No long-term effects after a 3-week open-label placebo treatment for chronic low back pain: a 3-year follow-up of a randomized controlled trial

An update on non-pharmacological interventions for pain relief

Chronic pain affects a substantial portion of the population, yet current treatments often fail to provide adequate relief. Non-pharmacological interventions, which target behaviors and brain processes underlying the experience of pain, hold promises in offering relief for people with chronic pain. This review consolidates the current knowledge concerning the efficacy of non-pharmacological interventions for chronic pain. We focus on psychological interventions (e.g., cognitive behavioral therapy-based interventions and emotion-based therapies) that use mental techniques and physical practices (e.g., exercise, massage, acupuncture, and yoga) that use body techniques to reduce pain. The efficacy of neuromodulation is also discussed. Given that placebo and expectation effects may enhance benefits for non-pharmacological interventions, we also discuss placebo interventions and expectation management practices. Finally, we describe digital therapeutics as an emerging approach for managing chronic pain. We argue that non-pharmacological interventions are critical adjunctive or stand-alone interventions for chronic pain conditions.

Effects of an open-label placebo on visual attention directed to food high in sugar, appetite, and desire for sweet taste

BACKGROUND

Interventions with deceptive placebos can reduce visual attention directed to high-calorie sweets. Open-label placebos (OLPs), which avoid the ethical concerns associated with deception, have shown promise in various fields. This is the first study to test the effects of OLPs on appetite, desire for sweet taste and visual attention for high-sugar foods.

METHODS

In this preregistered laboratory study, fifty-three females (mean age = 22.8 years) were presented with image pairs depicting food high vs. low in sugar as well as non-food items. The image presentation was conducted once with and without an OLP. Different indicators of visual attention (total fixation duration, number of fixations, first fixation location), general appetite and the desire to eat the depicted food items were assessed. Moreover, participants tasted and evaluated a sucrose solution to determine their desire for the sweet taste.

RESULTS

The OLP decreased general appetite (p = .005, ηp2 = .09) and the desire to taste the sucrose solution again (p = .036, d = .30). The intervention did not affect visual attention: both conditions (with/without OLP) were characterized by a longer total fixation duration and a higher number of fixations for images with low-sugar food compared to high-sugar food when presented alongside images of non-food.

CONCLUSION

The OLP did not reduce visual attention toward images of high-sugar food, and OLP effects were only observed in self-report measures. Future research should elaborate on how the efficacy of OLPs can be improved or whether deception is necessary to decrease visual attention via placebos.

Open-Label Placebo Injection for Chronic Back Pain With Functional Neuroimaging: A Randomized Clinical Trial

Importance

Chronic back pain (CBP) is a leading cause of disability. Placebo treatments often provide as much pain relief as bona fide treatments, such as steroid injections. Open-label (honestly prescribed) placebos (OLPs) may relieve CBP without deception, but OLP mechanisms remain poorly understood.

Objective

To investigate the long-term efficacy and neurobiological mechanisms of OLP for CBP.

Design, Setting, and Participants

A randomized clinical trial of CBP with longitudinal functional magnetic resonance imaging (MRI) comparing OLP with usual care, with 1-year follow-up, was conducted in a university research setting and a community orthopedic clinic. Participants were individuals aged 21 to 70 years with CBP. The trial was conducted from November 2017 to August 2018, with 1-year follow-up completed by November 2019. Data analysis was performed from April 2020 to May 2024. The primary analysis was conducted on an intention-to-treat sample.

Interventions

Participants randomized to OLP received a 1-time subcutaneous lumbar saline injection presented as placebo accompanied by information about the power of placebo to relieve pain, alongside their ongoing care. Usual care participants continued their ongoing care.

Main Outcomes and Measures

The primary outcome was pain intensity (0-10, with 0 indicating no pain and 10 the most intense) at 1 month posttreatment. Secondary outcomes included pain interference, depression, anxiety, anger, and sleep quality. Functional MRI was performed before and after treatment during evoked and spontaneous back pain.

Results

A total of 101 adults (52 [51.4%] females; mean [SD] age, 40.4 [15.4] years) with moderate severity CBP (mean [SD], 4.10 [1.25] intensity; duration, 9.7 [8.5] years) were enrolled. Compared with usual care, OLP reduced CBP intensity posttreatment (relative reduction, 0.61; Hedges g = 0.45; 95% CI, -0.89 to 0.04; P = .02). Through 1-year follow-up, pain relief did not persist, although significant benefits were observed for depression, anger, anxiety, and sleep disruption (Hedges g = 0.3-0.5; all P < .03). Brain responses to evoked back pain for OLP vs usual care increased in rostral anterior cingulate and ventromedial prefrontal cortex and decreased in somatomotor cortices and thalamus. During spontaneous pain, functional connectivity analyses identified OLP vs usual care increases in ventromedial prefrontal cortex connectivity to the rostral ventral medulla, a pain-modulatory brainstem nucleus. No adverse effects of treatment were reported by participants.

Conclusions and Relevance

In this randomized clinical trial of OLP vs usual care, a single nondeceptive placebo injection reduced CBP intensity for 1 month posttreatment and provided benefits lasting for at least 1 year posttreatment. Brain mechanisms of OLP in a clinical population overlap with those of deceptive placebos in healthy volunteers, including engagement of prefrontal-brainstem pain modulatory pathways.

Trial Registration

ClinicalTrials.gov Identifier: NCT03294148.

Treatment Expectations-You Get What You Expect-and Depression Plays a Role

Positive treatment expectations demonstrably shape treatment outcomes regarding pain and disability in patients with chronic low back pain. However, knowledge about positive and negative treatment expectations as putative predictors of interindividual variability in treatment outcomes is sparse, and the role of other psychological variables of interest, especially of depression as a known predictor of long-term disability, is lacking. We present results of the first prospective study considering expectations in concert with depression in a sample of 200 patients with chronic low back pain undergoing an inpatient interdisciplinary multimodal pain therapy. We analyzed the characteristics of pain and disability, treatment expectation, and depression assessed at the beginning (T0), at the end of (T1), and at 3-month follow-up (T2) of interdisciplinary multimodal pain therapy. Treatment expectations did emerge as a significant predictor of changes in pain intensity and disability, respectively, showing that positive expectations were associated with better treatment outcomes. Mediation analyses revealed a partially mediating effect of treatment expectations on the relation between depression and pain outcomes. PERSPECTIVE: These results expand knowledge regarding the role of treatment expectations in individual treatment outcome trajectories in chronic pain patients, paving the way for much-needed efforts toward optimizing patient expectations and personalized approaches in clinical settings.

Boosting treatment outcomes via the patient-practitioner relationship, treatment-beliefs or therapeutic setting. A systematic review with meta-analysis of contextual effects in chronic musculoskeletal pain

OBJECTIVE: To ascertain whether manipulating contextual effects (e.g. interaction with patients, or beliefs about treatments) boosted the outcomes of non-pharmacological and non-surgicaltreatments for chronic primary musculoskeletal pain. DESIGN: Systematic review of randomized controlled trials. DATA SOURCES: We searched for trials in six databases, citation tracking, and clinical trials registers. We included trials that compared treatments with enhanced contextual effects with the same treatments without enhancement in adults with chronic primary musculoskeletal pain. DATA SYNTHESIS: The outcomes of interest were pain intensity, physical functioning, global ratings of improvement, quality of life, depression, anxiety, and sleep. We evaluated risk of bias and certainty of the evidence using Cochrane Risk of Bias tool 2.0 and the GRADE approach, respectively. RESULTS: Of 17637 records, we included 10 trials with 990 participants and identified 5 ongoing trials. The treatments were acupuncture, education, exercise training, and physical therapy. The contextual effects that were improved in the enhanced treatments were patient-practitioner relationship, patient beliefs and characteristics, therapeutic setting/environment, and treatment characteristics. Our analysis showed that improving contextual effects in non-pharmacological and non-surgical treatments may not make much difference on pain intensity (mean difference [MD] : -1.77, 95%-CI: [-8.71; 5.16], k = 7 trials, N = 719 participants, Scale: 0-100, GRADE: Low)) or physical functioning (MD: -0.27, 95%-CI: [-1.02; 0.49], 95%-PI: [-2.04; 1.51], k = 6 , N = 567, Scale: 0-10, GRADE: Low) in the short-term and at later follow-ups. Sensitivity analyses revealed similar findings. CONCLUSION: Whilst evidence gaps exist, per current evidence it may not be possible to achieve meaningful benefit for patients with chronic musculoskeletal pain by manipulating the context of non-pharmacological and non-surgical treatments. TRIAL REGISTRATION: This systematic review was prospectively registered in PROSPERO (registration number: CRD42023391601).

Placebo-resistant gut bacteria: Akkermansia muciniphila spp. and Familial Mediterranean fever disease

INTRODUCTION

Despite numerous investigations into the impact of drugs/probiotics on the gut microbiota composition in Familial Mediterranean Fever (FMF) patients, the question as to whether there exists a significant bacterial diversity(ies) independent of the placebo effect that can be reliably considered in clinical and nutritional trials remains unresolved.

METHODS

This study represents the in augural analysis of the placebo's influence on the gut microbiota of both healthy individuals and FMF afflicted men, utilizing previously collected data from PhyloChip™ DNA microarray experiments. A total of 15 healthy and 15 FMF male volunteers, aged 18 to 50, participated in this partially randomized placebo trial, which is accessible through the GEO Series accession number GSE111835.

RESULTS AND DISCUSSION

Key findings from current investigations include i. the anticipated divergence in gut bacteria resistance to placebo between healthy and FMF individuals, ii. the minor impact of placebo on gut bacterial diversities in healthy individuals, with Enterobacteriaceae diversities identified as placebo-resistant among "healthy" gut bacteria, and iii. the comprehensive influence of placebo on all bacterial phyla in the gut microbiome of FMF patients, extending to nearly all bacterial genera, except for the resilience of gut Akkermansia muciniphila spp. to placebo in FMF patients. This study underscores the susceptibility of Faecalibacterium, Blautia, and Clostridium genera to placebo. Consequently, this investigation holds significance for the proper design of placebo-controlled trials and establishes a foundation for further exploration of the gut-brain axis. Furthermore, it contributes valuable insights to discussions regarding proposals for probiotic therapies, particularly focusing on Faecalibacterium spp., Blautia spp., and Clostridium spp.

The STAR care pathway for patients with chronic pain after total knee replacement: four-year follow-up of a randomised controlled trial

BACKGROUND

The Support and Treatment After Replacement (STAR) care pathway is a clinically important and cost-effective intervention found to improve pain outcomes over one year for people with chronic pain three months after total knee replacement (TKR). We followed up STAR trial participants to evaluate the longer-term clinical- and cost-effectiveness of this care pathway.

METHODS

Participants who remained enrolled on the trial at one year were contacted by post at a median of four years after randomisation and invited to complete a questionnaire comprising the same outcomes collected during the trial. We captured pain (co-primary outcome using the Brief Pain Inventory (BPI) pain severity and interference scales; scored 0-10, best to worst), function, neuropathic characteristics, emotional aspects of pain, health-related quality of life, and satisfaction. Electronic hospital informatics data on hospital resource use for the period of one to four years post-randomisation were collected from participating hospital sites. The economic evaluation took an National Health Service (NHS) secondary care perspective, with a four-year time horizon.

RESULTS

Overall, 226/337 (67%) of participants returned completed follow-up questionnaires, yielding adjusted between-group differences in BPI means of -0.42 (95% confidence interval, CI (-1.07, 0.23); p = 0.20) for pain severity and - 0.64 (95% CI -1.41, 0.12); p = 0.10) for pain interference. Analysis using a multiple imputed data set (n = 337) showed an incremental net monetary benefit in favour of the STAR care pathway of £3,525 (95% CI -£990 to £8,039) at a £20,000/QALY willingness-to-pay threshold, leading to a probability that the intervention was cost-effective of 0.94.

CONCLUSIONS

The magnitude of the longer-term benefits of the STAR care pathway are uncertain due to attrition of trial participants; however, there is a suggestion of some degree of sustained clinical benefit at four years. The care pathway remained cost-effective at four years.

TRIAL REGISTRATION

ISRCTN: 92,545,361.

Open-label placebo treatment does not enhance cognitive abilities in healthy volunteers

The use of so-called 'smart drugs' such as modafinil to improve cognitive performance has recently attracted considerable attention. However, their side effects have limited user enthusiasm. Open-label placebo (OLP) treatment, i.e., inert treatments that are openly disclosed to individuals as having no active pharmacological ingredient, has been shown to improve various medical symptoms and conditions, including those related to cognitive performance. OLP treatment could therefore be an exciting alternative to pharmacological cognitive enhancers. Here, we used a randomized-controlled design to investigate the effect of a 21-day OLP treatment on several sub-domains of cognitive performance in N = 78 healthy volunteers. Subjective and objective measures of cognitive performance as well as different measures of well-being were obtained before and after the treatment period. Using a combination of classic Frequentist and Bayesian analysis approaches showed no additional benefit from OLP treatment in any of the subjective or objective measures of cognitive performance. Our study thus highlights possible limitations of OLP treatment in boosting cognitive performance in healthy volunteers. These findings are discussed in the light of expectancy-value considerations that may determine OLP efficacy.

Study protocol: randomised controlled trial of conditioned open-label placebo (COLP) for perioperative pain management in patients with head and neck cancer

INTRODUCTION

Patients with head and neck cancer have a substantial risk of chronic opioid dependence following surgery due to pain and psychosocial consequences from both the disease process and its treatments. Conditioned open-label placebos (COLPs) have been effective for reducing the dose of active medication required for a clinical response across a wide range of medical conditions. We hypothesise that the addition of COLPs to standard multimodal analgesia will be associated with reduced baseline opioid consumption by 5 days after surgery in comparison to standard multimodal analgesia alone in patients with head and neck cancer.

METHODS AND ANALYSIS

This randomised controlled trial will evaluate the use of COLP for adjunctive pain management in patients with head and neck cancer. Participants will be randomised with 1:1 allocation to either the treatment as usual or COLP group. All participants will receive standard multimodal analgesia, including opioids. The COLP group will additionally receive conditioning (ie, exposure to a clove oil scent) paired with active and placebo opioids for 5 days. Participants will complete surveys on pain, opioid consumption and depression symptoms through 6 months after surgery. Average change in baseline opioid consumption by postoperative day 5 and average pain levels and opioid consumption through 6 months will be compared between groups.

ETHICS AND DISSEMINATION

There remains a demand for more effective and safer strategies for postoperative pain management in patients with head and neck cancer as chronic opioid dependence has been associated with decreased survival in this patient population. Results from this study may lay the groundwork for further investigation of COLPs as a strategy for adjunctive pain management in patients with head and neck cancer. This clinical trial has been approved by the Johns Hopkins University Institutional Review Board (IRB00276225) and is registered on the National Institutes of Health Clinical Trials Database.

TRIAL REGISTRATION NUMBER

NCT04973748.