Blinding and sham control methods in trials of physical, psychological, and self-management interventions for pain (article I): a systematic review and description of methods

How initial perceptions of the effectiveness of mind and body complementary and integrative health therapies influence long-term adherence in a pragmatic trial

OBJECTIVE

Beliefs and perceptions about pain intervention effectiveness when initiating a therapy may influence long-term engagement. This study examines how early perceived effectiveness of complementary and integrative health therapies impacts long-term engagement in a pragmatic trial context.

PARTICIPANTS

Veterans with chronic musculoskeletal pain participating in a pragmatic trial of provider-delivered complementary and integrative health therapies (acupuncture, chiropractic care, or massage therapy) used alone compared to combining those therapies with self-care therapies (yoga, Tai Chi/Qigong, or meditation). This analysis focuses on 1713 participants using self-care therapies at baseline.

SETTING

18 Veterans Healthcare Administration Medical Facilities.

DESIGN

Prospective cohort study.

METHODS

Predictors of total self-care complementary and integrative health therapy sessions over a 6-month assessment period were assessed using linear regression to determine how strongly perceptions of initial therapy effectiveness was associated with total utilization. Perception of initial therapy effectiveness was assessed at study entry across four domains (pain, mental health, fatigue, and general well-being).

RESULTS

In total, 56% (1032/1713) of Veterans reported a positive perceived effectiveness of their recent complementary and integrative health therapy use at study initiation. Older individuals and those using meditation were more likely to report early positive perceptions. Mean number of therapy sessions over the 6-month study was 11 (range 1 to 168). Early positive perceptions had a small effect on overall use, increasing mean sessions by 2.5 (1.3 to 3.6). Other factors such as recent physical therapy use and distance to primary care explained more variation in total utilization.

CONCLUSIONS

Pragmatic pain trials should examine factors associated with engagement across assigned treatment protocols, especially if any of the treatment protocols being tested are sensitive to long-term engagement.

Pain, mindfulness, and placebo: a systematic review

Introduction

Pain is a complex phenomenon influenced by psychosocial variables, including the placebo effect. The effectiveness of mindfulness-based interventions (MBIs) for pain has been demonstrated in experimental studies and systematic reviews, but the mechanisms of action are only starting to be established. Whether the expectations of individuals experiencing pain can be manipulated during MBIs remains to be systematically evaluated, and what role placebo effects might play remains to be explored.

Methods

To evaluate the literature analyzing placebo effects in MBIs for pain, we performed a systematic review based on searches conducted in PubMed, Web of Science, and SCOPUS databases. Our search revealed a total of 272 studies, of which only 19 studies were included (10 acute pain and nine chronic pain), considering the inclusion and exclusion criteria related to expectations and placebo effects.

Results

From the 19 included studies, six measured placebo effects only in relation to the pharmacological intervention used in the study and not to an MBI.

Discussion

The results of the few studies that focused on the placebo effects of the MBIs indicate that placebo and expectations play a role in the MBIs' effects on pain. Although expectations and placebo effects are frequently discussed in the context of mindfulness and pain research, these results show that these factors are still not routinely considered in experimental designs. However, the results of the few studies included in this systematic review highlight a clear role for placebo and expectancy effects in the overall effects of MBIs for both acute and chronic pain, suggesting that routine measurement and further consideration in future studies are warranted. Additional research in this fascinating and challenging field is necessary to fully understand the connection between MBIs, placebo/expectations, and their effects on pain relief.

The Efficacy of Neuromodulation Interventions for Chemotherapy-Induced Peripheral Neuropathy: A Systematic Review and Meta-Analysis

Purpose

To determine the efficacy and safety of a neuromodulation intervention regimen in the treatment of chemotherapy-induced peripheral neuropathy (CIPN).

Patients and Methods

Systematic searches were conducted in seven English databases. Randomized controlled trials of all neuromodulation interventions (both invasive and non-invasive) for the treatment of CIPN were selected. Group comparisons of differences between interventions and controls were also made. We divided the outcomes into immediate-term effect (≤3 weeks), short-term effect (3 weeks to ≤3 months), and long-term effect (>3 months).

Results

Sixteen studies and 946 patients with CIPN were included. Among immediate-term effects, neuromodulation interventions were superior to usual care for improving pain (SMD=-0.77, 95% CI -1.07~ 0.47), FACT-Ntx (MD = 5.35, 95% CI 2.84~ 7.87), and QOL (SMD = 0.44, 95% CI 0.09~ 0.79) (moderate certainty); neuromodulation loaded with usual care was superior to usual care for improving pain (SMD=-0.47, 95% CI -0.71 ~ -0.23), and QOL (SMD = 0.40, 95% CI 0.12 ~ 0.69) (moderate certainty). There were no statistically significant differences between the neuromodulation interventions regimen vs usual care in short- and long-term outcomes and neuromodulation vs sham stimulation from any outcome measure. There were mild adverse events such as pain at the site of stimulation and bruising, and no serious adverse events were reported.

Conclusion

Neuromodulation interventions had significant immediate-term efficacy in CIPN but had not been shown to be superior to sham stimulation; short-term and long-term efficacy could not be determined because there were too few original RCTs. Moreover, there are no serious adverse effects of this therapy.

Virtually delivered Mindfulness-Oriented Recovery Enhancement (MORE) reduces daily pain intensity in patients with lumbosacral radiculopathy: a randomized controlled trial

Introduction

Lumbosacral radiculopathy (LR), also known as sciatica, is a common type of radiating neurologic pain involving burning, tingling, and numbness in the lower extremities. It has an estimated lifetime prevalence as high as 43%.

Objectives

The objective of this randomized controlled trial was to evaluate the impact of virtually delivered Mindfulness-Oriented Recovery Enhancement (MORE) on patients with LR during the COVID-19 pandemic.

Methods

Potentially eligible patients were identified using electronic health record queries and phone screenings. Participants were then randomized to MORE or treatment-as-usual (TAU) for 8 weeks, with pain intensity assessed daily. At baseline and follow-up visits, participants completed questionnaires assessing the primary outcome, disability, as well as quality of life, depression, mindful reinterpretation of pain, and trait mindfulness.

Results

In our study, patients undergoing virtual delivery of MORE had greater improvements in daily pain intensity (P = 0.002) but not in disability (P = 0.09), depression (P = 0.26), or quality of life (P = 0.99 and P = 0.89, SF-12 physical and mental component scores, respectively), relative to TAU patients. In addition, patients in MORE experienced significantly greater increases in mindful reinterpretation of pain (P = 0.029) and trait mindfulness (P = 0.035).

Conclusion

Among patients with lumbar radiculopathy, MORE significantly reduced daily pain intensity but did not decrease disability or depression symptoms. Given the long duration of symptoms in our sample, we hypothesize the discrepancy between changes in daily pain intensity and disability is due to fear avoidance behaviors common in patients with chronic pain. As the first trial of a mindfulness intervention in patients with LR, these findings should inform future integrative approaches to LR treatment, particularly when considering the increasing use of virtual interventions throughout the COVID-19 pandemic.

Placebo analgesia in physical and psychological interventions: Systematic review and meta-analysis of three-armed trials

BACKGROUND

The magnitude of placebo effects from physical and psychological 'sham' is unknown but could impact efficacy trials and treatment understanding. To quantify placebo effects, this systematic review of three-armed randomised controlled trials (RCTs) of physical and psychological interventions for pain compared outcomes in 'sham' control intervention and non-exposure arms.

METHODS

RCTs with treatment, 'sham' control intervention, and non-exposure groups were included, enrolling adults with any pain. A protocol was pre-registered (PROSPERO: CRD42023413324), and twelve databases searched from 2008 to July 2023. Trial methods and blinding were analysed descriptively and risk of bias assessed. Meta-analysis of pain measures at short-, medium- and long-term was performed with random-effects models of standardised mean differences (SMD).Studies were sub-grouped according to control intervention type.

RESULTS

Seventeen RCTs were included. The average short-term placebo effect was small (0.21 SMD, 0.1-0.33 95% CI, p = 0.0002, 1440 participants). It showed no heterogeneity (Tau2  = 0.1, I2  = 11%, p = 0.3), preventing meta-regression analyses of effect modifiers. However, sub-group analyses revealed larger placebo effects in manual control interventions compared to disabled devices and miscellaneous control interventions. Overall, placebo analgesia accounted for 39% of treatments' short-term effectiveness. No placebo effects were found at medium-term (7 RCTs, 381 participants) or long-term follow-up (3 RCTs, 173 participants).

CONCLUSIONS

The observed placebo analgesia has mechanistic and methodological implications, though its clinical importance may be limited. Control intervention design affects placebo effects, highlighting the importance of considering methodology in RCT interpretation. Review limitations include a small number of long-term studies and sample heterogeneity.

SIGNIFICANCE

This systematic review directly quantifies placebo effects from physical and psychological 'sham' control interventions and compares them to treatments' overall effectiveness. By doing so, the review enhances our understanding of placebo effects, their relative contribution in clinical trials, and their susceptibly to trial design. It poses further questions regarding the influence of blinding, participant expectations, and features of the therapeutic context. Overall, the insights provided by this review carry methodological significance and are important for the interpretation and synthesis of efficacy trials in this field.

Meta-epidemiologic review: blinding and sham treatment in clinical trial design for osteopathic manipulative treatment research

Objective

To analyze the consistency of study designs in osteopathic manipulative treatment (OMT) research, focusing on blinding protocols and the use of sham treatments.

Data Source and Study Selection

PubMed and CINAHL were searched in January 2022. A total of 83 research studies between 2009 and 2021 were selected based on the presence of a double- or single-blind study design and/or sham treatment.

Data Extraction and Analysis

Data regarding the primary outcome measures, blinding design, measures used to determine success of blinding, osteopathic technique used, and sham technique used for each eligible study were extracted and compared among different study designs.

Results

A total of 5968 subjects participated in the 83 trials. The study population mainly consisted of asymptomatic individuals (25%) and chronic back pain patients (19%). Light touch was employed most commonly (49%) as the sham treatment, followed by unrelated sham (20%) and incomplete maneuvers (20%). Most studies blinded the subjects (80%) or the outcome evaluator/data analyzer (71%), while only 20% studies blinded the osteopathic physicians.

Conclusions

Strict double-blinding is achievable for OMT clinical research by blinding the subjects and data collectors/analyzers rather than the osteopaths providing the actual treatment. The use of questionnaires to determine the success of blinding should be considered. Additionally, including OMT-naïve subjects is preferred to enhance blinding success. When designing a sham treatment, careful consideration should be given to blinding the data collector, accounting for the placebo effect, and incorporating an additional no-treatment control group to improve the rigor of the study design.

Identical movement control exercises with and without synchronized breathing for chronic non-specific low back pain:A randomized pilot trial

BACKGROUND

Exercise is a first-line treatment for chronic non-specific low back pain (CNSLBP). Exercise combined with specific breathing techniques have the potential to improve multifactorial outcomes. No previous studies, however, have compared outcomes between identical exercises with or without a specific breathing protocol in a uniform clinical study setting.

OBJECTIVES

1) To investigate the feasibility of combining synchronized breathing with movement control exercises and evaluate eligibility criteria, randomization procedures, and dropout rates. 2) To study the preliminary efficacy of the interventions on multifactorial outcome measures.

METHODS

Thirty subjects with CNSLBP were randomized into two groups. Both groups had four contact clinic visits where they received personalized home movement control exercises to practice over two months. The experimental group included a movement control exercise intervention combined with synchronized breathing techniques. Trial registration number: NCT05268822.

RESULTS

Feasibility was demonstrated by meeting the recruitment goal of 30 subjects within the pre-specified timeframe with enrolment rate of 24.8% (30/121). Synchronized breathing techniques were successfully adhered by participants. Home exercise adherence was nearly identical between the groups without any adverse events. Preliminary efficacy findings on pain intensity, disability, and self-efficacy in the experimental group exceeded the minimal clinically important difference. No such findings were observed in any outcome measures within the control group. Overall, multifactorial differences were consistent because nine out of eleven outcome measures showed greater improvements for the experimental group.

CONCLUSION

The synchronized breathing with movement control exercises protocol was feasible and may be more beneficial for improving multifactorial outcomes compared to identical exercises alone. Results suggested progression to a full-scale trial.

Chiropractic spinal manipulative therapy for acute neck pain: A 4-arm clinical placebo randomized controlled trial. A prospective study protocol

INTRODUCTION

Neck pain poses enormous individual and societal costs worldwide. Spinal manipulative therapy and Non-Steroidal Anti-Inflammatory Drug treatment are frequently used despite a lack of compelling efficacy data. This protocol describes a multicentre 4-arm, clinical placebo randomized controlled trial (RCT), investigating the efficacy of chiropractic spinal manipulative therapy (CSMT) versus sham CSMT, ibuprofen, and placebo medicine for acute neck pain. This superiority study will employ parallel groups, featuring a 1:1:1:1 allocation ratio.

MATERIAL AND METHODS

We will randomize 320 participants equally into four groups: CSMT, sham CSMT, ibuprofen, or placebo medicine. CSMT groups are single-blinded, while the medicine groups are double-blinded. Data will be collected at baseline (Day 0), during treatment and post-treatment. The primary endpoint will assess the difference in mean pain intensity from Day 0 to Day 14 on a numeric rating scale 0-10; the CSMT group is compared to sham CSMT, ibuprofen, and placebo medicine groups, respectively. Secondary endpoints will assess mean pain intensity and mean duration at different time points, and adverse events, blinding success, and treatment satisfaction, including comparison between ibuprofen and placebo medicine. Power calculation is based on a mean neck pain rating of 5 at Day 0, with standard deviation of 1 in all groups. Mean pain reduction at Day 14 is expected to be 60% in the CSMT group, 40% in sham CSMT and ibuprofen groups, and 20% in the placebo medicine group. A linear mixed model will compare the mean values for groups with corresponding 95% confidence intervals. P values below 0.017 will be considered statistically significant. All analyses will be conducted blinded from group allocation.

DISCUSSION

This RCT aims towards the highest research standards possible for manual-therapy RCTs owing to its two placebo arms. If CSMT and/or ibuprofen proves to be effective, it will provide evidence-based support for CSMT and/or ibuprofen for acute neck pain.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT05374057. EU Clinical Trials Register: EudraCT number: 2021-005483-21.

Factors That Predict Magnitude, Timing, and Persistence of Placebo-Like Response in Patients With Irritable Bowel Syndrome

BACKGROUND AND AIMS

Placebo response impedes the development of novel irritable bowel syndrome (IBS) therapies and the interpretability of randomized clinical trials. This study sought to characterize the magnitude, timing, and durability of IBS symptom relief in patients undergoing a non-drug placebo-like control.

METHODS

One hundred forty-five Rome III-diagnosed patients (80% F, M age = 42 years) were assigned to education/nondirective support delivered over a 10-week acute phase. Treatment response was based on the IBS version of the Clinical Global Improvement Scale completed 2 weeks after treatment ended. Candidate predictors were assessed at baseline (eg, emotion regulation, pain catastrophizing, distress, neuroticism, stress, somatization, gastrointestinal-specific anxiety) or clinically relevant points during treatment (patient-provider relationship, treatment expectancy/credibility).

RESULTS

Midtreatment response was associated with lower levels of stress and somatization at baseline and greater patient-provider agreement on treatment tasks (P < .001). Treatment response was associated with baseline gastroenterologist-rated IBS severity, anxiety, ability to reappraise emotions to reduce their impact [cognitive reappraisal], and agreement that provider and patient shared goals from provider perspective (P < .001). The day-to-day ability to reappraise emotions at baseline distinguished rapid from delayed placebo responders (P = .011).

CONCLUSION

Patient beliefs (eg, perceived stress, cognitive reappraisal) impacted the magnitude, timing, and persistence of placebo response measured at midway point of acute phase and 2 weeks after treatment discontinuation. Baseline beliefs that patients could alter the impact of stressful events by rethinking their unpleasantness distinguished rapid vs delayed placebo responders. Collaborative agreement between doctor and patient around shared tasks/goals from the clinician perspective predicted placebo response.

Immediate systemic neuroimmune responses following spinal mobilisation and manipulation in people with non-specific neck pain: a randomised placebo-controlled trial

Spinal mobilisation/manipulation is a common intervention for spinal pain, yet the working mechanisms are largely unknown. A randomised placebo-controlled trial was conducted to (1) compare the immediate neuroimmune responses following spinal mobilisation/manipulation and placebo spinal mobilisation/manipulation; (2) compare the immediate neuroimmune responses of those with a good outcome with those of a poor outcome following spinal mobilisation/manipulation; and (3) explore the association between neuroimmune responses and pain reduction. One hundred patients were randomly allocated to spinal mobilisation/manipulation or a placebo mobilisation/manipulation. Primary outcomes were whole blood in-vitro evoked released concentrations of IL-1β and TNF-α measured 10 min and 2 h after the intervention. Immediate effects were studied because successful mobilisation/manipulation is often associated with immediate pain reduction, and immediate neuroimmune responses are less affected by potential confounders than long-term responses. Secondary outcomes included multiple systemic inflammatory marker concentrations, phenotypic analysis of white blood cells and clinical outcomes. Outcomes were compared between the experimental and placebo group, and between people with a good and poor outcome in the experimental group. Estimates of intervention effects were based on intention-to-treat analyses, by using linear mixed-effect models. Although there was a substantial difference in pain reduction between groups (mean (SD) difference visual analogue scale: 30 (21) mm at 10 min and 32 (21) mm at 2 h (p < 0.001) in favour of mobilisation/manipulation, there were no differences in primary outcomes between groups or between people with a good and poor outcome (p ≥ 0.10). In conclusion, possible neuroimmune responses following spinal mobilisations/manipulation cannot be identified at a systemic level. Future research may focus on longer treatment duration and more localised neuroimmune responses.

Research objectives and general considerations for pragmatic clinical trials of pain treatments: IMMPACT statement

ABSTRACT

Many questions regarding the clinical management of people experiencing pain and related health policy decision-making may best be answered by pragmatic controlled trials. To generate clinically relevant and widely applicable findings, such trials aim to reproduce elements of routine clinical care or are embedded within clinical workflows. In contrast with traditional efficacy trials, pragmatic trials are intended to address a broader set of external validity questions critical for stakeholders (clinicians, healthcare leaders, policymakers, insurers, and patients) in considering the adoption and use of evidence-based treatments in daily clinical care. This article summarizes methodological considerations for pragmatic trials, mainly concerning methods of fundamental importance to the internal validity of trials. The relationship between these methods and common pragmatic trials methods and goals is considered, recognizing that the resulting trial designs are highly dependent on the specific research question under investigation. The basis of this statement was an Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials (IMMPACT) systematic review of methods and a consensus meeting. The meeting was organized by the Analgesic, Anesthetic, and Addiction Clinical Trial Translations, Innovations, Opportunities, and Networks (ACTTION) public-private partnership. The consensus process was informed by expert presentations, panel and consensus discussions, and a preparatory systematic review. In the context of pragmatic trials of pain treatments, we present fundamental considerations for the planning phase of pragmatic trials, including the specification of trial objectives, the selection of adequate designs, and methods to enhance internal validity while maintaining the ability to answer pragmatic research questions.

Mechanisms of chiropractic spinal manipulative therapy for patients with chronic primary low back pain: protocol for a mechanistic randomised placebo-controlled trial

INTRODUCTION

Chronic low back pain (CLBP) is a highly prevalent and disabling condition. Identifying subgroups of patients afflicted with CLBP is a current research priority, for which a classification system based on pain mechanisms was proposed. Spinal manipulative therapy (SMT) is recommended for the management of CLBP. Yet, little data are available regarding its mechanisms of action, making it difficult to match this intervention to the patients who may benefit the most. It was suggested that SMT may influence mechanisms associated with central sensitisation. Therefore, classifying patients with CLBP according to central sensitisation mechanisms may help predict their response to SMT.

METHODS AND ANALYSIS

This protocol describes a randomised placebo-controlled trial aiming to examine which variables linked to central sensitisation may help predict the clinical response to SMT in a cohort of patients with CLBP. One hundred patients with chronic primary low back pain will be randomised to receive 12 sessions of SMT or placebo SMT over a 4-week period. Pain intensity and disability will be assessed as primary outcomes after completing the 4-week treatment (primary endpoint), and at 4-week and 12-week follow-ups. Baseline values of two pain questionnaires, lumbar pressure pain thresholds, concentrations of an inflammatory cytokine and expectations of pain relief will be entered as predictors of the response to SMT in a multiple regression model. Changes in these variables after treatment will be used in a second multiple regression model. The reference values of these predictors will be measured from 50 age and sex-matched healthy controls to allow interpretation of values in patients. Mixed analyses of variance will also be conducted to compare the primary outcomes and the predictors between groups (SMT vs placebo) over time (baseline vs post-treatment).

ETHICS AND DISSEMINATION

Ethical approval was granted by the Fundación Jiménez Díaz Clinical Research Ethics Committee.

TRIAL REGISTRATION NUMBER

NCT05162924.

The effectiveness of manual and exercise therapy on headache intensity and frequency among patients with cervicogenic headache: a systematic review and meta-analysis

BACKGROUND

Cervicogenic headache is a secondary headache, and manual therapy is one of the most common treatment choices for this and other types of headache. Nonetheless, recent guidelines on the management of cervicogenic headache underlined the lack of trials comparing manual and exercise therapy to sham or no-treatment controls. The main objective of this systematic review and meta-analysis was to assess the effectiveness of different forms of manual and exercise therapy in people living with cervicogenic headache, when compared to other treatments, sham, or no treatment controls.

METHODS

Following the PRISMA guidelines, the literature search was conducted until January 2022 on MEDLINE, CENTRAL, DOAJ, and PEDro. Randomized controlled trials assessing the effects of manual or exercise therapy on patients with cervicogenic headache with headache intensity or frequency as primary outcome measures were included. Study selection, data extraction and Risk of Bias (RoB) assessment were done in duplicate. GRADE was used to assess the quality of the evidence.

RESULTS

Twenty studies were included in the review, with a total of 1439 patients. Common interventions were spinal manipulation, trigger point therapy, spinal mobilization, scapulo-thoracic and cranio-cervical exercises. Meta-analysis was only possible for six manual therapy trials with sham comparators. Data pooling showed moderate-to-large effects in favour of manual therapy for headache frequency and intensity at short-term, small-to-moderate for disability at short-term, small-to-moderate for headache intensity and small for headache frequency at long-term. A sensitivity meta-analysis of low-RoB trials showed small effects in favor of manual therapy in reducing headache intensity, frequency and disability at short and long-term. Both trials included in the sensitivity meta-analysis studied spinal manipulation as the intervention of interest. GRADE assessment showed moderate quality of evidence.

CONCLUSION

The evidence suggests that manual and exercise therapy may reduce headache intensity, frequency and disability at short and long-term in people living with cervicogenic headache, but the overall RoB in most included trials was high. However, a sensitivity meta-analysis on low-RoB trials showed moderate-quality evidence supporting the use of spinal manipulation compared to sham interventions. More high-quality trials are necessary to make stronger recommendations, ideally based on methodological recommendations that enhance comparability between studies. Trial registration The protocol for this meta-analysis was pre-registered on PROSPERO under the registration number CRD42021249277.