Exploring the relationship between perceived inter-dose opioid withdrawal and patient characteristics in methadone maintenance treatment

Discordance between pain specialists and patients on the perception of dependence on pain medication: A multi-centre cross-sectional study

AIM

Patients with chronic non-cancer pain are referred to pain centres to improve their pain treatment. The discontinuation of pain medications in case of poor efficacy can be difficult to accept for patients, particularly opioid analgesics. Previous research has described that from the patients' perspective, the psychological relief of a negative effect of chronic pain and withdrawal symptoms of prescription opioids represent drivers of persistent use and first stage of opioid use disorder, despite insufficient pain relief. There is no validated tool to investigate this psychological dependence. This study aimed to assess discordance between patients and pain specialists in their perception of dependence on pain medication and investigate associations with characteristics of patients, type of pain and iatrogenic pharmacodependence.

METHODS

Self-administered questionnaires (patients and physicians) were administered in six pain centres in France. A question on perceived dependence on pain medications was addressed to the patient and the physician in a matched pair. Discordance between them was evaluated by the Cohen kappa coefficient. Demographics, pain, anxiety and depression, pain medication withdrawal symptoms, diverted use, and craving represented variables studied in a multivariate model as potentially associated with patient-physician discordance.

RESULTS

According to the 212 pairs of completed questionnaires, a perceived dependence was reported by the majority of patients (65.6%) and physicians (68.4%). However, the concordance was fair (kappa=0.38; CI [95%]: 0.25-0.51). Almost all patients (89.3%) were treated with an opioid analgesic. A higher likelihood of discordance was observed when patients suffered from nociplastic pain (odds ratio [OR]: 2.72, 95% [CI]: 1.29-5.84).

CONCLUSION

Medical shared-decision for changing pain treatment could be improved by taking into account the perception of patient dependence on medications for pain relief and or psychoactive effects, particularly in nociplastic pain for which the treatment is challenging.

The relationship of pain intensity and opioid craving with delayed methadone dose: A preliminary study of individuals with opioid use disorder

AIMS

Despite a strong theoretical link between opioid craving and pain, little is known about the temporal relationship between pain and craving and the acute experience of pain in the context of methadone treatment. Using a cross-over design, the current study evaluated the time course of pain and craving and objective experience of pain as a function of the last methadone dose.

METHODS

Participants (n = 20) presented for the study in the morning and either received methadone dose as scheduled or delayed dose until the afternoon. During the 4-h study visit, participants completed a series of tasks, including repeated assessment of pain and craving at 0, +40, +70, +130, +160 and +240 min and a cold pressor test (CPT) at +15 and +220 min.

RESULTS

Separate mixed model results demonstrated no effect of dosing condition on craving; however, there was a significant dosing condition by time interaction (F(5,209) = 3.38, P = .006) such that pain increased over time in the delayed methadone condition but decreased in time in the scheduled methadone condition. A mixed model predicting self-reported pain revealed a three-way interaction between dosing condition, craving and time (F(5,197) = 2.39, P = .039) explained by a positive association between craving and pain at each time point (except 240 min) in delayed condition (P-range = .004-.0001). A separate mixed model on CPT data indicated a significant condition by time interaction such that pain threshold decreased in the delayed, but not scheduled, condition (F(1,57) = 4.01, P = .050).

CONCLUSIONS

These preliminary findings highlight the potential for increased risks after even a short delay in receiving a methadone dose.

Optimizing methadone dose adjustment in patients with opioid use disorder

Introduction

Opioid use disorder is a cause for concern globally. This study aimed to optimize methadone dose adjustments using mixed modeling and machine learning.

Methods

This retrospective study was conducted at Taichung Veterans General Hospital between January 1, 2019, and December 31, 2020. Overall, 40,530 daily dosing records and 1,508 urine opiate test results were collected from 96 patients with opioid use disorder. A two-stage approach was used to create a model of the optimized methadone dose. In Stage 1, mixed modeling was performed to analyze the association between methadone dose, age, sex, treatment duration, HIV positivity, referral source, urine opiate level, last methadone dose taken, treatment adherence, and likelihood of treatment discontinuation. In Stage 2, machine learning was performed to build a model for optimized methadone dose.

Results

Likelihood of discontinuation was associated with reduced methadone doses (β = 0.002, 95% CI = 0.000-0.081). Correlation analysis between the methadone dose determined by physicians and the optimized methadone dose showed a mean correlation coefficient of 0.995 ± 0.003, indicating that the difference between the methadone dose determined by physicians and that determined by the model was within the allowable range (p < 0.001).

Conclusion

We developed a model for methadone dose adjustment in patients with opioid use disorders. By integrating urine opiate levels, treatment adherence, and likelihood of treatment discontinuation, the model could suggest automatic adjustment of the methadone dose, particularly when face-to-face encounters are impractical.

Day-to-day opioid withdrawal symptoms, psychological distress, and opioid craving in patients with chronic pain prescribed opioid therapy

BACKGROUND

Research has shown that opioid craving is one of the strongest determinants of opioid misuse in patients with chronic pain. To date, however, little is known on the factors that contribute to opioid craving in these patients. It is possible that patients' physical dependence to opioids, manifested by opioid withdrawal symptoms in between daily opioid doses, contribute to opioid craving. Physical dependence symptoms might also lead to psychological distress, which in turn might contribute to opioid craving. The first objective of this study was to examine the day-to-day association between opioid withdrawal symptoms and opioid craving among patients with chronic pain. We also examined whether negative affect and catastrophic thinking mediated this association.

METHODS

In this longitudinal study, chronic pain patients (n = 79) prescribed short-acting opioids completed daily diaries for 14 consecutive days. Diaries assessed a host of pain, psychological, and opioid-related variables.

RESULTS

Day-to-day elevations in opioid withdrawal symptoms were associated with heightened opioid craving (p < .001). Results of a multilevel mediation analysis revealed that this association was mediated by patients' daily levels of negative affect and catastrophizing (p < .001).

CONCLUSIONS

Our study provides valuable new insights into our understanding of factors that may contribute to prescription opioid craving among patients with chronic pain.

Clinical and psychological factors associated with interdose opioid withdrawal in chronic pain population

BACKGROUND

The DSM-5 diagnostic criteria for Prescription Opioid-Use Disorder (POUD) have undergone some significant changes. One of the most controversial changes has been the elimination of the withdrawal symptoms criterion when opioid use is under appropriate medical supervision. For this reason, the goal of this study was to analyze factors associated with opioid withdrawal in patients with chronic non-cancer pain (CNCP).

METHODS

This cross-sectional descriptive study involved 404 patients who use prescription opioids for long-term treatment (≥90 days) of CNCP. Measures included sociodemographic and clinical characteristics, POUD, withdrawal symptoms, craving, anxiety-depressive symptoms, and pain intensity and interference.

RESULTS

Forty-seven percent (n = 193) of the sample reported moderate-severe withdrawal symptoms, which were associated with lower age, higher daily morphine dose and duration of treatment with opioids, moderate-severe POUD, use of psychotropic drugs, higher anxiety-depressive symptoms, and greater pain intensity and interference (p < .05). Binary logistic regression analysis showed that moderate-severe POUD (OR = 2.82), anxiety (OR = 2.21), depression (OR = 1.81), higher pain interference (OR = 1.05), and longer duration of treatment with opioids were the strongest factors associated with moderate-severe withdrawal symptoms (p < .05).

CONCLUSION

Psychological factors seem to play a key role in the severity of withdrawal symptoms. Since greater intensity of these symptoms increases the risk of developing POUD, knowing the factors associated with withdrawal may be useful in developing preventive psychological interventions.

Exploring the use of extended release opioids at shortened dosing intervals in people with chronic pain and high risk medication or substance use

Background Critical attention to rational opioid prescribing has emerged from the opioid epidemic in North America. Individuals with chronic pain are prescribed extended release opioids in an effort to maintain stable drug levels and for more convenient dosing, though evidence to support improvements in pain or function is lacking. It has been observed that extended release opioid products are used at intervals shorter than recommended by product monographs. The need for shortened intervals has been linked with potential inter-patient variability in pharmacokinetics, among other rationale. Implications of shortened dosing intervals for extended release opioids have not been systematically studied. Objective The aim of this study was to characterize the use of extended release opioid formulations at shortened dosing intervals in a population of patients with chronic pain and high risk for opioid-related harms. Setting This study took place in the Interprofessional Pain and Addiction Recovery Clinic, a specialty ambulatory clinic at the Centre for Addiction and Mental Health in Toronto, Canada for adults with chronic pain and a diagnosis or suspicion of substance use disorder. Method This was a retrospective cross-sectional study. Data were collected from records of patients with assessments completed in the years 2012-2017 (n = 210). Main outcome measure Proportion of patients using extended release opioids at shortened intervals. Results Sixty-one percent of individuals using extended release opioids (n = 78) were using them at shortened intervals. This use was associated with a higher daily morphine equivalent dose (533 mg vs 236 mg, p < 0.01), use of oxycodone extended release products (50% vs. 27%, p < 0.01), a longer duration of opioid therapy (8.9 vs. 6.8 years, p = 0.03) and a diagnosis of chronic neuropathic pain (63% vs. 39%, p < 0.01), with no differences in reported pain intensities, compared with use at standard intervals. Conclusion The use of extended release opioids at shortened intervals was associated with increased daily morphine equivalent doses, thus an increased risk of opioid-related mortality. It is unlikely that of those using extended release opioids, the high proportion of use at shortened intervals is the result of inter-patient differences in metabolism alone. Further study is warranted to explore the underlying drivers and implications for people with chronic pain.

Craving and opioid use disorder: A scoping review

INTRODUCTION

The subjective experience of drug craving is a prominent and common clinical phenomenon for many individuals diagnosed with opioid use disorder (OUD), and could be a valuable clinical endpoint in medication development studies. The purpose of this scoping review is to provide an overview and critical analysis of opioid craving assessments located in the published literature examining OUD.

METHOD

Studies were identified through a search of PubMed, Embase, and PsychInfo databases and included for review if opioid craving was the focus and participants were diagnosed with or in treatment for OUD.

RESULTS

Fifteen opioid craving assessment instruments were identified across the 87 studies included for review. The most common were the Visual Analog Scale (VAS, 41 studies), Desires for Drug Questionnaire (DDQ, 12 studies), Heroin Craving Questionnaire (HCQ, 10 studies), and Obsessive-Compulsive Drug Use Scale (OCDUS, 10 studies). Craving assessments varied considerably in their format, content, time frame, and underlying subscales, and only 6 of 15 had been psychometrically evaluated.

DISCUSSION

This review identified a variety of opioid craving assessments, but few had been evaluated for their psychometric properties making it difficult to ascertain whether craving is being assessed optimally in studies of OUD. Thus, the development of a reliable and valid opioid craving assessment would be worthwhile and could be guided by recently published Food and Drug Administration Clinical Outcome Assessment (COA) guidelines. Importantly, a COA focused on opioid craving could be a valuable addition to research studies designed to evaluate novel treatments for OUD.

Rationale for cannabis-based interventions in the opioid overdose crisis

Background

North America is currently in the grips of a crisis rooted in the use of licit and illicit opioid-based analgesics. Drug overdose is the leading cause of accidental death in Canada and the US, and the growing toll of opioid-related morbidity and mortality requires a diversity of novel therapeutic and harm reduction-based interventions. Research suggests that increasing adult access to both medical and recreational cannabis has significant positive impacts on public health and safety as a result of substitution effect. Observational and epidemiological studies have found that medical cannabis programs are associated with a reduction in the use of opioids and associated morbidity and mortality.

Aims and Methods

This paper presents an evidence-based rationale for cannabis-based interventions in the opioid overdose crisis informed by research on substitution effect, proposing three important windows of opportunity for cannabis for therapeutic purposes (CTP) to play a role in reducing opioid use and interrupting the cycle towards opioid use disorder: 1) prior to opioid introduction in the treatment of chronic pain; 2) as an opioid reduction strategy for those patients already using opioids; and 3) as an adjunct therapy to methadone or suboxone treatment in order to increase treatment success rates. The commentary explores potential obstacles and limitations to these proposed interventions, and as well as strategies to monitor their impact on public health and safety.

Conclusion

The growing body of research supporting the medical use of cannabis as an adjunct or substitute for opioids creates an evidence-based rationale for governments, health care providers, and academic researchers to consider the implementation and assessment of cannabis-based interventions in the opioid crisis.

Psychological and physiological stress negatively impacts early engagement and retention of opioid-dependent individuals on methadone maintenance

The present study investigated whether psychological and/or physiological measures of stress would impede induction onto methadone maintenance and predict early (<6 months) discontinuation. Compared with controls, opioid-dependent subjects displayed increased distress on the perceived stress scale (PSS) and post-traumatic stress disorder checklist (PCLC); 60% exhibited abnormal cortisol. Addiction severity index (ASI), drug-use, and stress indices explained between 17 and 37% of the variance in engagement including attendance, opioid abstinence, and methadone stabilization. Participants who discontinued treatment displayed poor engagement, abnormal cortisol, elevated withdrawal symptoms, higher distress, and increased ongoing opioid use versus compliant individuals. Discontinuation was initially related to drug-use severity; however, by 6 months, retention depended primarily upon cortisol abnormalities, which increased an individual's discontinuation risk by 7.7-fold. These findings support admission screening with the ASI/cortisol for drop out, and stress/drug-use indices for engagement that together may enable clinically-relevant early recognition and interventions for prevention of stress-induced relapse in opioid-dependent populations.

Impact of cannabis use during stabilization on methadone maintenance treatment

BACKGROUND AND OBJECTIVES

Illicit drug use, particularly of cannabis, is common among opiate-dependent individuals and has the potential to impact treatment in a negative manner.

METHODS

To examine this, patterns of cannabis use prior to and during methadone maintenance treatment (MMT) were examined to assess possible cannabis-related effects on MMT, particularly during methadone stabilization. Retrospective chart analysis was used to examine outpatient records of patients undergoing MMT (n = 91), focusing specifically on past and present cannabis use and its association with opiate abstinence, methadone dose stabilization, and treatment compliance.

RESULTS

Objective rates of cannabis use were high during methadone induction, dropping significantly following dose stabilization. History of cannabis use correlated with cannabis use during MMT but did not negatively impact the methadone induction process. Pilot data also suggested that objective ratings of opiate withdrawal decrease in MMT patients using cannabis during stabilization.

CONCLUSIONS AND SCIENTIFIC SIGNIFICANCE

The present findings may point to novel interventions to be employed during treatment for opiate dependence that specifically target cannabinoid-opioid system interactions.

[Evaluation of the Methadone Maintenance Program of the Risaralda Mental Hospital]

BACKGROUND

Psychosocial care and methadone maintenance treatment (MMT) are the preferred strategies for the management of heroin addicts, but the results are still unsatisfactory, justifying the search and intervention of the factors influencing the response to treatment.

METHODOLOGY

In order to determine the contribution of demographic, clinical and genetic variables on serum concentrations and response to methadone, we investigated patients on MMT, who were receiving methadone in supervised and unchanged doses at least during the previous two weeks. The age, gender, body mass index (BMI), duration of heroin abuse, addiction to other drugs, criminal background, current daily methadone doses, time spent in the TMM, comorbidity and concomitant medication were recorded. Blood samples were taken for the determination of serum levels of racemic methadone and its R and S-enantiomers, and for typing of candidate alleles of POR, CYP2B6, ABCB1, GRIN1, OPRM1, SLC6A3, DßH and ARRB2 genes, all associated with the metabolism, tissue distribution and mechanism of action of methadone. Methadone quantification was by HPLC-DAD, and the detection of genetic markers by Real Time PCR and VNTR methods.

RESULTS

A total of 80 subject volunteers were enrolled, with a mean age of 23.5 (5) years (86% male), all of them were addicts of multiple drugs, 60% with a criminal background, 5.1 (2.9) years taking heroin, and 5.3 (4) months on MMT, and taking a supervised dose of 41 (12) mg/day methadone. The (R), (S) and (R, S) methadone enantiomer trough plasma levels were, 84 (40), 84 (42), and 168 (77) ng/mL, respectively. All genotypes were in Hardy-Weinberg equilibrium. The two urine tests were negative for heroin in 61.3% (49/80) of the volunteers, the decline in cocaine/crack use was 83%, 30% of marijuana, and other psychoactives (inhalants, benzodiazepines, amphetamines) decreased to zero, while the consumption of snuff remained at 93.5% (75/80). Blood concentrations of racemic methadone and its enantiomers were significantly associated with the dose/day of the medication, but none of the other demographic, clinical or genetic variables impacted on serum levels of methadone. As for the results of the MMT, non-users and occasional users of heroin, as well as those who stopped taking other psychoactive drugs, and the ones who did not, were similar as regards the demographic, genetic and clinical variables. This included the blood metahdone concentrations, except for individuals who did not reduce their consumption of other psychoactives other than heroin, who had significantly (P=.03) higher blood levels of S-methadone, compared with those who did stop taking them.

CONCLUSIONS

There was a significant reduction in the consumption of heroin and other psychoactives, and social rehabilitation of patients. However, the extensive overlap between effective and ineffective doses of methadone suggests the presence of personal and social variables that transcend the simple pharmacological management. These probably need to be addressed more successfully from the psychosocial features, particularly as regards to identifying and overcoming relapse-trigger experiences, as well as certain features of the patient, such as their psychological distress level or their psychiatric disorders.

Meaning and methadone: patient perceptions of methadone dose and a model to promote adherence to maintenance treatment

OBJECTIVES

Methadone maintenance treatment (MMT) effectively reduces illicit opioid use and its negative consequences when patients participate in and adhere to treatment. Patients' participation and adherence may relate to their perceptions about methadone doses and dose adjustments and the meanings that patients associate with treatment. This study assessed patient perceptions about methadone dosing and the meanings associated with methadone treatment to better support patient adherence to and success in MMT.

METHODS

We conducted semistructured interviews with 19 patients in an urban MMT program. Interviews were transcribed verbatim and analyzed through an iterative process.

RESULTS

Participants' expressed perceptions about methadone doses related to ideas of "comfort" and "function," suggesting a model for determining dose appropriateness and "ideal" methadone dose based on various factors both intrinsic and extrinsic to MMT. Intrinsic factors included those exerting downward pressure on "ideal" methadone dose such as lack of control in treatment, disdain for getting "high," concerns about methadone dependence, and desire to avoid adverse effects; those exerting upward pressure such as concern about withdrawal; and those exerting mixed pressures such as methadone formulations. Extrinsic factors included those exerting downward pressure such as shame about and stigma around MMT; those exerting upward pressure such as medical conditions and medication interactions; and those exerting mixed pressures such as family and peer relationships.

CONCLUSIONS

Participants held perceptions about methadone dosing that included considerations beyond typical medical parameters used by physicians and other MMT providers to determine appropriate methadone doses. The model that emerged from our data could help inform MMT providers to support greater patient comfort with methadone doses and dose changes, as well as adherence to and success in MMT.

Controlled-release oxycodone and naloxone in the treatment of chronic low back pain: a placebo-controlled, randomized study

BACKGROUND

For Canadian regulatory purposes, an analgesic study was required to complement previously completed, pivotal studies on bowel effects and analgesia associated with controlled-release (CR) oxycodone⁄CR naloxone.

OBJECTIVES

To compare the analgesic efficacy and safety of CR oxycodone⁄CR naloxone versus placebo in patients with chronic low back pain.

METHODS

Patients requiring opioid therapy underwent a two- to seven-day opioid washout before being randomly assigned to receive either 10 mg⁄5 mg CR oxycodone⁄CR naloxone or placebo every 12 h, titrated weekly according to efficacy and tolerability to 20 mg⁄10 mg, 30 mg⁄15 mg or 40 mg⁄20 mg every 12 h. After four weeks, patients crossed over to the alternative treatment for an additional four weeks. Acetaminophen⁄codeine (300 mg⁄30 mg every 4 h to 6 h as needed) was provided as rescue medication.

RESULTS

Of the 83 randomized patients, 54 (65%) comprised the per-protocol population. According to per-protocol analysis, CR oxycodone⁄CR naloxone resulted in significantly lower mean (± SD)pain scores measured on a visual analogue scale (48.6 ± 23.1 mm versus 55.9 ± 25.4 mm; P=0.0296) and five-point ordinal pain intensity scores (2.1 ± 0.8 versus 2.4 ± 0.9; P=0.0415) compared with placebo. After the double-blinded phase, patients and investigators both preferred CR oxycodone⁄CR naloxone over placebo. These outcomes continued in the 79% of patients who chose to continue receiving CR oxycodone⁄CR naloxone in a six-month, open-label evaluation.

CONCLUSIONS

In patients complying with treatment as per protocol, CR oxycodone⁄CR naloxone was effective for the management of chronic low back pain of moderate or severe intensity.

Satisfaction with methadone as a medication: psychometric properties of the Spanish version of the treatment satisfaction questionnaire for medication

There is a manifest lack of psychometrically sound instruments designed for specific and multidimensional assessment of satisfaction with methadone as a medication within the context of methadone maintenance treatment. Therefore, it may be worthwhile to assess the pertinence and utility of using a generic and multidimensional medication satisfaction instrument that has not been specifically developed for use in methadone maintenance treatment.The aim of this study was thus to explore the psychometric properties of the Spanish version of the Treatment Satisfaction Questionnaire for Medication (TSQM version 1.4 [Health Qual Life Outcomes. 2004;2:12]) in a sample of methadone-maintained heroin-dependent patients.Two hundred three methadone-maintained patients filled out the TSQM and other several measures related to the construct of patient satisfaction (eg, Verona Service Satisfaction Scale for methadone treatment). Dimensionality of the TSQM was assessed by means of a confirmatory factor analysis. Internal consistency was examined using the ordinal coefficient α. Spearman correlations were used to explore the relationship between the TSQM and the measures conceptually related to patient satisfaction.Regarding the dimensionality of the TSQM, its original factor structure adequately fitted the data (Satorra-Bentler χ58, 72.14 [P = 0.100]; root-mean-square error of approximation, 0.045; comparative fit index, 0.978). All but 1 of the 4 TSQM subscales showed acceptable to good internal consistency values (0.78-0.89). The dimensions of the TSQM were differentially and congruently correlated with related measures.The results strongly suggest the TSQM value as a brief, generic, and psychometrically sound instrument to assess satisfaction with methadone as a medication in a multidimensional manner. Notwithstanding, more research is needed not only to assess the generalizability of these findings but also to provide pieces of evidence for other psychometric properties, especially the TSQM predictive validity.

Non-medical use of opioids among HIV-infected opioid dependent individuals on opioid maintenance treatment: the need for a more comprehensive approach

BACKGROUND

Opioid maintenance treatment (OMT) has a positive impact on substance use and health outcomes among HIV-infected opioid dependent patients. The present study investigates non-medical use of opioids by HIV-infected opioid-dependent individuals treated with buprenorphine or methadone.

METHODS

The MANIF 2000 study is a longitudinal study that enrolled a cohort of 476 HIV-infected opioid-dependent individuals. Data were collected in outpatient hospital services delivering HIV care in France. The sample comprised all patients receiving OMT (either methadone or buprenorphine) who attended at least one follow-up visit with data on adherence to OMT (N = 235 patients, 1056 visits). Non-medical use of opioids during OMT was defined as having reported use of opioids in a non-medical context, and/or the misuse of the prescribed oral OMT by an inappropriate route of administration (injection or sniffing). After adjusting for the non-random assignment of OMT type, a model based on GEE was then used to identify predictors of non-medical use of opioids.

RESULTS

Among the 235 patients, 144 (61.3%) and 91 (38.9%) patients were receiving buprenorphine and methadone, respectively, at baseline. Non-medical use of opioids was found in 41.6% of visits for 83% of individual patients. In the multivariate analysis, predictors of non-medical use of opioids were: cocaine, daily cannabis, and benzodiazepine use, experience of opioid withdrawal symptoms, and less time since OMT initiation.

CONCLUSIONS

Non-medical use of opioids was found to be comparable in OMT patients receiving methadone or buprenorphine. The presence of opioid withdrawal symptoms was a determinant of non-medical use of opioids and may serve as a clinical indicator of inadequate dosage, medication, or type of follow-up. Sustainability and continuity of care with adequate monitoring of withdrawal symptoms and polydrug use may contribute to reduced harms from ongoing non-medical use of opioids.

Elevated pain sensitivity in chronic pain patients at risk for opioid misuse

This study employed quantitative sensory testing (QST) to evaluate pain responses in chronic spinal pain patients at low risk and high risk for opioid misuse, with risk classification based on scores on the Screener and Opioid Assessment for Patients with Pain-Revised (SOAPP-R). Patients were further subgrouped according to current use of prescription opioids. Of the 276 chronic pain patients tested, approximately 65% were taking opioids; a median split was used to further categorize these patients as being on lower or higher doses of opioids. The high-risk group (n = 161) reported higher levels of clinical pain, had lower pressure and thermal pain thresholds at multiple body sites, had lower heat pain tolerance, and rated repetitive mechanical stimuli as more painful relative to the low-risk group (n = 115; P's < .01). In contrast, QST measures did not differ across opioid groups. Multiple linear regression analysis suggested that indices of pain-related distress (ie, anxiety and catastrophizing about pain) were also predictive of hyperalgesia, particularly in patients taking opioids. Collectively, regardless of opioid status, the high-risk group was hyperalgesic relative to the low-risk group; future opioid treatment studies may benefit from the classification of opioid risk, and the examination of pain sensitivity and other factors that differentiate high- and low-risk groups.

PERSPECTIVE

This study demonstrates that chronic spinal pain patients at high risk for misuse of prescription opioids are more pain-sensitive than low-risk patients, whether or not they are currently taking opioids. Indices of pain-related distress were important predictors of pain sensitivity, particularly among those patients taking opioids for pain.