Research approaches for evaluating opioid sparing in clinical trials of acute and chronic pain treatments: Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials recommendations

An Adaptive Pragmatic Randomized Controlled Trial of Emergency Department Acupuncture for Acute Musculoskeletal Pain Management

STUDY OBJECTIVE

Acute musculoskeletal pain in emergency department (ED) patients is frequently severe and challenging to treat with medications alone. The purpose of this study was to determine the feasibility, acceptability, and effectiveness of adding ED acupuncture to treat acute episodes of musculoskeletal pain in the neck, back, and extremities.

METHODS

In this pragmatic 2-stage adaptive open-label randomized clinical trial, Stage 1 identified whether auricular acupuncture (AA; based on the battlefield acupuncture protocol) or peripheral acupuncture (PA; needles in head, neck, and extremities only), when added to usual care was more feasible, acceptable, and efficacious in the ED. Stage 2 assessed effectiveness of the selected acupuncture intervention(s) on pain reduction compared to usual care only (UC). Licensed acupuncturists delivered AA and PA. They saw and evaluated but did not deliver acupuncture to the UC group as an attention control. All participants received UC from blinded ED providers. Primary outcome was 1-hour change in 11-point pain numeric rating scale.

RESULTS

Stage 1 interim analysis found both acupuncture styles similar, so Stage 2 continued all 3 treatment arms. Among 236 participants randomized, demographics and baseline pain were comparable across groups. When compared to UC alone, reduction in pain was 1.6 (95% confidence interval [CI]: 0.7 to 2.6) points greater for AA+UC and 1.2 (95% CI: 0.3 to 2.1) points greater for PA+UC patients. Participants in both treatment arms reported high satisfaction with acupuncture.

CONCLUSION

ED acupuncture is feasible and acceptable and can reduce acute musculoskeletal pain better than UC alone.

Intraoperative pharmacologic opioid minimisation strategies and patient-centred outcomes after surgery: a scoping review

BACKGROUND

Postoperative patient-centred outcome measures are essential to capture the patient's experience after surgery. Although a large number of pharmacologic opioid minimisation strategies (i.e. opioid alternatives) are used for patients undergoing surgery, it remains unclear which strategies are most promising in terms of patient-centred outcome improvements. This scoping review had two main objectives: (1) to map and describe evidence from clinical trials assessing the patient-centred effectiveness of pharmacologic intraoperative opioid minimisation strategies in adult surgical patients, and (2) to identify promising pharmacologic opioid minimisation strategies.

METHODS

We searched MEDLINE, Embase, CENTRAL, Web of Science, and CINAHL databases from inception to February 2023. We included trials investigating the use of opioid minimisation strategies in adult surgical patients and reporting at least one patient-centred outcome. Study screening and data extraction were conducted independently by at least two reviewers.

RESULTS

Of 24,842 citations screened for eligibility, 2803 trials assessed the effectiveness of intraoperative opioid minimisation strategies. Of these, 457 trials (67,060 participants) met eligibility criteria, reporting at least one patient-centred outcome. In the 107 trials that included a patient-centred primary outcome, patient wellbeing was the most frequently used domain (55 trials). Based on aggregate findings, dexmedetomidine, systemic lidocaine, and COX-2 inhibitors were promising strategies, while paracetamol, ketamine, and gabapentinoids were less promising. Almost half of the trials (253 trials) did not report a protocol or registration number.

CONCLUSIONS

Researchers should prioritise and include patient-centred outcomes in the assessment of opioid minimisation strategy effectiveness. We identified three potentially promising pharmacologic intraoperative opioid minimisation strategies that should be further assessed through systematic reviews and multicentre trials. Findings from our scoping review may be influenced by selective outcome reporting bias.

STUDY REGISTRATION

OSF - https://osf.io/7kea3.

Model-Based Meta-Analysis Supporting the Combination of Acetaminophen and Topical Diclofenac in Acute Pain: A Therapy for Mild-to-Moderate Osteoarthritis Pain?

INTRODUCTION

Acetaminophen and topical diclofenac (AtopD) have complementary mechanisms of action and are therefore candidates for combination use in osteoarthritis (OA) pain. However, an evidence gap exists on their combination use in OA pain. This study aimed to assess the effects of this combination and compare its performance relative to monotherapies on pain score reduction and opioid-sparing effect by leveraging evidence from acute pain setting using a model-based meta-analysis (MBMA).

METHODS

A literature search was conducted using the MEDLINE database to identify randomized controlled trials (RCTs) studying the combination for acute pain. Subsequently, an MBMA of RCTs was implemented in conjunction with extrapolation principles to infer efficacy in the population of interest. Pain score reduction and opioid-sparing effect (OSE) were selected as the measures of efficacy.

RESULTS

A total of 11 RCTs encompassing 1396 patients were included. Exploratory evaluation revealed AtopD combination to show greater pain score reduction versus acetaminophen monotherapy. However, pain score reduction was more susceptible to confounding by opioid patient-controlled analgesia (PCA) than OSE. Therefore, a parsimonious MBMA evaluating OSE was developed from 5 of the 11 RCTs (n = 353 patients). The analysis revealed a statistically significant interaction coefficient, suggesting a reduction of 32% in opioid use with the combination versus acetaminophen monotherapy. Differences in the effect size of the combination were less conclusive versus diclofenac monotherapy.

CONCLUSION

Our results indicate greater pain reduction and opioid-sparing efficacy for the AtopD combination versus acetaminophen monotherapy. Given the similar pain pathways and mechanisms of action of the two drugs in acute and mild-to-moderate OA pain, comparable beneficial effects from the combination therapy may be anticipated following extrapolation to chronic OA pain. Prospective RCTs and real-world studies in OA pain are needed to confirm the differences in the efficacy of the combination treatment observed in our study.

Transcutaneous electrical acupoint stimulation for cancer-related pain management in patients receiving chronic opioid therapy: a randomized clinical trial

PURPOSE

The opioid crisis resulting from its use disorder and overdose poses additional challenges for cancer pain management. The American Society of Clinical Oncology Practice Guideline recommends acupuncture therapy for the management of adult cancer-related pain (CRP), but the effectiveness of transcutaneous electrical acupoint stimulation (TEAS) on CRP remains uncertain.

METHODS

This 5-week prospective randomized clinical trial was conducted at 2 hospitals in China, and participants with CRP receiving chronic opioid therapy were randomized 1:1 into two groups between December 2014 and June 2018. The true TEAS group underwent 15 sessions of TEAS treatments over 3 consecutive weeks, while the control group received sham stimulation. The primary outcome was the numerical rating scale (NRS) score in the past 24h at week 3. The secondary outcomes included morphine equivalent daily dose, quality of life and adverse events.

RESULTS

A total of 159 participants were included in the modified intention-to-treat population. The baseline characteristics were similar in both groups. The mean NRS scores were 0.98 points at week 3 in the true TEAS group and 1.41 points in the sham group, with the mean difference between groups of -0.43 points (P < 0.001; OR = 0.68, P < 0.05). The proportion of patients with NRS reduction more than thirty percentage at week 3 was 50.00% in the true TEAS group and 35.44% in the sham group (RD = 0.15, P > 0.05; RR = 1.41, P > 0.05). No significant difference in pain intensity between the two groups was observed during the follow-up period without TEAS intervention (week 4, OR = 0.83, P > 0.05; week 5, OR = 0.83, P > 0.05). The Karnofsky Performance Status value suggested that patients in the true TEAS group experienced an improved quality of life (Between-group differences: week 3, 3.5%, P < 0.05; week 4, 4.6%, P < 0.001; week 5, 5.6%, P < 0.001).

CONCLUSIONS

The 3-week application of TEAS in patients with CRP receiving chronic opioid therapy resulted in a statistically significant reduction in pain scores, but the observed reduction was of uncertain clinical significance. The prolonged analgesic effect of TEAS was not confirmed in this trial.

CLINICALTRIAL

GOV: ChiCTR-TRC-13003803.

Text messaging intervention to support patients with chronic pain during prescription opioid tapering: protocol for a double-blind randomised controlled trial

INTRODUCTION

Increases in pain and interference with quality of life is a common concern among people with chronic non-cancer pain (CNCP) who are tapering opioid medications. Research indicates that access to social and psychological support for pain self-management may help people to reduce their opioid dose without increasing pain and interference. This study evaluates the efficacy of a text messaging intervention designed to provide people with CNCP with social and psychological support for pain self-management while tapering long-term opioid therapy (LTOT) under the guidance of their prescriber.

METHODS AND ANALYSIS

A double-blind randomised controlled trial will be conducted. Patients with CNCP (n=74) who are tapering LTOT will be enrolled from across Australia. Participants will continue with their usual care while tapering LTOT under the supervision of their prescribing physician. They will randomly receive either a psychoeducational video and supportive text messaging (two Short Message Service (SMS) per day) for 12 weeks or the video only. The primary outcome is the pain intensity and interference assessed by the Pain, Enjoyment of Life and General Activity scale. Secondary outcomes include mood, self-efficacy, pain cognitions, opioid dose reduction, withdrawal symptoms, and acceptability, feasibility, and safety of the intervention. Participants will complete questionnaires at baseline and then every 4 weeks for 12 weeks and will be interviewed at week 12. This trial will provide evidence for the efficacy of a text messaging intervention to support patients with CNCP who are tapering LTOT. If proven to be efficacious and safe, this low-cost intervention can be implemented at scale.

ETHICS AND DISSEMINATION

The study protocol was reviewed and approved by the Northern Sydney Local Health District (Australia). Study results will be published in peer-reviewed journals and presented at scientific and professional meetings.

TRIAL REGISTRATION NUMBER

ACTRN12622001423707.

Only 1% of Total Knee Arthroplasty Clinical Trials Report Patient Opioid Use Before or After Surgery: A Systematic Review

OBJECTIVES

Many clinical trials report significant improvements in osteoarthritis-related pain and function after total knee arthroplasty (TKA). Opioids are commonly prescribed for pain management of knee osteoarthritis and also perioperative pain after surgery. The extent of persistent opioid use after TKA is unknown. Because up to 20% of individuals have poor outcomes after TKA and prior opioid use is a risk factor for future opioid use, treatment effects from TKA clinical trials would be better understood by assessing opioid use data from trial participants. The purpose of this review was to determine the proportion of participants in TKA trials with opioid use before surgery and persistent use after surgery and how well clinical trials capture and report these variables.

MATERIALS AND METHODS

A systematic review of the literature (5 databases: CINAHL Cochrane CENTRAL, Embase, PubMed, and Web of Science) was conducted to assess the reporting of opioid use in TKA clinical trials. All opioid use was extracted, both prior and postoperatively. Long-term opioid use was determined using 4 different contemporary definitions to increase the sensitivity of the assessment.

RESULTS

The search produced 24,252 titles and abstracts, and 324 met the final inclusion criteria. Only 4 of the 324 trials (1.2%) reported any type of opioid use; 1 identified prior opioid use, and none reported long-term opioid use after surgery. Only 1% of TKA clinical trials in the past 15 years reported any opioid use.

DISCUSSION

Based on available research, it is not possible to determine if TKA is effective in reducing reliance on opioids for pain management. It also highlights the need to better track and report prior and long-term opioid use as a core outcome in future TKA trials.

Interdisciplinary strategies to prevent long-term and detrimental opioid use following trauma: a stakeholder consensus study

OBJECTIVE

Prolonged opioid use is common following traumatic injuries. Although preventive strategies have been recommended, the evidence supporting their use is low. The objectives of this study were to select interdisciplinary strategies to prevent long-term, detrimental opioid use in trauma patients for further evaluation and to identify implementation considerations.

DESIGN

A consensus study using the nominal group technique.

SETTING

Four trauma systems in Canada.

SUBJECTS

Participants included expert clinicians and decision makers, and people with lived experience.

METHODS

Participants had to discuss the relevance and implementation of 15 strategies and then rank them using a 7-point Likert scale. Implementation considerations were identified through a synthesis of discussions.

RESULTS

A total of 41 expert stakeholders formed the nominal groups. Overall, eight strategies were favored: 1) using multimodal approach for pain management, 2) professional follow-up in physical health, 3) assessment of risk factors for opioid misuse, 4) physical stimulation, 5) downward adjustment of opioids based on patient recovery, 6) educational intervention for patients, 7) training offered to professionals on how to prescribe opioids, and 8) optimizing communication between professionals working in different settings. Discussions with expert stakeholders revealed the rationale for the selected strategies and identified issues to consider when implementing them.

CONCLUSION

This stakeholder consensus study identified, for further scientific study, a set of interdisciplinary strategies to promote appropriate opioid use following traumatic injuries. These strategies could ultimately decrease the burden associated with long-term opioid use.

Opioid dose and pain effects of an online pain self-management program to augment usual care in adults with chronic pain: a multisite randomized clinical trial

ABSTRACT

Readily accessible nonpharmacological interventions that can assist in opioid dose reduction while managing pain is a priority for adults receiving long-term opioid therapy (LOT). Few large-scale evaluations of online pain self-management programs exist that capture effects on reducing morphine equivalent dose (MED) simultaneously with pain outcomes. An open-label, intent-to-treat, randomized clinical trial recruited adults (n = 402) with mixed chronic pain conditions from primary care and pain clinics of 2 U.S. academic healthcare systems. All participants received LOT-prescriber-provided treatment of MED ≥ 20 mg while receiving either E-health (a 4-month subscription to the online Goalistics Chronic Pain Management Program), or treatment as usual (TAU). Among 402 participants (279 women [69.4%]; mean [SD] age, 56.7 [11.0] years), 200 were randomized to E-health and 202 to TAU. Of 196 E-heath participants, 105 (53.6%) achieved a ≥15% reduction in daily MED compared with 85 (42.3%) of 201 TAU participants (odds ratio, 1.6 [95% CI, 1.1-2.3]; P = 0.02); number-needed-to-treat was 8.9 (95% CI, 4.8, 66.0). Of 166 E-health participants, 24 (14.5%) achieved a ≥2 point decrease in pain intensity vs 13 (6.8%) of 192 TAU participants (odds ratio, 2.4 [95% CI, 1.2-4.9]; P = 0.02). Benefits were also observed in pain knowledge, pain self-efficacy, and pain coping. The findings suggest that for adults on LOT for chronic pain, use of E-health, compared with TAU, significantly increased participants' likelihood of clinically meaningful decreases in MED and pain. This low-burden online intervention could assist adults on LOT in reducing daily opioid use while self-managing pain symptom burdens.

Implementation of a peri-operative pain-management algorithm reduces the use of opioid analgesia following pelvic exenteration surgery

AIM

This study aimed to investigate the implementation and pain-related outcomes of a peri-operative pain-management regimen for patients undergoing pelvic exenteration surgery at a university teaching hospital.

METHOD

This is a single-site prospective observational cohort study involving 100 patients who underwent pelvic exenteration surgery between January 2017 and December 2018. A pain-management algorithm regarding the use of opioid-sparing multimodal analgesia was developed between the departments of anaesthesia, pain management and intensive care. The primary outcomes were: compliance with a pain-treatment algorithm compared with a similar retrospective surgical patient cohort in 2013-2014; and requirements for regular doses of opioid analgesia at discharge, measured in oral morphine equivalent daily dose (oMEDD).

RESULTS

Following the introduction of a pain-management algorithm, regional anaesthesia techniques (spinal anaesthesia, transversus abdominus plane block, preperitoneal catheters or epidural analgesia) were used in 83/98 (84.7%) of the 2017-2018 cohort compared with 13/73 (17.8%) of the 2013-2014 cohort (p < 0.001). There was a reduction in the median dose of opioid analgesics (oMEDD) at time of discharge, from 150 mg (interquartile range [IQR]: 75.0-235.0 mg) in the 2013-2014 cohort to 10 mg (IQR: 0.00-45.0 mg) in the 2017-2018 cohort (p < 0.001). There was no change in pain intensity (assessed using the Verbal Numerical Rating Score) or oMEDD in the first 7 days following surgery.

CONCLUSION

Since implementation of a novel peri-operative pain-treatment algorithm, the use of opioid-sparing regional techniques and preperitoneal catheters has increased. Additionally, the dose of opioids required at the time of discharge has reduced significantly.

Comparing bupivacaine alone to liposomal bupivacaine plus bupivacaine in interscalene blocks for total shoulder arthroplasty: a randomized, non-inferiority trial

Introduction

Interscalene brachial plexus blocks are a commonly performed procedure to reduce pain following total shoulder arthroplasty. Liposomal bupivacaine has been purported to prolong the duration of brachial plexus blocks for up to 72 hours; however, there has been controversy surrounding the analgesic benefits of this drug. Our hypothesis was that an interscalene block performed with bupivacaine alone would be non-inferior to a combination of liposomal bupivacaine and bupivacaine with respect to opioid consumption following total shoulder arthroplasty.

Methods

Subjects presenting for primary total shoulder arthroplasty were randomized in a 1:1 ratio to an ultrasound-guided, single-injection interscalene block with either a combination of liposomal bupivacaine and bupivacaine (LB group) or bupivacaine without additive (Bupi group). The primary outcome of this study was 72-hour postoperative cumulative opioid consumption (in oral morphine equivalents) with a non-inferiority margin of 22.5 mg. Secondary outcomes included pain scores, patient satisfaction with analgesia and patient reported duration of sensory block.

Results

Seventy-six subjects, 38 from the Bupi group and 38 from the LB group, completed the study. Analysis of the primary outcome showed a 72-hour cumulative geometric mean oral morphine equivalent consumption difference of 11.9 mg (95% CI −6.9 to 30.8) between groups (calculated on the log scale). This difference constitutes approximately 1.5 tablets of oxycodone over 3 days. No secondary outcomes showed meaningful differences between groups.

Discussion

Interscalene brachial plexus blocks performed with bupivacaine alone did not demonstrate non-inferiority compared to a mixture of liposomal bupivacaine plus bupivacaine with regards to 72-hour cumulative opioid consumption following total shoulder arthroplasty. However, the difference between groups did not appear to be clinically meaningful.

Use and efficacy of virtual, augmented, or mixed reality technology for chronic pain: a systematic review

Aim: Characterize use and efficacy/effectiveness of virtual, augmented, or mixed reality (VR/AR/MR) technology as non-pharmacological therapy for chronic pain. Methods: Systematic search of 12 databases to identify empirical studies, of individuals who experience chronic pain or illness involving chronic pain, published between 1990 and 2021. JBI Critical Appraisal Checklists assessed study bias and a narrative synthesis was provided. Results: 46 studies, investigating a total of 1456 participants and including 19 randomized controlled trials (RCT), were reviewed. VR/AR/MR was associated with improved pain-related outcomes in 78% of the RCTs. Conclusion: While most studies showed effects immediately or up to one month post treatment, RCTs are needed to further evaluate VR/AR/MR, establish long-term benefits, and assess accessibility, especially among individuals who experience pain management disparities.

Efficacy and safety of intravenous acetaminophen (2 g/day) for reducing opioid consumption in Chinese adults after elective orthopedic surgery: A multicenter randomized controlled trial

Background: Acetaminophen is an important component of a multimodal analgesia strategy to reduce opioid consumption and pain intensity after an orthopedic surgery. The opioid-sparing efficacy of intravenous acetaminophen has been established at a daily dose of 4 g. However, it is still unclear for the daily dose of 2 g of acetaminophen, which is recommended by the China Food and Drug Administration Center for Drug Evaluation, in terms of its efficacy and safety.

Objectives: This study aimed to evaluate the efficacy and safety of intravenous acetaminophen at a daily dose of 2 g for reducing opioid consumption and pain intensity after orthopedic surgery.

Methods: In this multicenter, randomized, double-blind, placebo-controlled phase III trial, 235 patients who underwent orthopedic surgery were randomly assigned to receive intravenous acetaminophen 500 mg every 6 h or placebo. Postoperative morphine consumption, pain intensity at rest and during movement, and adverse events were analysed.

Results: For the mean (standard deviation) morphine consumption within 24 h after surgery, intravenous acetaminophen was superior to placebo both in the modified intention-to-treat analysis [8.7 (7.7) mg vs. 11.2 (9.2) mg] in the acetaminophen group and the placebo group, respectively. Difference in means: 2.5 mg; 95% confidence interval, 0.25 to 4.61; p = 0.030), and in the per-protocol analysis (8.3 (7.0) mg and 11.7 (9.9) mg in the acetaminophen group and the placebo group, respectively. Difference in means: 3.4 mg; 95% confidence interval: 1.05 to 5.77; p = 0.005). The two groups did not differ significantly in terms of pain intensity and adverse events.

Conclusion: Our results suggest that intravenous acetaminophen at a daily dose of 2 g can reduce morphine consumption by Chinese adults within the first 24 h after orthopedic surgery, but the extent of reduction is not clinically relevant.

Clinical Trial Registration: [ClinicalTrials.gov], identifier [NCT02811991].

Opioid versus opioid-free analgesia after surgical discharge: a systematic review and meta-analysis of randomised trials

BACKGROUND

Excessive opioid prescribing after surgery has contributed to the current opioid crisis; however, the value of prescribing opioids at surgical discharge remains uncertain. We aimed to estimate the extent to which opioid prescribing after discharge affects self-reported pain intensity and adverse events in comparison with an opioid-free analgesic regimen.

METHODS

In this systematic review and meta-analysis, we searched MEDLINE, Embase, the Cochrane Library, Scopus, AMED, Biosis, and CINAHL from Jan 1, 1990, until July 8, 2021. We included multidose randomised controlled trials comparing opioid versus opioid-free analgesia in patients aged 15 years or older, discharged after undergoing a surgical procedure according to the Physiological and Operative Severity Score for the Enumeration of Mortality and Morbidity definition (minor, moderate, major, and major complex). We screened articles, extracted data, and assessed risk of bias (Cochrane's risk-of-bias tool for randomised trials) in duplicate. The primary outcomes of interest were self-reported pain intensity on day 1 after discharge (standardised to 0-10 cm visual analogue scale) and vomiting up to 30 days. Pain intensity at further timepoints, pain interference, other adverse events, risk of dissatisfaction, and health-care reutilisation were also assessed. We did random-effects meta-analyses and appraised evidence certainty using the Grading of Recommendations, Assessment, Development, and Evaluations scoring system. The review was registered with PROSPERO (ID CRD42020153050).

FINDINGS

47 trials (n=6607 patients) were included. 30 (64%) trials involved elective minor procedures (63% dental procedures) and 17 (36%) trials involved procedures of moderate extent (47% orthopaedic and 29% general surgery procedures). Compared with opioid-free analgesia, opioid prescribing did not reduce pain on the first day after discharge (weighted mean difference 0·01cm, 95% CI -0·26 to 0·27; moderate certainty) or at other postoperative timepoints (moderate-to-very-low certainty). Opioid prescribing was associated with increased risk of vomiting (relative risk 4·50, 95% CI 1·93 to 10·51; high certainty) and other adverse events, including nausea, constipation, dizziness, and drowsiness (high-to-moderate certainty). Opioids did not affect other outcomes.

INTERPRETATION

Findings from this meta-analysis support that opioid prescribing at surgical discharge does not reduce pain intensity but does increase adverse events. Evidence relied on trials focused on elective surgeries of minor and moderate extent, suggesting that clinicians can consider prescribing opioid-free analgesia in these surgical settings. Data were largely derived from low-quality trials, and none involved patients having major or major-complex procedures. Given these limitations, there is a great need to advance the quality and scope of research in this field.

FUNDING

The Canadian Institutes of Health Research.

Opioid-sparing effect of cannabinoids for analgesia: an updated systematic review and meta-analysis of preclinical and clinical studies

Cannabinoid co-administration may enable reduced opioid doses for analgesia. This updated systematic review on the opioid-sparing effects of cannabinoids considered preclinical and clinical studies where the outcome was analgesia or opioid dose requirements. We searched Scopus, Cochrane Central Registry of Controlled Trials, Medline, and Embase (2016 onwards). Ninety-two studies met the search criteria including 15 ongoing trials. Meta-analysis of seven preclinical studies found the median effective dose (ED₅₀) of morphine administered with delta-9-tetrahydrocannabinol was 3.5 times lower (95% CI 2.04, 6.03) than the ED₅₀ of morphine alone. Six preclinical studies found no evidence of increased opioid abuse liability with cannabinoid administration. Of five healthy-volunteer experimental pain studies, two found increased pain, two found decreased pain and one found reduced pain bothersomeness with cannabinoid administration; three demonstrated that cannabinoid co-administration may increase opioid abuse liability. Three randomized controlled trials (RCTs) found no evidence of opioid-sparing effects of cannabinoids in acute pain. Meta-analysis of four RCTs in patients with cancer pain found no effect of cannabinoid administration on opioid dose (mean difference -3.8 mg, 95% CI -10.97, 3.37) or percentage change in pain scores (mean difference 1.84, 95% CI -2.05, 5.72); five studies found more adverse events with cannabinoids compared with placebo (risk ratio 1.13, 95% CI 1.03, 1.24). Of five controlled chronic non-cancer pain trials; one low-quality study with no control arm, and one single-dose study reported reduced pain scores with cannabinoids. Three RCTs found no treatment effect of dronabinol. Meta-analyses of observational studies found 39% reported opioid cessation (95% CI 0.15, 0.64, I² 95.5%, eight studies), and 85% reported reduction (95% CI 0.64, 0.99, I² 92.8%, seven studies). In summary, preclinical and observational studies demonstrate the potential opioid-sparing effects of cannabinoids in the context of analgesia, in contrast to higher-quality RCTs that did not provide evidence of opioid-sparing effects.

If the doors of perception were cleansed, would chronic pain be relieved? Evaluating the benefits and risks of psychedelics

Psychedelic substances have played important roles in diverse cultures, and ingesting various plant preparations to evoke altered states of consciousness has been described throughout recorded history. Accounts of the subjective effects of psychedelics typically focus on spiritual and mystical-type experiences, including feelings of unity, sacredness, and transcendence. Over the past two decades, there has been increasing interest in psychedelics as treatments for various medical disorders, including chronic pain. Although concerns about adverse medical and psychological effects contributed to their controlled status, contemporary knowledge of psychedelics suggests that risks are relatively rare when patients are carefully screened, prepared, and supervised. Clinical trial results have provided support for the effectiveness of psychedelics in different psychiatric conditions. However, there are only a small number of generally uncontrolled studies of psychedelics in patients with chronic pain (e.g., cancer pain, phantom limb pain, migraine, and cluster headache). Challenges in evaluating psychedelics as treatments for chronic pain include identifying neurobiologic and psychosocial mechanisms of action and determining which pain conditions to investigate. Truly informative proof-of-concept and confirmatory randomized clinical trials will require careful selection of control groups, efforts to minimize bias from unblinding, and attention to the roles of patient mental set and treatment setting. Perspective: There is considerable promise for the use of psychedelic therapy for pain, but evidence-based recommendations for the design of future studies are needed to ensure that the results of this research are truly informative.

Efficacy of interventions to reduce long term opioid treatment for chronic non-cancer pain: systematic review and meta-analysis

OBJECTIVE

To review interventions to reduce long term opioid treatment in people with chronic non-cancer pain, considering efficacy on dose reduction and discontinuation, pain, function, quality of life, withdrawal symptoms, substance use, and adverse events.

DESIGN

Systematic review and meta-analysis of randomised controlled trials and non-randomised studies of interventions.

DATA SOURCES

Medline, Embase, PsycINFO, CINAHL, and the Cochrane Library searched from inception to July 2021. Reference lists and previous reviews were also searched and experts were contacted.

ELIGIBILITY CRITERIA FOR STUDY SELECTION

Original research in English. Case reports and cross sectional studies were excluded.

DATA EXTRACTION AND SYNTHESIS

Two authors independently selected studies, extracted data, and used the Cochrane risk-of-bias tools for randomised and non-randomised studies (RoB 2 and ROBINS-I). Authors grouped interventions into five categories (pain self-management, complementary and alternative medicine, pharmacological and biomedical devices and interventions, opioid replacement treatment, and deprescription methods), estimated pooled effects using random effects meta-analytical models, and appraised the certainty of evidence using GRADE (grading of recommendations, assessment, development, and evaluation).

RESULTS

Of 166 studies meeting inclusion criteria, 130 (78%) were considered at critical risk of bias and were excluded from the evidence synthesis. Of the 36 included studies, few had comparable treatment arms and sample sizes were generally small. Consequently, the certainty of the evidence was low or very low for more than 90% (41/44) of GRADE outcomes, including for all non-opioid patient outcomes. Despite these limitations, evidence of moderate certainty indicated that interventions to support prescribers' adherence to guidelines increased the likelihood of patients discontinuing opioid treatment (adjusted odds ratio 1.5, 95% confidence interval 1.0 to 2.1), and that these prescriber interventions as well as pain self-management programmes reduced opioid dose more than controls (intervention v control, mean difference -6.8 mg (standard error 1.6) daily oral morphine equivalent, P<0.001; pain programme v control, -14.31 mg daily oral morphine equivalent, 95% confidence interval -21.57 to -7.05).

CONCLUSIONS

Evidence on the reduction of long term opioid treatment for chronic pain continues to be constrained by poor study methodology. Of particular concern is the lack of evidence relating to possible harms. Agreed standards for designing and reporting studies on the reduction of opioid treatment are urgently needed.

REVIEW REGISTRATION

PROSPERO CRD42020140943.