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Background: The incidence of opioid-related fatality has reached unparalleled levels across North America. Patients with comorbid hepatitis C virus (HCV) remain the most vulnerable and difficult to treat. Considering the unique challenges associated with this population, we aimed to re-examine the impact of HCV on response to medication assistant treatment for opioid use disorder and establish sex-specific risk factors affecting care. Methods: This study employs a multi-center prospective cohort design, with 1-year follow-up. Patients aged ≥18, receiving methadone for opioid use disorder were recruited from a network of outpatient opioid addiction treatment centers across Southern Ontario, Canada. Patients with ≥50% positive opioid urine screens over 1 year of follow-up were classified as poor responders. The prognostic impact of HCV on response was established using a propensity score matched analysis. Sex-specific regression models were constructed to evaluate risk factors for treatment response. Results: Among participants eligible for inclusion (n = 1234), HCV was prevalent in 25% (n = 307). HCV patients exhibited significantly higher rates of high-risk opioid consumption patterns 35.29% (standard deviation 0.478). Sex-specific examination revealed females with HCV incur a 2 times increased risk for high-risk opioid consumption behaviors (female odds ratio: 1.95, 95% confidence interval 1.23, 3.10; P = 0.01). Conclusions: Findings from this study establish the link between HCV and poor treatment response, with differentially higher risk among female patients. In light of the high potential for overdose among this population, concerted efforts are required for distinguishing the source for sex-based disparities, in addition to establishing trauma and gender informed treatment protocols. [ABSTRACT FROM AUTHOR]

Background: Given the complex nature of opioid addiction treatment and the rising number of available opioid substitution and antagonist therapies (OSAT), there is no 'gold standard' measure of treatment effectiveness, and each successive trial measures a different set of outcomes which reflect success in arbitrary or opportune terms. We sought to describe the variation in current outcomes employed across clinical trials for opioid addiction, as well as determine whether a discrepancy exists between the treatment targets that patients consider important and how treatment effectiveness is measured in the literature.Methods: We searched nine commonly used databases (e.g., EMBASE, MEDLINE) from inception to August 1, 2015. Outcomes used across trials were extracted and categorized according to previously established domains. To evaluate patient-reported goals of treatment, semi-structured interviews were conducted with 18 adults undergoing methadone treatment.Results: We identified 60 trials eligible for inclusion. Once outcomes were categorized into eight broad domains (e.g., abstinence/substance abuse), we identified 21 specific outcomes with furthermore 53 subdomains and 118 measurements. Continued opioid use and treatment retention were the most commonly reported measures (46%, n = 28). The majority of patients agreed that abstinence from opioids was a primary goal in their treatment, although they also stressed goals under-reported in clinical trials.Conclusions: There is inconsistency in the measures used to evaluate the effectiveness of OSATs. Individual and population level decision making is being guided by a standard of effect considered useful to researchers yet in direct conflict with what patients deem important.Trial Registration: PROSPERO, CRD42013006507. [ABSTRACT FROM AUTHOR]

Objective: There is a significant interindividual variability in treatment outcomes in methadone maintenance treatment (MMT) for opioid use disorder (OUD). This prospective cohort study examines the impact of comorbid psychiatric disorders on continued illicit opioid use in patients receiving MMT for OUD. Methods: Data were collected from 935 patients receiving MMT in outpatient clinics between June 2011 and June 2015. Using linear regression analysis, we evaluated the impact of having a comorbid psychiatric disorder on continued illicit opioid use during MMT, adjusting for important confounders. The main outcome measure was percentage of opioid-positive urine screens for 6 months. We conducted a subgroup analysis to determine the influence of specific comorbid psychiatric disorders, including substance use disorders, on continued illicit opioid use. Results: Approximately 80% of participants had at least one comorbid psychiatric disorder in addition to OUD, and 42% of participants had a comorbid substance use disorder. There was no significant association between having a psychiatric comorbidity and continuing opioid use (P=0.248). Results from subgroup analysis, however, suggest that comorbid tranquilizer (ß=20.781, P,0.001) and cocaine (ß=6.344, P=0.031) use disorders are associated with increased rates of continuing opioid use. Conclusion: Results from our study may serve to guide future MMT guidelines. Specifically, we find that cocaine or tranquilizer use disorder, comorbid with OUD, places patients at high risk for poor MMT outcomes. Treatment centers may choose to gear more intensive therapy toward such populations. [ABSTRACT FROM AUTHOR]

Background: Despite the growing numbers of men and women with opioid use disorder in Canada, sex-specific issues in treatment have not been re-examined in the current population of patients with opioid addiction. We aimed to evaluate sex differences in substance use, health, and social functioning among men and women currently receiving methadone treatment for opioid use disorder in Ontario, Canada. Methods: We recruited 503 participants with opioid dependence disorder receiving methadone maintenance treatment. We collected data on demographics, treatment characteristics, psychiatric history, addiction severity, and drug use patterns through urinalysis. We performed adjusted univariate analyses and logistic regression to identify distinct factors affecting men and women. Results: Among our sample of 54 % (n = 266) men and 46 % women (n = 226) with mean age 38.3 years, less than half of participants were employed (35.6 %) and married (31.8 %) and had completed a high school education (27.9 %). Compared to men, women had frequent physical and psychological health problems, family history of psychiatric illness, and childcare responsibilities and began using opioids through a physician prescription. Men had higher rates of employment, cigarette smoking, and cannabis use compared to women. Conclusions: Our results have revealed different patterns of substance use, health, and social functioning among men and women currently receiving methadone treatment for opioid addiction in Ontario, Canada. This information can be used to develop an integrative treatment regimen that caters to the individual needs of men and women, as well as to inform methadone treatment protocols to include specialized services (including vocational counseling, childcare and parenting assistance, medical assistance, relationship or domestic violence counseling, etc.) and increase their availability and accessibility on a larger scale. [ABSTRACT FROM AUTHOR]

Background: Eligibility criteria that result in the exclusion of a substantial number of patients from randomized trials jeopardize the generalizability of treatment effect to much of the clinical population. This is important when evaluating opioid substitution and antagonist therapies (OSATs), especially given the challenges associated with treating the opioid-dependent population. We aimed to identify OSAT trials' eligibility criteria, quantify the percentage of the clinical population excluded by these criteria, and determine how OSAT guidelines incorporate evidence from these trials.Methods: We performed a systematic review to identify the eligibility criteria used across trials. We searched Medline, EMBASE, PsycINFO, Web of Science, Cochrane Library, Cochrane Clinical Trials Registry (CTR), World Health Organization International CTR Platform Search Portal, and the National Institutes of Health CTR databases from inception to January 1, 2014. To quantify the effect of trials' eligibility criteria on generalizability, we applied these criteria to data from an observational study of opioid-dependent patients (n = 394). We then accessed the Canadian, American, British, and World Health Organization (WHO) OSAT guidelines to evaluate how evidence is used in the recommendations.Results: Among the 60 trials identified the majority (≥50 % of trials) exclude patients with psychiatric (60 %) and physical comorbidity (51.7 %). Additionally, we found 19 trials exclude patients with current alcohol/substance-use problems (31.7 %), and 29 (48.3 %) exclude patients taking psychotropic medications. These criteria were restrictive and in some cases rendered 70 % of the observational sample ineligible. North American OSAT guidelines made strong recommendations supported by evidence with poor generalizability. National Institute of Health and Care Excellence (NICE) and WHO guidelines for opioid misuse provide a critical assessment of the literature used to inform their recommendations.Conclusions: Trials assessing OSATs often exclude patients with concurrent disorders. If the excluded patients respond differently to treatment, results from these trials are likely to overestimate the true effectiveness of OSATs. North American guidelines should consider these limitations when drafting clinical recommendations. [ABSTRACT FROM AUTHOR]

Background: The heritability of opioid use disorder has been widely investigated; however, the influence of specific genes on methadone treatment outcomes is not well understood. The association between response to methadone treatment and genes that are involved in substance use behaviors and reward mechanisms is poorly understood, despite evidence suggesting their contribution to opioid use disorder. The aim of this study was to investigate the effect of brain-derived neurotrophic factor (BDNF) and dopamine receptor D2 (DRD2) polymorphisms on continued opioid use among patients on methadone treatment for opioid use disorder. Methods: BDNF 196G>A (rs6265) and DRD2-241A>G (rs1799978) genetic variants were examined in patients with opioid use disorder who were recruited from methadone treatment clinics across Southern Ontario, Canada. We collected demographic information, substance use history, blood for genetic analysis, and urine to measure opioid use. We used regression analysis to examine the association between continued opioid use and genetic variants, adjusting for age, sex, ethnicity, methadone dose, duration in treatment, and number of urine screens. Results: Among 240 patients treated with methadone for opioid use disorder, 36.3 percent (n = 87) and 11.3 percent (n = 27) had at least one risk allele for rs6265 and rs1799978, respectively. These genetic variants were not significantly associated with continued opioid use while on methadone maintenance treatment [rs6265: odds ratio (OR) = 1.37, 95 % confidence interval (CI) = 0.792, 2.371, p = 0.264; rs1799978: OR 1.27, 95 % CI 0.511, 3.182, p = 0.603]. Conclusions: Despite an association of BDNF rs6265 and DRD2 rs1799978 with addictive behaviors, these variants were not associated with continued illicit opioid use in patients treated with methadone. Problematic use of opioids throughout treatment with methadone may be attributed to nongenetic factors or a polygenic effect requiring further exploration. Additional research should focus on investigating these findings in larger samples and different populations. [ABSTRACT FROM AUTHOR]

Background: Opioid use disorder is a serious international concern with limited treatment success. Men and women differ in their susceptibility to opioid use disorder and response to methadone treatment and can therefore benefit from sex-specific treatment. We performed a systematic review of the literature on outcomes of methadone maintenance treatment for opioid use disorder in men and women related to drug use, health status and social functioning. Methods: We searched PubMed, Embase, PsycINFO and CINAHL for observational or randomized controlled studies involving adults 18 years of age or older undergoing methadone treatment for opioid use disorder. Studies were included if they investigated sex differences in methadone treatment outcomes. Two authors independently reviewed and extracted data. Meta-analyses were performed when possible; risk of bias and quality of evidence were also assessed. Results: Twenty studies with 9732 participants were included, of which 18 were observational and 2 were randomized controlled trials. Men and women differed significantly in alcohol use (odds ratio [OR] 0.52, 95% confidence interval [CI] 0.31 to 0.86), amphetamine use (OR 1.47, 95% CI 1.12 to 1.94), legal involvement (OR 0.63, 95% CI 0.47 to 0.84) and employment during treatment (OR 0.39, 95% CI 0.21 to 0.73). Opioid use patterns were similar among men and women. Risk of bias was moderate, and quality of evidence was generally low. Interpretation: Sex differences were evident in polysubstance use, legal involvement and employment status among men and women receiving methadone treatment for opioid use disorders. Although the quality of evidence was low, our review highlights the need for improved implementation of sex-specific treatment strategies. [ABSTRACT FROM AUTHOR]

Background: Chronic pain is the most commonly reported comorbidity among patients with opioid addiction receiving methadone maintenance treatment (MMT), with an estimated prevalence ranging between 30% and 55%. Evidence suggests that patients with comorbid pain are at high risk for poor treatment response, including continued illicit substance use. Due to the important relationship between the presence of pain and illicit substance abuse within the MMT setting, it is imperative that we target our efforts toward understanding the characteristics of this patient population. Methods: The primary objective of this study was to explore the clinical and inflammatory profile of MMT patients reporting comorbid pain. This multicenter study enrolled patients (n=235) on MMT for the treatment of opioid dependence. Clinical history and blood and urine data were collected. Blood samples were obtained for estimating the serum levels of inflammatory markers (tumor necrosis factor [TNF]-α, interleukin-1 receptor antagonist [IL-1ra], IL-6, IL-8, IL-10, interferon [IFN]-γ and chemokine (C–C motif) ligand 2 [CCL2]). The study objectives were addressed using a descriptive statistical summary and a multivariable logistic regression model constructed in STATA version 12. Results: Among the participants eligible for inclusion (n=235), serum IFN-γ level and substance abuse behavior proved to be important delineating characteristics for the detection of comorbid pain. Analysis of inflammatory profile showed IFN-γ to be significantly elevated among patients reporting comorbid pain (odds ratio [OR]: 2.02; 95% confidence interval [CI]: 1.17, 3.50; P=0.01). Patients reporting comorbid pain were also found to have an increase in positive opioid urine screens (OR: 1.02; 95% CI: 1.00, 1.03; P=0.01), indicating an increase in illicit opioid consumption. Conclusion: MMT patients with comorbid pain were shown to have elevated IFN-γ and higher rates of continued opioid abuse. The ability to objectively distinguish between patients with comorbid pain may help to both improve the prediction of poor responders to MMT as well as identify treatment approaches such as anti-inflammatory medications as safe alternatives for MMT patients with comorbid pain. [ABSTRACT FROM AUTHOR]

Sex hormones may have a role in the pathophysiology of substance use disorders, as demonstrated by the association between testosterone and addictive behaviour in opioid dependence. Although opioid use has been found to suppress testosterone levels in men and women, the extent of this effect and how it relates to methadone treatment for opioid dependence is unclear. The present multi-centre cross-sectional study consecutively recruited 231 patients with opioid dependence from methadone clinics across Ontario, Canada between June and December of 2011. We obtained demographic details, substance use, psychiatric history, and blood and urine samples from enrolled subjects. The control group included 783 non-opioid using adults recruited from a primary care setting in Ontario, Canada. Average testosterone level in men receiving methadone treatment was significantly lower than controls. No effect of opioids including methadone on testosterone level in women was found and testosterone did not fluctuate significantly between menstrual cycle phases. In methadone patients, testosterone level was significantly associated with methadone dose in men only. We recommend that testosterone levels be checked in men prior and during methadone and other opioid therapy, in order to detect and treat testosterone deficiency associated with opioids and lead to successful methadone treatment outcomes. [ABSTRACT FROM AUTHOR]

Introduction: Treatment of opioid addiction with methadone is effective; however, it is known to produce interindividual variability. This may be influenced in part by genetic variants, which can increase the initial risk of developing opioid addiction as well as explain differences in response to treatment. This pilot study aimed to assess the feasibility of conducting a full-scale genetic analysis to identify genes that predict methadone treatment outcomes in this population. Methods: This was a cross-sectional observational study of patients admitted to a methadone maintenance treatment program for opioid addiction. We obtained demographic and clinical characteristics in addition to blood and urine samples, for the assessment of treatment outcomes. Results: The recruitment process yielded 252 patients, representing a 20% recruitment rate. We conducted genetic testing based on a 99.6% rate of provision of DNA samples. The average retention in treatment was 3.4 years, and >50% of the participants reported psychiatric and medical comorbidities. BDNF rs6265 and DRD2 rs1799978 were the common single nucleotide polymorphisms (SNPs) selected for the feasibility study. Discussion: This study met our predetermined feasibility criteria; recruitment, response rates, and genetic testing were feasible; treatment duration was sufficient for follow up; and the prevalence of comorbid conditions indicated the need for reliable psychiatric and chronic pain measures. The study strengths included effective collaboration with clinics and the generalizability of sample population. Key learning points show the need for assessment of treatment outcomes on multiple domains, implementation of follow up, and the development of standardized training for the study clinical staff. [ABSTRACT FROM AUTHOR]

Background: Genetic variability may influence methadone metabolism, dose requirements, and risk of relapse. Objectives: To determine whether the CYP2B6*6 or ABCB1 (rs1045642) polymorphisms are associated with variation in methadone response (plasma concentration, dose, or response to treatment). Methods: Two independent reviewers searched Medline, EMBASE, CINAHL, PsycINFO, and Web of Science databases. We included studies that reported methadone plasma concentration, methadone response, or methadone dose in relation to the CYP2B6*6 or ABCB1 polymorphisms. Results: We screened 182 articles and extracted 7 articles for inclusion in the meta-analysis. Considerable agreement was observed between the two independent raters on the title (kappa, 0.82), abstract (kappa, 0.43), and full text screening (kappa, 0.43). Trough (R) methadone plasma concentration was significantly higher in CYP2B6*6 homozygous carriers when compared to non-carriers (standardized mean difference [SMD] = 0.53, 95% confidence interval [CI], 0.05–1.00, p = 0.03) with minimal heterogeneity (I2 = 0%). Similarly, trough (S) methadone plasma concentration was higher in homozygous carriers of the *6 haplotype when compared to non-carriers, (SMD = 1.44, 95% CI 0.27–2.61, p = 0.02) however significant heterogeneity was observed (I2 = 69%). Carriers of the CYP2B6*6 haplotype were not found to be significantly different from non-carriers with respect to dose or response to treatment. We found no significant association between the ABCB1 polymorphism and the trough (R), (S) plasma concentrations, methadone dose, or methadone response. Conclusion: Although the number of studies included and sample size were modest, this is the first meta analysis to show participants homozygous for the CYP2B6*6 genotype have higher trough (R) and (S) methadone plasma concentrations, suggesting that methadone metabolism is significantly slower in *6 homozygous carriers. [ABSTRACT FROM AUTHOR]

Introduction: Despite the demonstrated benefit of methadone, the incidence opioid-related overdose, and its associated mortality continues to rise at an alarming rate. The impact of high prevalence comorbid features such as chronic liver disease (CLD) on methadone treatment response remain unclear.Aim: To determine whether CLD is associated with poor response to methadone treatment.Methods: Using a well-established multi-center cohort from the Genetics of Opioid Addiction Study (GENOA), we evaluated if presence of CLD among 1234 eligible patients with opioid use disorder receiving methadone treatment impacted health and behavioural responses to treatment. CLD was classified as any liver disorder/dysfunction present for a minimum period of six months. Serial urine toxicology assessments were used to determine treatment response. The effect of CLD was determined using a multi-variable logistic regression model.Results: CLD was present in 25 % (n = 314) of the population. On average, patients with CLD were found to be older (mean age 44 vs 36 years, p < 0.0001), unemployed (81.8 % vs 61 %, p < 0.0001), and receiving government disability benefits at significantly higher rates (21.9 % vs 11 %, p < 0.0001). Increased levels of physical craving, emotional stress, as well as health risk behaviors were noted in CLD patients. Findings from the multi-variable model demonstrate a 68 % increased risk for dangerous opioid consumption behaviors (Odds Ration [OR]: 1.68, 95 % Confidence Interval [CI] 1.22, 2.31, p = 0.001) among patients with CLD. Methadone dose (OR: 0.76, 95 % CI 0.70, 0.81, p < 0.0001) was shown to be protective with a significant risk reduction of 24 % per 20 mg increase in methadone. Duration in treatment was also found to be protective (OR: 0.99, 95 % CI 0.97, 0.99, p < 0.0001).Conclusion: CLD poses a distinct risk for patients with opioid addiction. Closer drug monitoring, and substance use contingency management should be considered to reduce mortality risk in these patients. [ABSTRACT FROM AUTHOR]

Background Whether used for pain management or recreation, opioids have a number of adverse effects including hormonal imbalances. These imbalances have been reported to primarily involve testosterone and affect both males and females to the point of interfering with successful treatment and recovery. We conducted a systematic review and meta-analysis to determine the extent that opioids affect testosterone levels in both men and women, which may be relevant to improved treatment outcomes for opioid dependence and for pain management. Methods We searched PubMed, EMBASE, PsycINFO, and CINAHL for relevant articles and included studies that examined testosterone levels in men and women while on opioids. Data collection was completed in duplicate. Results Seventeen studies with 2769 participants (800 opioid users and 1969 controls) fulfilled the review inclusion criteria; 10 studies were cross-sectional and seven were cohort studies. Results showed a significant difference in mean testosterone level in men with opioid use compared to controls (MD = −164.78; 95% CI: −245.47, −84.08; p < 0.0001). Methadone did not affect testosterone differently than other opioids. Testosterone levels in women were not affected by opioids. Generalizability of results was limited due to high heterogeneity among studies and overall low quality of evidence. Conclusions Our findings demonstrated that testosterone level is suppressed in men with regular opioid use regardless of opioid type. We found that opioids affect testosterone levels differently in men than women. This suggests that opioids, including methadone, may have different endocrine disruption mechanisms in men and women, which should be considered when treating opioid dependence. [ABSTRACT FROM AUTHOR]