflicts of interest.
Results
A linear dose-response was observed for all follow-ups, a reduction
of approximately 1 CGH day/4 weeks per additional 6 SMT visits
(p<.05); a maximal effective dose could not be determined. CGH
days/4 weeks were reduced from about 16 to 8 for the highest and most
effective dose of 18 SMT visits. Mean differences in CGH days/4 weeks
between 18 SMT visits and control were -3.3 (p=.004) and -2.9
(p=.017) at the primary endpoints, and similar in magnitude at the
remaining endpoints (p<.05). Differences between other SMT doses and
control were smaller in magnitude (p > .05). CGH intensity showed no
important improvement nor differed by dose. Other secondary outcomes were
generally supportive of the primary.
Conclusion
There was a linear dose-response relationship between SMT visits and
days with CGH. For the highest and most effective dose of 18 SMT visits, CGH
days were reduced by half, and about 3 more days per month than for the
light-massage control.