Validation of Placebo in a Manual Therapy Randomized Controlled Trial

Abstract

At present, no consensus exists among clinical and academic experts regarding an appropriate placebo for randomized controlled trials (RCTs) of spinal manipulative therapy (SMT). Therefore, we investigated whether it was possible to conduct a chiropractic manual-therapy RCT with placebo. Seventy migraineurs were randomized to a single-blinded placebo-controlled clinical trial that consisted of 12 treatment sessions over 3 months. The participants were randomized to chiropractic SMT or placebo (sham manipulation). After each session, the participants were surveyed on whether they thought they had undergone active treatment (“yes” or “no”) and how strongly they believed that active treatment was received (numeric rating scale 0–10). The outcome measures included the rate of successful blinding and the certitude of the participants’ beliefs in both treatment groups. At each treatment session, more than 80% of the participants believed that they had undergone active treatment, regardless of group allocation. The odds ratio for believing that active treatment was received was >10 for all treatment sessions in both groups (all p < 0.001). The blinding was maintained throughout the RCT. Our results strongly demonstrate that it is possible to conduct a single-blinded manual-therapy RCT with placebo and to maintain the blinding throughout 12 treatment sessions given over 3 months.

What is the effect of spinal manipulation on the pressure pain threshold in young, asymptomatic subjects? A randomized placebo-controlled trial, with a cross-over design

“…None of these sham interventions were validated after intervention. A major difference with other studies was, therefore, that our trial used a previously validated sham procedure that imitated a proper SM in all aspects expect in the area and direction of the thrust, as it was performed over the scapula in the plane of the thoracic cage [10]. Very importantly, we also confirmed with a post-intervention questionnaire, if study subjects had identified the 'effective' intervention from the 'ineffective' intervention, which they had not.…”

“…It was validated immediately after each of 12 treatment sessions over 3 months by post-treatment questionnaires with more than 80% of success (i.e. more than 80% of the subjects did not spot the difference between a "real" intervention and the sham intervention) [10]. Previously, it has been unusual that researchers check whether the sham intervention was recognized as such, or whether study subjects were 'fooled' by the procedure.…”

“…We selected this method to confuse the study subjects, who had been told that they would be subjected to different manipulative techniques. An almost identical version of this method has been previously validated with good results [10].…”

Manual therapy as an effective treatment for fibrosis in a rat model of upper extremity overuse injury

“…It seems likely that the fibrosis affecting the median nerve and its branches could be key to the pathophysiology in this model by induction of a persistent nerve inflammation and compressive pathology. Because we do not know which modality was effective, and because clinical manual therapy research is plagued by lack of consensus regarding sham treatments (Chaibi, Saltyte Benth et al 2015), we chose to have a control group that was held only, and not otherwise actively treated. Further research is planned to address these challenging questions, as well as possible changes in angiogenesis and vascular function reported to occur with massage therapy (Andrzejewski, Kassolik et al 2014, Franklin, Ali et al 2014, Andrzejewski, Kassolik et al 2015).…”

Immediate effects of cervical unilateral anterior-posterior mobilisation on shoulder pain and impairment in post-operative arthroscopy patients

“…However, we consider the selection the best choice for comparisons to a Grade III mobilisation where range of accessory motion and more substantial tissue pressure represent the most probable influences for neurophysiological and mechanistic treatment effect. Additionally, the positive effects of 'being touched' [50,51] are accounted for. Fourth, the primary advantages of a crossover design are that smaller sample sizes are necessary, that subjects act as their own control, and that within-subject variability is generally assumed to be smaller than between-subject variability seen in parallel designs.…”