Objectives: Determining efficacy in complementary medicine research requires valid placebo/sham control groups that are credible to patients and ensure successful blinding. Within the scope of this study, a light touch sham-control intervention for trials of Craniosacral Therapy (CST) was developed and tested for its credibility.
Methods: Patients of a randomized controlled trial on chronic non-specific neck pain (NCT01526447) obtained the Credibility/Expectancy Questionnaire and the Helping Alliance/Satisfaction Questionnaire. Treatment and sham group respectively received 8 weekly sessions of CST or light touch. Data without (N=50) and with multiple imputation (N=54) were analyzed separately using logistic regression models. Adjusted odds ratios (AOR) and 95% confidence intervals (CI) were calculated to assess whether group outcome could be predicted from patients' credibility ratings. An additional t-test for analysis of the overall compliance/attendance was conducted.
Results: Patients' ratings of treatment expectancy, credibility and therapeutic alliance were not found to have significant power for classifying patients into CST or sham group (p≥.05). Only satisfaction with treatment revealed a significant impact (AOR: 6.83; 95% CI: [1.54|30.24]; p=.011) in the non-imputed analysis, but not in the multiple imputation analysis (AOR: 4.09; 95% CI: [0.94|17.76]; p=.060). Compliance of both groups was not significantly different (p>.05) as were reasons for non-attendance. No serious adverse events were reported.
Conclusions: Patients' expectancy, credibility and therapeutic alliance did not appear to affect study outcomes, blinding patients to group allocation was possible, and sham intervention was tolerable and safe. The design can therefore be recommended as control for non-specific treatment effects in future CST clinical trials.
Keywords: Blinding success; Craniosacral therapy; Placebo effect; Sham procedure; Treatment credibility.
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