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Dose response and efficacy of spinal manipulation for chronic cervicogenic headache: a pilot randomized controlled trial. Mitchell Hass, et al. IF: 3.024 . Introduction. CONSORT checklist results were good Headaches are a common pain condition
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Dose response and efficacy of spinal manipulation for chronic cervicogenic headache: a pilot randomized controlled trial Mitchell Hass, et al. IF: 3.024
Introduction • CONSORT checklist results were good • Headaches are a common pain condition • Cervicogenic headache (CGH) is within the top 3 headaches • Disabling: 157 million days lost from work • Costly: $50 billion • Management of CGH is common within chiropractic
Introduction • Evidence favors spinal manipulative therapy (SMT) for CGH, but is inconclusive • Evidence exists for reduction of CGH: • Intensity, frequency, and duration • Patient and SMT heterogeneity complicates previous findings • Unfortunately, the amount of treatment to obtain optimal outcomes has never been studied • Widely varied in research and practice
Introduction • Haas decided to investigate the optimal treatment duration and frequency • Began investigating the dose-response of SMT for CGH with a small (n=24) feasibility study, published in ’04 • Patients were allocated to 3, 12, or 16 visits over 3 weeks • Determined to be feasible to investigate the dose-response of SMT for the management of CGH • Preliminary data supported efficacy of 9-12 visits
Purpose • This article builds from the work from the previous feasibility study and investigates: • Dose: comparison of the effect of high dose (16 visits) vs. low dose (8 visits) of SMT for CGH pain intensity. • Efficacy: the relative efficacy of SMT for the care of CGH • Null hypothesis: no difference between SMT and Light Massage (LM). • Do you think these are worthy objectives for a study?
Methods • Pilot study • Randomized controlled trial • 80 participants • 2x2 Balanced Factorial design • Computer randomization was used to balance confounding baseline variables • Conducted at WSU and 3 Portland area private chiropractic clinics from 2004-07
Methods • 4 groups • All participants attended 16 visits over 8 weeks • Either 1x or 2x per week • Higher dose: 16 treatment visits • Lower dose: 8 treatments and 8 attention-control manual exams • All treatments lasted 10 minutes
Interventions • Providers: 4 DCs • SMT (therapeutic group): • 5 minutes of moist heat • 2 minutes of LM • Cervical and upper thoracic Diversified HVLA SMT • LM (control group): • 5 minutes of moist heat • 5 minutes of effleurage/pétrissage on neck and shoulders
1° Outcome • 1°: Modified Von Korff (MKV) pain intensity scale • CGH pain today, worst in past month, avg. last month • MCID = 20% of baseline pain • Powered to 80% (=0.05) to detect b/t group effect of 10 of 100 points • Not powered to detect interaction b/t intervention and dose. • Assessments performed each month for 6 months
2° Outcomes • MKV Disability scale • ADLs, social/recreational activities, and housework ability • Number of CGH • Number of other headaches • Rx medication use • OTC medication use • Supplement/botanical use for headaches • All treated as secondary analysis at =0.05
Statistical Analysis • Intention-to-treat analysis • Imputation for missing data • 1° outcome: Repeated Measures ANCOVA with GEEs • H0: means are the same at each time point • Adjusted group comparisons • Adjusted mean outcomes (AMD) • 2° outcomes: Multiple Logistic Regression • Outcome dichotomized to 50% improvement
Questions or comments • Advantages to the methods? • Limitations to the methods?
Sample • Younger (36 yrs), Caucasian (85%), females (80%) • 86% of visits were completed • Mean MKV Pain: 54/100 • Mean MKV Dysfunction: 45/100 • Avg. 4 CGHs per wk. • Approximately 90% thought they could discern their CGH form other types of headache
Results • 1° outcome: MVK Pain scale • Dose: no clinically important effects • Efficacy: clinical important and significant effects between groups, favoring SMT over LM • Most improvement was achieved at 8 weeks of care • Effects lasted through the end of the study (6 months) • Slightly larger effects for higher dose (16 visits)
LM 16 LM 8 SMT 8 SMT 16
Results • 2° outcomes • MVK Disability scale • Favored SMT (similar to MKV Pain scale results) • CGH and “other” headache frequency • Effect favored SMT • Medication use • Favored SMT – 1/3 fewer medications at end of study • 50% improvement in MKV Pain scale • Favored SMT - Adjusted OR 3.0
LM 16 LM 8 SMT 16 SMT 8
Discussion • Dose: • Little difference between high and low dose • Somewhat larger effects with higher dose (16 visits), but did not reach MCID • Efficacy: • Clinically important and statistically significant differences favoring the SMT group for CGH pain and dysfunction • SMT reduced the number of CGHs by ½ at 8 weeks • SMT was 3 times more likely to produce a 50% reduction of CGH pain
Limitations • Pilot study, low sample size – preliminary results • Patients and clinicians were not masked • Prevalence of migraine was unexpectedly low (28%) for patients suffering from CGHs • Medication use of the sample may not be generalizable because potential participants taking preventative analgesics were excluded from participation • Necessary to minimize confounding • Follow-up was limited by grant support
Conclusions • SMT is a viable option for the management of CGH • Pain • Headache frequency • Plateau in effects between 8 to 16 session • 12 week mark • Dose-response relationship remains unknown • Cost-effectiveness remains unknown
The next step… • NIH has awarded UWS $717,384 for Hass M, et al. to perform a follow-up study • Investigating the optimal dose of SMT for the management of CGH • Dose-response of SMT for CGH • Cost-effectiveness of care • 5-year multicenter randomized trial • 256 participants • Dose: 0, 6, 12, or 18 sessions for SMT or LM • 1° outcomes: CGH pain and number
Your opinions… • Were any of the results surprising? • What do the preliminary results from this study suggest for clinicians? • What do these results suggest about dose-response? • What do these results suggest concerning safety? • Additional limitations of this study?