1 Dose-Response of Spinal Manipulation for Cervicogenic Headache: Long-Term Outcomes from a Randomized Trial Mitchell Haas, DC, MA 1 Adele Spegman, PhD, RN 1, 3 Dave Peterson, DC 1 Mikel Aickin, PhD 2 Bonnie Ganger 1 1. Western States Chiropractic College, Portland, Oregon, USA 2. University of Arizona, Tuscan, Arizona, USA 3. Geisinger Center for Health Research Funded by: NCCAM / NIH (R21 AT002324)

2 METHODS

3 Methods  Pilot study – make preliminary estimates of:  Effect of SMT dose on outcomes.  Efficacy of SMT across dose.  2-way factorial design:  Dose: 8 or 16 treatments.  Treatment: SMT or light massage therapy (MT).  80 participants randomized to 4 groups (n = 20):  Design adaptive allocation to balance 7 variables.  pain, # HA, migraines, age, gender, confidence in tx success, optimal # tx.  16 visits in 8 weeks (2 per wk):  Intervention visit: hot pack, muscle prep, & SMT or MT.  Attention control exam: ROM, pain threshold, & joint restriction. Dose Tx 8x16x MT20 SMT20

4 Methods  Outcomes:  CHA pain & disability (100-pt MVK scales).  # CHA & # disability days.  Neck pain & disability (100-pt MVK scales).  Primary outcome: CHA pain at 12 weeks.  Data collection: 0, 4, 8, 12, 16, 20, & 24 weeks.  Analysis:  Simultaneous Regression: 7 Baseline covariates used in allocation algorithm. Missing data imputed.  Power: 80% to detect 10-point main effect in CHA pain.  Significance: alpha =.05

5 RESULTS

6 Not eligible = 8 Not interested = 4 Not eligible = 200 Not interested = 51 Exam no show = 3 Randomization (n = 80) Follow-up 2 wk = 19 4 wk = 15 8 wk = wk = wk = wk = wk = 17 Follow-up 2 wk = 19 4 wk = 17 8 wk = wk = wk = wk = wk = 18 Follow-up 2 wk = 19 4 wk = 20 8 wk = wk = wk = wk = wk = 19 Phone Screen (n = 354) Baseline Exams (n = 92) Follow-up 2 wk = 20 4 wk = 16 8 wk = wk = wk = wk = wk = 18 ≥ 2/3 visits n = 16 (80%) ≥ 2/3 visits n = 18 (90%) ≥ 2/3 visits n = 16 (80%) ≥ 2/3 visits n = 15 (75%) 8 SMT + 8 exam (n = 20) 16 SMT (n = 20) 8 MT + 8 exam (n = 20) 16 MT (n = 20)

7 Baseline Characteristics 8 SMT16 SMT8 MT16 MTAll Age Female80% 75%85%80% White, non-Hispanic100%90%60%90%85% Married or Equivalent50% 35%46% College degree40%50%45%60%49% Income: < $24,000/year30%35% 40%35% Back pain problem50%55%50%40%49% Any co-morbidity75%65% 60%66% SF-12 Physical (PCS) SF-12v2 Mental (MCS)

8 Baseline HA Condition Characteristics 8 SMT16 SMT8 MT16 MTAll CHA Pain CHA Disability # CHAs (last 4 wks)1516 # CHA disability days53575 Neck Pain Neck Disability Migraine Sufferer70% 75 %70 %71%

9 Compliance: Any Care During Tx Phase

10 Pain Outcomes

11 Pain Outcomes (factorial model) P12w24w Tx dose inter

12 Advantage of 16 visits over 8 visits for Pain: Adjusted Main Effect of Dose (mean difference)

13 Advantage of SMT over MT for Pain: Adjusted Main Effect of Tx (mean difference)

14 Pain Outcomes (additive model) P12w24w Tx dose

15 Clinical Benefit: Predicted Pain Improvement at 12 weeks M 8 MT 9 16 MT 10 8 SMT SMT 20

16 Disability Outcomes P12w24w Tx dose

17 # Cervicogenic Headaches - Last 4 wk P12w24w Tx dose

18 Clinical Benefit: Predicted Improvement in # CHA M 8 MT 6 16 MT 4 8 SMT SMT 8

19 # Disability Days - Last 4 wk P12w24w Tx dose

20 Neck Pain P12w24w Tx dose

21 Neck Disability P12w24w Tx dose

22 SUMMARY

23 Conclusions  Efficacy: Preliminary evidence that SMT is superior to light massage for CHA pain at the treatment doses studied. SMT is promising for disability, # HA & disability frequency.  Dose: Preliminary evidence that 16 SMT treatments is no better than 8 treatments (saturation of effect). But…  Interaction: For pain, there is the possibility of a modest dose-response for SMT & a trend in tx effect across dose (dose-tx effect).  Time Trend: Sustained effect of SMT to 24 weeks. Room for further improvement.

24 Thank You! I Think, Sort Of Therefore I am, Maybe! Mitch ?