The influence of clinical equipoise and patient preferences on outcomes of conservative manual interventions for spinal pain: an experimental study

Abstract

BackgroundExpected pain relief from treatment is associated with positive clinical outcomes in patients with musculoskeletal pain. Less studied is the influence on outcomes related to the preference of patients and providers for a specific treatment.ObjectivesWe sought to determine how provider and patient preferences for a manual therapy intervention influenced outcomes in individuals with acutely induced low back pain (LBP).Participants and methodsPain-free participants were randomly assigned to one of two manual therapies (joint biased [JB] or constant touch [CT]) 48 hours after completing an exercise protocol to induce LBP. Expectations for pain relief and preferences for treatment were collected at baseline, prior to randomization. Pain relief was assessed using a 100 mm visual analog scale. All study procedures were conducted in a private testing laboratory at the University of Florida campus.ResultsSixty participants were included in this study. After controlling for preintervention pain intensity, the multivariate model included only preintervention pain (B=0.12, p=0.07) and provider preference (B=3.05, p<0.0001) and explained 35.8% of the variance in postintervention pain. When determining whether a participant met his or her expected pain relief, receiving an intervention from a provider with a strong preference for that intervention increased the odds of meeting a participant’s expected pain relief 68.3 times (p=0.013) compared to receiving any intervention from a provider with no preference. Receiving JB intervention from any provider increased the odds of meeting expected relief 29.7 times (p=0.023). The effect of a participant receiving an intervention they preferred was retained in the model but did not meet the criteria for a significant contribution.ConclusionOur primary findings were that participant and provider preferences for treatment positively influence pain outcomes in individuals with acutely induced LBP, and joint-biased interventions resulted in a greater chance of meeting participants’ expected outcomes. This is contrary to our hypothesis that the interaction of receiving an intervention for which a participant had a preference would result in the best outcome.

Immediate effects of cervical mobilisations on global perceived effect, movement associated pain and neck kinematics in patients with non-specific neck pain. A double blind placebo randomised controlled trial

“…This study was not powered to perform a secondary analysis of outcome predictor variables and therefore conclusions regarding predictors must be considered with caution. Therapist´s treatment preferences have been found to affect treatment outcome 78 and we were unable to control for this, which may have favoured a better outcome in the mobilisations group. We used manual contact to assess the placebo effect, however touch has been found to have an analgesic effect by a gating of the ascending nociceptive afferent input at subcortical level, especially if the area of stimulation is close to the source of pain 79 .…”

Five good reasons to be disappointed with randomized trials

“…Personal equipoise toward a particular intervention will unconsciously cause an improve outcome for the treatment of preference. For example, in randomized trials where clinicians preferred a particular treatment approach (despite being randomized between two groups), the preference influenced outcomes in a way that supported their preference [27,28].…”

An empirical, pragmatic approach applying reflection in interaction approach to manual therapy treatments

“…Many of these studies considered physiological responses to treatment in either asymptomatic or symptomatic individuals. The relationship, however, is tenuous between such physiological changes and a potential therapeutic response (Bishop et al, 2017).…”