Systematic Review and Meta-Analysis of the Prevalence of Chronic Pain Among Patients With Opioid Use Disorder and Receiving Opioid Substitution Therapy

Associations Among Sleep, Pain, and Medications for Opioid Use Disorder: a Scoping Review

Purpose of Review

We present current evidence on the associations among sleep, pain, and medications for opioid use disorder (MOUD) among individuals with opioid use disorder (OUD).

Recent Findings

We searched MEDLINE, Embase, PsycInfo, Web of Science, and Cochrane Library from inception until September 2023 for original research studies examining sleep, pain, and MOUD. We identified 19 manuscripts (14 were cross-sectional studies, four were prospective cohort studies, and one was a randomized controlled trial). Measures of sleep and pain varied. Sleep disturbance and pain were highly prevalent and associated. However, the associations between MOUD treatment characteristics (e.g., initiation, type, dose, and prior MOUD) and a) sleep and b) pain were mixed or unclear. Limited sample sizes and covariates such as opioid use disorder severity sometimes complicated the examination or interpretation of these associations. Few studies examined possible mediators underlying these associations.

Summary

While sleep and pain were consistently associated, it is unclear whether sleep and pain are associated with MOUD treatment characteristics or other covariates such as opioid use disorder severity. Future research on the associations among sleep, pain, and MOUD among individuals with OUD should consider a) comparing different MOUD treatments including formulations and dose schedules, b) qualitative and mixed methods studies to assess patient and provider preferences for the treatment of sleep and pain in OUD treatment settings, c) longitudinal studies that employ reliable and valid measures with sufficiently powered sample sizes to examine mediation and moderation, and d) testing whether interventions addressing pain or sleep among patients receiving MOUD improve pain, sleep, and MOUD outcomes.

From taboo to treatment: The emergence of psychedelics in the management of pain and opioid use disorder

The rise of psychedelics in contemporary medicine has sparked interest in their potential therapeutic applications. While traditionally associated with countercultural movements and recreational use, recent research has shed light on the potential benefits of psychedelics in various mental health conditions. In this review, we explore the possible role of psychedelics in the management of chronic pain and opioid use disorder (OUD), 2 critical areas in need of innovative treatment options. Pain control remains a significant clinical challenge, particularly for individuals with OUD and those who receive long-term opioid therapy who develop marked tolerance to opioid-induced analgesia. Despite the magnitude of this problem, there is a scarcity of controlled studies investigating pain management alternatives for these populations. Drawing from preclinical and human evidence, we highlight the potential of psychedelics to act on shared neurobiological substrates of chronic pain and OUD, potentially reversing pain- and opioid-induced neuroadaptations, such as central sensitization. We elaborate on the multifaceted dimensions of the pain experience (sensory, affective and cognitive) and their intersections that overlap with opioid-related phenomena (opioid craving and withdrawal), hypothesizing how these processes can be modulated by psychedelics. After summarizing the available clinical research, we propose mechanistic insights and methodological considerations for the design of future translational studies and clinical trials, building on a shared clinical and neurobiological understanding of chronic pain and OUD. Our intention is to provide timely perspectives that accelerate the development and exploration of novel therapeutics for chronic pain and OUD amidst the escalating opioid crisis.

Assessing pain in persons with opioid use disorder: Approaches, techniques and special considerations

Pain and opioid use disorder (OUD) are inextricably linked, as the former can be a risk factor for the development of the latter, and over a third of persons with OUD suffer concomitant chronic pain. Assessing pain among people with OUD is challenging, because ongoing opioid use brings changes in pain responses and most pain assessment tools have not been validated for this population. In this narrative review, we discuss the fundamentals of pain assessment for populations with OUD. First, we describe the biological, psychological and social aspects of the pain experience among people with OUD, as well as how opioid-related phenomena may contribute to the pain experience in this population. We then review methods to assess pain, including (1) traditional self-reported methods, such visual analogue scales and structured questionnaires; (2) behavioural observations and physiological indicators; (3) and laboratory-based approaches, such as quantitative sensory testing. These methods are considered from a perspective that encompasses both pain and OUD. Finally, we discuss strategies for improving pain assessment in persons with OUD and implications for future research, including educational strategies for multidisciplinary teams. We highlight the substantial gaps that persist in this literature, particularly regarding the applicability of current pain assessment methods to persons with OUD, as well as the generalizability of the existing results from adjacent populations on chronic opioid therapy but without OUD. As research linking pain and OUD evolves, considering the needs of diverse populations with complex psychosocial backgrounds, clinicians will be better equipped to reduce these gaps.

Glial modulators as novel therapeutics for comorbid pain and opioid use disorder

Chronic pain and opioid use disorder (OUD) are major public health problems, with rising opioid-related overdose deaths linked to increased opioid prescriptions for pain management. Novel treatment approaches for these commonly comorbid disorders are needed. Growing evidence supports a role for glial activation for both chronic pain and substance use disorders, including OUD. This review provides an overview of glial modulators as a novel treatment approach for comorbid pain and OUD. We aim to synthesize clinical studies investigating the efficacy of glial modulators in treating these comorbid disorders. We conducted a literature search of PubMed and Google Scholar databases in October 2023 to identify relevant clinical trials. The included studies varied in terms of patient population, study methodology and outcomes assessed, and were often limited by small sample sizes and other methodological issues. Additionally, several glial modulators have yet to be studied for chronic pain and OUD. Despite these limitations, these studies yielded positive signals that merit further investigation. Both chronic pain and OUD remain significant public health problems, with many treatment challenges. Glial modulators continue to hold promise as novel therapeutics for comorbid pain and OUD, given positive indications that they can improve pain measures, and reduce addiction-related outcomes. As our understanding of the mechanisms underlying the contributions of glial modulators to pain and addiction behaviours deepens, we will be better equipped to identify more specific therapeutic targets for chronic pain and OUD.

Pain in people seeking and receiving opioid agonist treatment: A systematic review and meta-analysis of prevalence and correlates

BACKGROUND AND AIMS

People with opioid use disorder (OUD) commonly experience pain including chronic pain. Despite the high prevalence, few studies have systematically examined the prevalence and correlates of pain among people seeking or receiving opioid agonist treatment (OAT) for OUD. This review aimed to determine the prevalence of pain in this population globally, and estimate the association between chronic pain and other demographic and clinical characteristics.

METHODS

Electronic searches were conducted in three databases (Medline, Embase and PsycINFO) from the inception until October 2022. Eligible studies reported prevalence rates of current and/or chronic pain. Meta-analyses examining the main prevalence estimates were conducted by Stata SE 18.0, and comorbid clinical conditions were analysed by Review Manager 5.4.

RESULTS

Fifty-six studies (n participants = 35 267) from sixty-seven publications were included. Prevalence estimates of current and chronic pain were reported in 27 (48.2%) and 40 studies (71.4%), respectively. Most studies were conducted in North America (71.4%, n = 40) and used cross-sectional designs (64.3%, n = 36). Meta-analyses revealed a pooled prevalence of 60.0% (95% confidence interval [CI]: 52.0-68.0) for current pain and 44.0% [95% CI: 40.0-49.0] for chronic pain. Chronic pain was positively associated with older age (mean deviation of mean age: 2.39 years, 95% CI: 1.40-3.37; I2 = 43%), unemployment (odds ratio [OR] = 0.57, 95% CI: 0.42-0.76; I2 = 78%), more severe mental health symptoms (e.g. more severe depression (standardised mean difference [SMD] of mean scores: 0.45, 95% CI: 0.20-0.70; I2 = 48%) and anxiety symptoms (SMD: 0.52, 95% CI: 0.17-0.88; I2 = 67%), and hepatitis C (OR = 1.41, 95% CI: 1.03-1.94; I2 = 0%). No association was observed between chronic pain and the onset and type of OAT, geographic location, study design, survey year, participant age or use of specific pain assessment tools.

CONCLUSIONS

There appears to be a high prevalence of pain among people seeking or receiving opioid agonist treatment for opioid use disorder compared with the general population, with positive associations for older age, unemployment, hepatitis C and the severity of some mental health symptoms.

Hyperalgesia in Patients With a History of Opioid Use Disorder: A Systematic Review and Meta-Analysis

Importance

Short-term and long-term opioid treatment have been associated with increased pain sensitivity (ie, opioid-induced hyperalgesia). Treatment of opioid use disorder (OUD) mainly involves maintenance with methadone and buprenorphine, and observations of heightened cold pain sensitivity among patients are often considered evidence of opioid-induced hyperalgesia.

Objective

To critically examine the evidence that hyperalgesia in patients with OUD is related to opioid use.

Data Sources

Web of Science, PubMed, and Embase between March 1, 2023, and April 12, 2024, were searched.

Study Selection

Studies assessing cold pressor test (CPT) pain responses during treatment seeking, pharmacological treatment, or abstinence in patients with OUD history were included.

Data Extraction and Synthesis

Multilevel random-effects models with robust variance estimation were used for all analyses. Study quality was rated with the JBI checklist. Funnel plots and Egger regression tests were used to assess reporting bias.

Main Outcomes and Measures

Main outcomes were pain threshold, tolerance, and intensity in patients and healthy controls, and unstandardized, standardized (Hedges g), and percentage differences (%Δ) in these measures between patients and controls. The association between pain sensitivity and opioid tolerance, withdrawal, and abstinence indices was tested with meta-regression.

Results

Thirty-nine studies (1385 patients, 741 controls) met the inclusion criteria. Most studies reported CPT data on patients undergoing opioid agonist treatment. These patients had a mean 2- to 3-seconds lower pain threshold (95% CI, -4 to -1; t test P = .01; %Δ, -22%; g = -0.5) and 29-seconds lower pain tolerance (95% CI, -39 to -18; t test P < .001; %Δ, -52%; g = -0.9) than controls. Egger tests suggested that these differences may be overestimated. There were some concerns of bias due to inadequate sample matching and participant dropout. Meta-regressions yielded no clear support for hyperalgesia being opioid related.

Conclusion and Relevance

Patients receiving opioid agonist treatment for OUD are hypersensitive to cold pain. It remains unclear whether hyperalgesia develops prior to, independent of, or as a result of long-term opioid treatment. Regardless, future studies should investigate the impact of hyperalgesia on patients' well-being and treatment outcomes.

Characteristics of patients who are initiated on long-acting buprenorphine (Buvidal®) in France: A retrospective cross-sectional study

AIM

The long-acting buprenorphine Buvidal® is a recent type of opioid agonist treatment (OAT) used for opioid use disorder (OUD). It was initially suggested to preferentially use Buvidal® for specific OUD populations, including people in prison, or patients in recovery and on sublingual buprenorphine. We conducted a national study to examine whether the profile of patients treated with Buvidal® in France matched these initial recommendations.

METHODS

A retrospective cross-sectional study was conducted in 13 national addiction centers (outside prison), using the individual medical records of patients initiated on Buvidal®. Baseline characteristics were collected and described, including sociodemographic features, comorbid medical conditions, concurrent substance use and prescription drug misuse, and OAT features before Buvidal® initiation, respectively.

RESULTS

In total 101 patients (72.3% males, mean age 43.9±11.3years) were identified, which corresponded to one sixth of all patients treated with Buvidal® in France at the time of the study. Of them, 36 (36.4%) of them were professionally active, 35 (35.4%) were durably inactive, and the rest in an intermediary situation. Furthermore, 90 (90.0%) patients had at least one medical comorbidity (all types), and 83 (83.0%) at least one psychiatric comorbidity. Most frequent non-psychiatric comorbidities were chronic pain (n=20, 20.0%) and chronic viral infection (n=16, 17.8%). Current use of psychoactive substances included cocaine and crack (n=43, 42.6%), heroin (n=19, 18.8%), but also misuse of prescription drugs (n=20, 20%), mainly opioid analgesics. Moreover, 99 (98.0%) patients had an OAT before Buvidal® initiation, including 7 (8.1%) patients on methadone.

CONCLUSION

The profile of patients initiated on Buvidal® in France was extremely similar to that of patients treated for OUD in France, either in terms of social or clinical features. While initial recommendations essentially underlined the interest of Buvidal® for some niche populations, the on-the-ground practice reveals a more widespread use, including for unrecovered patients, or patients treated with methadone.

Unveiling the link between chronic pain and misuse of opioids and cannabis

Over 50 million Americans endure chronic pain where many do not receive adequate treatment and self-medicate to manage their pain by taking substances like opioids and cannabis. Research has shown high comorbidity between chronic pain and substance use disorders (SUD) and these disorders share many common neurobiological underpinnings, including hypodopaminergic transmission. Drugs commonly used for self-medication such as opioids and cannabis relieve emotional, bothersome components of pain as well as negative emotional affect that perpetuates misuse and increases the risk of progressing towards drug abuse. However, the causal effect between chronic pain and the development of SUDs has not been clearly established. In this review, we discuss evidence that affirms the proposition that chronic pain is a risk factor for the development of opioid and cannabis use disorders by outlining the clinical evidence and detailing neurobiological mechanisms that link pain and drug misuse. Central to the link between chronic pain and opioid and cannabis misuse is hypodopaminergic transmission and the modulation of dopamine signaling in the mesolimbic pathway by opioids and cannabis. Moreover, we discuss the role of kappa opioid receptor activation and neuroinflammation in the context of dopamine transmission, their contribution to opioid and cannabis withdrawal, along with potential new treatments.

Denial of prescription pain medication among people who use drugs in Vancouver, Canada

BACKGROUND

People who use drugs experience pain at two to three times the rate of the general population and yet continue to face substantial barriers to accessing appropriate and adequate treatment for pain. In light of the overdose crisis and revised opioid prescribing guidelines, we sought to identify factors associated with being denied pain medication and longitudinally investigate denial rates among people who use drugs.

METHODS

We used multivariable generalized estimating equations analyses to investigate factors associated with being denied pain medication among people who use drugs reporting pain in three prospective cohort studies in Vancouver, Canada. Analyses were restricted to study periods in which participants requested a prescription for pain from a healthcare provider. Descriptive statistics detail denial rates and actions taken by participants after being denied.

RESULTS

Among 1168 participants who requested a prescription for pain between December 2012 and March 2020, the median age was 47 years and 63.0% were male. Among 4,179 six-month observation periods, 907 (21.7%) included a report of being denied requested pain medication. In multivariable analyses, age was negatively associated with prescription denial (adjusted odds ratio [AOR] = 0.98, 95% confidence interval [CI]:0.97-0.99), while self-managing pain (AOR = 2.48, 95%CI:2.04-3.00), experiencing a non-fatal overdose (AOR = 1.51, 95%CI:1.22-1.88), engagement in opioid agonist therapy (AOR = 1.32, 95%CI:1.09-1.61), and daily use of heroin or other unregulated opioids (AOR = 1.32, 95%CI:1.05-1.66) were positively associated with being denied. Common actions taken (n = 895) after denial were accessing the unregulated drug supply (53.5%), doing nothing (30.6%), and going to a different doctor/emergency room (6.1%). The period following the introduction of new prescribing guidelines was not associated with a change in denial rates.

CONCLUSIONS

A substantial proportion of people who use drugs continue to be denied prescriptions for pain, with such denial associated with important substance use-related harms, including non-fatal overdose. Guidelines specific to the pharmaceutical management of pain among people who use drugs are needed.

Case report: Successful induction of buprenorphine in medically complex patients concurrently on opioids: a case series at a tertiary care center

Effective pain management is essential for optimal surgical outcomes; however, it can be challenging in patients with a history of opioid use disorder (OUD). Buprenorphine, a partial opioid agonist, is a valuable treatment option for patients with OUD. Initiating buprenorphine treatment in patients concurrently taking opioids can be complex due to potential adverse outcomes like precipitated withdrawal. Evolving guidelines suggest there are benefits to continuing buprenorphine for surgical patients throughout the perioperative period, however situations do arise when buprenorphine has been discontinued. Typically, in this scenario patients would be restarted on buprenorphine after they have fully recovered from post-surgical pain and no longer require opioids for pain control. Unfortunately, holding MOUD may expose the patient to risks such as opioid induced respiratory depression or addiction relapse. In this case series, we discuss a novel method to restart buprenorphine in small incremental doses, known as micro-dosing, while the patient is still taking opioids for pain. We will present two complex clinical cases when this method was used successfully at a tertiary care hospital system.

Considerations and limitations of buprenorphine prescribing for opioid use disorder in the intensive care unit setting: A narrative review

PURPOSE

The purpose of this review is to discuss important considerations when prescribing buprenorphine for opioid use disorder (OUD) in the intensive care unit (ICU) setting, recognizing the challenges of providing detailed recommendations in the setting of limited available evidence.

SUMMARY

Buprenorphine is a partial mu-opioid receptor agonist that is likely to be increasingly prescribed for OUD in the ICU setting due to the relaxation of prescribing regulations. The pharmacology and pharmacokinetics of buprenorphine are complicated by the availability of several formulations that can be given by different administration routes. There is no single optimal dosing strategy for buprenorphine induction, with regimens ranging from very low-dose to high dose regimens. Faster induction with higher doses of buprenorphine has been studied and is frequently utilized in the emergency department. In patients admitted to the ICU who were receiving opioids either medically or illicitly, analgesia will not occur until their baseline opioid requirements are covered when their preadmission opioid is either reversed or interrupted. For patients in the ICU who are not on buprenorphine at the time of admission but have possible OUD, there are no validated tools to diagnose OUD or the severity of opioid withdrawal in critically ill patients unable to provide the subjective components of instruments validated in outpatient settings. When prescribing buprenorphine in the ICU, important issues to consider include dosing, monitoring, pain management, use of adjunctive medications, and considerations to transition to outpatient therapy. Ideally, addiction and pain management specialists would be available when buprenorphine is prescribed for critically ill patients.

CONCLUSION

There are unique challenges when prescribing buprenorphine for OUD in critically ill patients, regardless of whether they were receiving buprenorphine when admitted to the ICU setting for OUD or are under consideration for buprenorphine initiation. There is a critical need for more research in this area.

Evaluation of intervention components to maximize yoga practice among people with chronic pain taking opioid agonist therapy: A factorial experiment using the multiphase optimization strategy framework

BACKGROUND

Chronic pain affects up to half of individuals taking opioid agonist therapy (OAT; i.e., methadone and buprenorphine) for opioid use disorder (OUD), and yoga-based interventions may be useful for decreasing pain-related disability. Whereas more yoga practice (i.e., higher "dosage") may improve pain-related outcomes, it can be challenging for people with chronic pain taking OAT to attend class regularly and sustain a regular personal yoga practice. Therefore, we plan to optimize a yoga-based intervention (YBI) package in order to support class attendance and personal practice, thus maximizing the yoga dose received.

STUDY DESIGN

Using the Multiphase Optimization Strategy (MOST) framework, we will conduct a factorial experiment to examine four intervention components that may be added to a weekly yoga class as part of a YBI. Components include: 1) personal practice videos featuring study yoga teachers, 2) two private sessions with a yoga teacher, 3) daily text messages to inspire personal practice, and 4) monetary incentives for class attendance. The primary outcome will be minutes per week engaged in yoga (including class attendance and personal practice). We plan to enroll 192 adults with chronic pain who are taking OAT for OUD in this 2x2x2x2 factorial experiment.

CONCLUSION

Results of the study will guide development of an optimized yoga-based intervention package that maximizes dosage of yoga received. The final treatment package can be tested in a multisite efficacy trial of yoga to reduce pain interference in daily functioning in people with chronic pain who are taking OAT.

TRIAL REGISTRATION

Pre-registration of the study was completed on ClinicalTrials.gov (identifier: NCT04641221).

Utilization and disparities in medication treatment for opioid use disorder among patients with comorbid opioid use disorder and chronic pain during the COVID-19 pandemic

BACKGROUND

The COVID-19 pandemic's impact on utilization of medications for opioid use disorder (MOUD) among patients with opioid use disorder (OUD) and chronic pain is unclear.

METHODS

We analyzed New York State (NYS) Medicaid claims from pre-pandemic (August 2019-February 2020) and pandemic (March 2020-December 2020) periods for beneficiaries with and without chronic pain. We calculated monthly proportions of patients with OUD diagnoses in 6-month-lookback windows utilizing MOUD and proportions of treatment-naïve patients initiating MOUD. We used interrupted time series to assess changes in MOUD utilization and initiation rates by medication type and by race/ethnicity.

RESULTS

Among 20,785 patients with OUD and chronic pain, 49.3% utilized MOUD (versus 60.3% without chronic pain). The pandemic did not affect utilization in either group but briefly disrupted initiation among patients with chronic pain (β=-0.009; 95% CI [-0.015, -0.002]). Overall MOUD utilization was not affected by the pandemic for any race/ethnicity but opioid treatment program (OTP) utilization was briefly disrupted for non-Hispanic Black individuals (β=-0.007 [-0.013, -0.001]). The pandemic disrupted overall MOUD initiation in non-Hispanic Black (β=-0.007 [-0.012, -0.002]) and Hispanic individuals (β=-0.010 [-0.019, -0.001]).

CONCLUSIONS

Adults with chronic pain who were enrolled in NYS Medicaid before the COVID-19 pandemic had lower MOUD utilization than those without chronic pain. MOUD initiation was briefly disrupted, with disparities especially in racial/ethnic minority groups. Flexible MOUD policy initiatives may have maintained overall treatment utilization, but disparities in initiation and care continuity remain for patients with chronic pain, and particularly for racial/ethnic minoritized subgroups.