Contributing Factors to Methadone-Related Deaths in Ontario

Opioid-related deaths in Northern Ontario in the early COVID-19 pandemic period

OBJECTIVES

In the first year of pandemic measures, opioid-related deaths across Ontario's (ON) 34 public health units (PHUs) increased by 60%. Death rates for all seven Northern ON PHUs were above the provincial average. This study describes and compares factors surrounding opioid-related deaths before and after pandemic measures were introduced, for Northern ON compared to the rest of ON.

METHODS

Aggregate data were provided for Northern ON and the rest of the province by the Office of the Chief Coroner/Ontario Forensic Pathology Services. Opioid-related deaths were cohorted by date of death for the year before and after pandemic measures were introduced on March 16, 2020. Chi-square tests were used to compare between cohorts and geographies to determine significant differences for each variable, and for dichotomized levels within variables. P-values < 0.05 were considered statistically significant a priori.

RESULTS

In Northern ON, the number of opioid-related deaths approximately doubled from the pre-pandemic cohort (n = 185) to the early pandemic cohort (n = 365). Compared to the rest of ON, higher proportions of deaths occurred in Northern ON among individuals who lived and died in private residences, among women (although the majority of decedents were male) and among individuals employed in mining, quarrying, and oil and gas industries. Compared to the pre-pandemic year, in Northern ON, higher proportions of opioid-related deaths involved fentanyl and stimulants as direct contributors, and the majority involved evidence of inhaled drugs.

CONCLUSION

Differences between the circumstances of death in Northern ON and in the rest of ON suggest opportunities to tailor interventions.

Prescribed and Diverted Methadone Toxicity in South Australia: An Update

ABSTRACT

Methadone is one of the most common medications currently prescribed for the treatment of opioid use disorders (OUDs). While methadone maintenance programs (MMPs) have been highly successful in the management and treatment of OUDs resulting in a reduced number of fatalities, the risk of overdose/toxicity remains. The current study was undertaken to analyze trends in overdoses attributed to prescribed and diverted methadone in South Australia (SA) between 2000 and 2019. Over the 20-year period, 344 methadone-related deaths occurred in SA with a significant increase in deaths over the study period ( P = 0.03). The mean age of decedents was 42.5 years with a male to female ratio of 1.8:1, with approximately 20% of decedents enrolled in a MMP at the time of death. Overall, only 5.2% of cases demonstrated methadone diversion, which was associated with methadone prescribed for chronic pain and was most likely to be diverted from a friend/housemate or a partner. However, the source of methadone in more than half of cases was unknown, so this is likely a significant underestimate of actual MMP methadone diversion and total methadone diversion.

Is high sensitive-troponin I a reliable biomarker for cardiac injury in methadone toxicity? A prospective cross-sectional study

Background

Methadone is a synthetic opioid mostly used for detoxification therapy, as its use increases; the possibility for methadone-induced cardiotoxicity may rise. The aim of this study was to determine the association of high-sensitivity troponin I levels as a predictor of cardiac injury in methadone toxicity.

Methods

Sixty methadone toxicity patients included in this prospective cross-sectional study from October 2018–November 2020. High-sensitivity troponin I level and electrocardiogram were assessed in patients at admission. All patients underwent echocardiography at admission and 30 days later and compared this finding between two groups based on high-sensitivity troponin I results.

Results

Mean age of the patients was 34.5 ± 11.1 years (males: 67%). Twenty (20%) patients had positive high sensitive-troponin results. Long QT interval and inverted T in precordial leads were mostly observed in individuals with positive high-sensitivity troponin I (75% vs. 35%, P = 0.013 and 83% vs. 16%, P < 0.001, respectively). Patients with elevated troponin had reduced left ventricular ejection fraction in comparison to normal group during admission (43.1 ± 15.4% vs. 55%, P < 0.001) and this left ventricular ejection fraction remained abnormal after 30 days (43.7 ± 21.6%). Patients in positive high-sensitivity troponin I group had higher regional wall motion abnormality frequency both at admission and 30 days later compared to the other group (0 day: 42% vs. 0, P < 0.001, 30th days: 25% vs. 4%, P = 0.020).

Conclusion

Patients with simultaneous methadone toxicity and positive high-sensitivity troponin I had worse cardiac outcomes and this biomarker could be probably used for better implementation of therapeutic interventions and prognosis.

The utility of lung weight to heart weight ratio as a means to identify suspected drug intoxication deaths in a medico-legal autopsy population

Fatal intoxications are common in a medico-legal autopsy setting and are associated with sparse findings during autopsy. It has been suggested that an increased lung weight may be associated with such fatalities. Previous literature is generally limited to a descriptive approach, including only opioid deaths, and lacking a definition of "heavy" lungs. Our aim was to create a model to identify cases with heavy lungs and to assess the predictive power of "heavy" lungs in identifying cases of different types of fatal intoxications during autopsy in an unselected medico-legal autopsy population. We identified all medico-legal autopsy cases ≥18 years in Sweden from 2000 through 2013. The lung weight to heart weight (LWHW) ratio was calculated. The positive predictive values (PPV) and negative predictive values (NPV) of both lung weight and LWHW ratio were calculated. Mean lung weight was higher in the intoxication group but the predictive power in the individual case was limited. Lung weight to heart weight ratio had better predictive power than lung weight alone, with a PPV of at most 0.15(0.14, 0.16 95% CI), while the NPV was 0.96 (0.95, 0.96 95% CI). The association between fatal intoxication and increased lung weight was positive, regardless of method and cutoffs used. While the PPV was poor, the NPV could reduce suspicion of fatal intoxication in the absence of other information. LHWH ratio is only a probability factor for fatal intoxication; accurate cause of death determination-as always-requires consideration of circumstances, autopsy, and toxicologic findings.

The Role of Risk or Contributory Death Factors in Methadone-Related Fatalities: A Review and Pooled Analysis

Methadone-related deaths are characterized by a wide range of post-mortem blood concentrations, due to the high pharmacokinetic/dynamic inter-individual variability, the potential subjective tolerance state and to other risk factors or comorbidities, which might enhance methadone acute toxicity. In the present study, the association among pre-existing and external conditions and diseases and the resultant methadone death capacity have been investigated. Beside a systematic literature review, a retrospective case-control study was done, dividing cases in which methadone was the only cause of death (controls), and those with associated clinical-circumstantial (naive/non-tolerant state), pathological (pulmonary or cardiovascular diseases) or toxicological (other drugs detected) conditions. Methadone concentrations were compared between the two groups and the association with conditions/diseases was assessed by multiple linear and binomial logistic regressions. Literature cases were 139, in house 35, consisting of 22 controls and 152 cases with associated conditions/diseases. Mean methadone concentrations were 2122 ng/mL and 715 ng/mL in controls and cases respectively, with a statistically significant difference (p < 0.05). Lower methadone concentrations (by 24, 19 and 33% respectively) were detected in association with naive/non-tolerant state, pulmonary diseases and presence of other drugs, and low levels of methadone (<600 ng/mL) might lead to death in the presence of the above conditions/diseases.

Changes in opioid-related deaths following increased access to opioid substitution treatment

BACKGROUND

Opioid-related mortality is high and increasing in the Western world, and interventions aimed at reducing opioid-related deaths represent an important area of study. In Skåne County, Sweden, a patient choice reform resulted in increased access to opioid substitution treatment (OST). In addition, a gradual shift towards less restrictive terms for exclusion from OST has been implemented. The aim of this study was to assess the impact of these policy changes on opioid-related deaths.

METHODS

Detailed data on opioid-related deaths in Skåne during the 2 years prior to and following the policy change were obtained from forensic records and from health care services. Data on overdose deaths for Skåne and the rest of Sweden were obtained using publicly available national register data. Time periods were used as the predictor for opioid-related deaths in the forensic data. The national level data were used in a natural experiment design in which rates of overdose deaths were compared between Skåne and the rest of Sweden before and after the intervention.

RESULTS

There was no significant difference in the number of deaths in Skåne between the data collection periods (RR: 1.18 95% CI:0.89-1.57, p= 0.251). The proportion of deaths among patients enrolled in OST increased between the two periods (2.61, 1.12-6.10, p= 0.026). There was no change in deaths related to methadone or buprenorphine in relation to deaths due to the other opioids included in the study (0.92, 0.51-1.63, p= 0.764). An analysis of national mortality data showed an annual relative decrease in unintentional drug deaths in Skåne compared to the rest of Sweden following the onset of the reform (0.90, 0.84-0,97, p= 0.004).

CONCLUSIONS

Opioid-related deaths, as assessed using forensic data, has not changed significantly in Skåne following a change to lower-threshold OST. By contrast, national level data indicate that the policy change has been associated with decreased overdose deaths. The discrepancy between these results highlights the need for more research to elucidate this issue. The result that more patients die during ongoing OST following an increase in access to treatment underlines the need for further preventive interventions within the OST treatment setting.

Against Repurposing Methadone for Glioblastoma Therapy

Methadone, which is used as maintenance medication for outpatient treatment of opioid dependence or as an analgesic drug, has been suggested by preclinical in vitro and mouse studies to induce cell death and sensitivity to chemo- or radiotherapy in leukemia, glioblastoma, and carcinoma cells. These data together with episodical public reports on long-term surviving cancer patients who use methadone led to a hype of methadone as an anti-cancer drug in social and public media. However, clinical evidence for a tumoricidal effect of methadone is missing and prospective clinical trials, except in colorectal cancer, are not envisaged because of the limited preclinical data available. The present article reviews the pharmacokinetics, potential molecular targets, as well as the evidence for a tumoricidal effect of methadone in view of the therapeutically achievable doses in the brain. Moreover, it provides original in vitro data showing that methadone at clinically relevant concentrations fails to impair clonogenicity or radioresistance of glioblastoma cells.

Alcohol and other drugs in suicide in Canada: opportunities to support prevention through enhanced monitoring

The use of alcohol and other drugs has been identified as a significant factor related to suicide through multiple pathways. This paper highlights current understanding of their contributions to suicide in Canada and identifies opportunities for enhancing monitoring and prevention initiatives. Publications from 1998 to 2018 about suicide in Canada and that referred to alcohol or other drugs were identified using PubMed and Google Scholar. A second literature search restricted to articles including results of toxicology testing was conducted by a librarian. We summarised the literature identified on ecological analyses, attributable fractions and deaths, and research including the results of toxicological analyses. Our literature search yielded 5230 publications, and 164 documents were identified for full-text screening. We summarised the findings from 30 articles. Ecological analyses support the association between alcohol sales, annual per capita alcohol consumption and suicide rates. Based on published estimates, approximately a quarter of suicide deaths in Canada are alcohol-attributable, while the estimated attributable fraction for illegal drugs is more variable. Finally, there is a dearth of literature examining the role of acute alcohol and/or drug consumption prior to suicide based on toxicological findings. The proportion of suicide decedents with drugs or alcohol present at the time of death varies widely. While there is evidence on the role of alcohol and drugs in suicide deaths, there is not a large body of research about the acute use of these substances at the time of death among suicide decedents in Canada. Our understanding of the role of alcohol and other drugs in suicide deaths could be enhanced through systematic documentation, which in turn could provide much needed guidance for clinical practice, prevention strategies and policy initiatives.

Correlations between population-levels of prescription opioid dispensing and related deaths in Ontario (Canada), 2005-2016

Canada is experiencing an ongoing opioid-related public health crisis, including persistently rising opioid (e.g., poisoning) mortality. Previous research has documented marked correlations between population-levels of opioid dispensing and deaths. We examined possible correlations between annual population-level dispensing of specific opioid formulations and related poisoning deaths in Ontario (Canada), for the period 2005-2016. Annual coroner statistics-based numbers of poisoning deaths associated with six main opioid formulations (codeine, fentanyl, hydromorphone, methadone, morphine, and oxycodone) for Ontario were converted into annual death rates (per 100,000 population). Annual dispensing data for the opioid formulations under study were based on commercial retail-sales data from a representative, stratified sample of community pharmacies (IMSQuintiles/IQVIA CompuScript), converted into Defined Daily Doses (DDD/1,000 population/day). Possible relationships between the annual death and dispensing rates were assessed by Pearson's correlation coefficient analyses. Death rates increased for almost all, while dispensing rates increased for half of the opioid categories. A significant positive correlation between death and dispensing rates was found for hydromorphone (r = 0.97, 95% CI: 0.88-0.99) and oxycodone (r = 0.90, 95% CI: 0.68-0.97) formulations; a significant negative correlation was found for codeine (r = -0.78, 95% CI: -0.93 to -0.37). No significant correlations were detected for fentanyl, methadone, and morphine related deaths. Strong correlations between levels of dispensing and deaths for select opioid formulations were found. For select others, extrinsic factors - e.g., increasing involvement of non-medical opioid products (e.g., fentanyl) in overdose deaths - likely confounded underlying correlation effects. Opioid dispensing levels continue to influence population-level mortality levels, and need to be addressed by prevention strategies.

Correlates of cocaine use during methadone treatment: implications for screening and clinical management (ANRS Methaville study)

Background

Cocaine use is frequent in patients receiving methadone maintenance treatment (MMT) and can jeopardize their treatment response. Identifying clinical predictors of cocaine use during methadone treatment can potentially improve clinical management. We used longitudinal data from the ANRS Methaville trial both to describe self-reported occasional and regular cocaine use during MMT and to identify clinical predictors.

Methods

We selected 183 patients who had data on cocaine (or crack) use at months 0 (M0), M6, and/or M12, accounting for 483 visits. The outcome was “cocaine use” in three categories: “no,” “occasional,” and “regular” use. To identify factors associated with the outcome over time, we performed a mixed multinomial logistic regression.

Results

Time on methadone was significantly associated with a decrease in occasional but not in regular cocaine use from 14.7 % at M0 to 7.1 % at M12, and from 10.7 % at baseline to 6.5 % at M12, respectively. After multiple adjustments, opiate injection, individuals screening positive for attention deficit hyperactivity disorder (ADHD) symptoms, and those presenting depressive symptoms were more likely to regularly use cocaine.

Conclusions

Although time on MMT had a positive impact on occasional cocaine use, it had no impact on regular cocaine use. Moreover, regular cocaine users were more likely to report opiate injection and to present ADHD and depressive symptoms. Early screening of these disorders and prompt tailored pharmacological and behavioral interventions can potentially reduce cocaine use and improve response to MMT.

Trial registration

The trial is registered with the French Agency of Pharmaceutical Products (AFSSAPS) under the number 2008-A0277-48, the European Union Drug Regulating Authorities Clinical Trials, number Eudract 2008-001338-28, the ClinicalTrials.gov Identifier: NCT00657397, and the International Standard Randomised Controlled Trial Number Register ISRCTN31125511.

Therapeutic and recreational methadone cardiotoxicity

Several classes of drugs have been associated with an increased risk of cardiovascular disease and occurrence of arrhythmias potentially involved in sudden deaths in chronic users even at therapeutic doses. The study presented herein focuses on pathological changes involving the heart possibly due to methadone use. 60 cases were included in the study in total and were divided into three groups (therapeutic methadone users: 20 cases, recreational methadone users: 20 cases, and sudden death group in subjects who had never taken methadone: 20 cases). Autopsies, histology, biochemistry and toxicology were performed in all cases. Macroscopic and microscopic investigation results in therapeutic methadone users were similar to those observed in sudden, unexpected deaths in non-methadone users. In recreational methadone consumers, macroscopic and microscopic examination of the heart failed to provide results consistent with acute or chronic myocardial or coronary damage, thereby corroborating the hypothesis of death most likely following respiratory depression.

Drugs of abuse and addiction: A slippery slope toward liver injury

Substances of abuse induce alteration in neurobehavioral symptoms, which can lead to simultaneous exacerbation of liver injury. The biochemical changes of liver are significantly observed in the abused group of people using illicit drugs or drugs that are abused. A huge amount of work has been carried out by scientists for validation experiments using animal models to assess hepatotoxicity in cases of drugs of abuse. The risk of hepatotoxicity from these psychostimulants has been determined by different research groups. Hepatotoxicity of these drugs has been recently highlighted and isolated case reports always have been documented in relation to misuse of the drugs. These drugs induce liver toxicity on acute or chronic dose dependent process, which ultimately lead to liver damage, acute fatty infiltration, cholestatic jaundice, liver granulomas, hepatitis, liver cirrhosis etc. Considering the importance of drug-induced hepatotoxicity as a major cause of liver damage, this review emphasizes on various drugs of abuse and addiction which induce hepatotoxicity along with their mechanism of liver damage in clinical aspect as well as in vitro and in vivo approach. However, the mechanisms of drug-induced hepatotoxicity is dependent on reactive metabolite formation via metabolism, modification of covalent bonding between cellular components with drug and its metabolites, reactive oxygen species generation inside and outside of hepatocytes, activation of signal transduction pathways that alter cell death or survival mechanism, and cellular mitochondrial damage, which leads to alteration in ATP generation have been notified here. Moreover, how the cytokines are modulated by these drugs has been mentioned here.

Characteristics of methadone-related fatalities in Norway

There are currently over 7000 patients enrolled in opioid maintenance treatment (OMT) programs in Norway. A rise in methadone-related deaths proportional to increasing methadone sales over the period 2000-2006 has been observed, but the causative factors for these fatalities have been elusive. In the present study, individual characteristics, methadone concentrations and additional toxicological findings were analyzed. Methadone intoxication deaths (n = 264) were divided into 3 groups according to toxicological findings in whole blood: group 1 - methadone detected alone, or together with one additional drug at low or therapeutic levels, or a low concentration of ethanol (<1 g/L) (n = 21); group 2 - multiple additional drugs/substances detected below lethal levels (n = 175); group 3 - one or more additional drugs/substances detected at lethal levels, or ethanol >3 g/L (n = 55). Methadone blood concentrations in decedents who had been enrolled in OMT were higher than for decedents not in treatment, in all groups. Blood methadone concentrations around 1 mg/L were present in fatal multi-drug intoxications in OMT patients. Results suggest that some patients may be at risk of dying when combining therapeutic concentrations of methadone with other psychoactive substances. Somatic disease was a common finding among deceased OMT patients. Concentrations in methadone users not enrolled in OMT were predominantly between 0.3 and 0.4 mg/L and were not related to the presence of other drugs. However, methadone concentrations below 0.1 mg/L may be associated with intoxication following methadone use, both alone and in combination with other drugs. Younger male users (mean age 34 years) seemed to have a higher susceptibility to methadone intoxication.

Drug-related deaths between 2002 and 2013 with accent to methadone and benzodiazepines

AIM

The aim of the study is to assess the trends of overdose and drug related fatalities in the Republic of Macedonia during the 11 years.

MATERIAL AND METHODS

Cross-sectional retrospective survey and reviewed of postmortem toxicological analyses which examined fatal poisonings with illegal drugs in years 2002-2013. Information about gender, age, drug consumption, reported years were analyzed. Narcotics were confirmed with toxicological semi quantitative fluorescence polarization immunoassay (FPIA) in urine (range 250-4000 ng/ml).

RESULTS

Total of 165 deaths were observed. Out of them 145 (87.9%) were male. There is statistical significant differences between male and female DRD due to age (Mann-Whitney U Test = 925, Z = -2626, p = 0.0087). For p < 0.05 there is significant differences between genders due to cause of overdose (Pearson Chi-square = 9743, df = 4, p = 0.0449). DRD among male were mainly because of overdose due to heroin in 80 (51.17%) cases followed by DRD due to combination of methadone and BZD in 25 (11.72%) cases. Out of all DRD cases 50 (30.3%) are related to polydrug use. For p < 0.01 there is a significant differences between analyzed age groups due to cause of overdose (Pearson Chi-square = 33,886, df = 12, p = 0.0007).

CONCLUSIONS

Death cause analysis reveals the difficulties in determining the role of substitution drugs, as many other factors may be involved. The findings also highlight the importance of further enhancing treatment interventions for benzodiazepine misuse among patients on methadone substitution treatment.

Prognostic factors in acute methadone toxicity: a 5-year study

Background. Delayed or recurrent profound respiratory depression, ventricular dysrhythmias, acute lung injury, and death are the major complications of MTD overdose. We aimed to clarify the prognostic factors in MTD toxicity. Materials and Methods. Retrospectively, medical files of all patients poisoned by MTD and older than 12 years of age who had presented to Loghman Hakim Poison Center between 2007 and 2012 were evaluated. The data was compared between survivors and nonsurvivors. Results. Twenty-eight out of 322 patients died (mortality rate = 8.7%). MTD-related death was higher in patients with acute on chronic toxicity who were on daily dose of MTD and had ingested higher doses (in comparison to those with acute toxicity due to first-time exposure; 13% versus 6%). Renal failure was the most common medical complication related to deaths due to MTD toxicity. Conclusions. Based on previous researches, the most common cause of MTD overdose-related deaths is respiratory impairment; however, in our study, acute renal failure with or without rhabdomyolysis was the main delayed cause of deaths in MTD-poisoned patients. Antidotal therapy, early recognition, and treatment of hemodynamic compromise and rhabdomyolysis can be life-saving in these patients.

Determinants of increased opioid-related mortality in the United States and Canada, 1990-2013: a systematic review

We review evidence of determinants contributing to increased opioid-related mortality in the United States and Canada between 1990 and 2013. We identified 17 determinants of opioid-related mortality and mortality increases that we classified into 3 categories: prescriber behavior, user behavior and characteristics, and environmental and systemic determinants. These determinants operate independently but interact in complex ways that vary according to geography and population, making generalization from single studies inadvisable. Researchers in this area face significant methodological difficulties; most of the studies in our review were ecological or observational and lacked control groups or adjustment for confounding factors; thus, causal inferences are difficult. Preventing additional opioid-related mortality will likely require interventions that address multiple determinants and are tailored to specific locations and populations.

Safe methadone induction and stabilization: report of an expert panel

OBJECTIVES

Methadone is a well-studied, safe, and effective medication when dispensed and consumed properly. However, a number of studies have identified elevated rates of overdose and death in patients being treated with methadone for either addiction or chronic pain. Among patients being treated with methadone in federally certified opioid treatment programs, deaths most often occur during the induction and stabilization phases of treatment. To address this issue, the federal Substance Abuse and Mental Health Services Administration invited the American Society of Addiction Medicine to convene an expert panel to develop a consensus statement on methadone induction and stabilization, with recommendations to reduce the risk of patient overdose or death related to methadone maintenance treatment of addiction.

METHODS

A comprehensive literature search of English-language publications (1979-2011) was conducted via MEDLINE and EMBASE. Methadone Action Group members evaluated the resulting information and collaborated in formulating the consensus statement presented here, which subsequently was reviewed by more than 100 experts in the field.

RESULTS

Published data indicate that deaths during methadone induction occur because the initial dose is too high, the dose is increased too rapidly, or the prescribed methadone interacts with another drug. Therefore, the Methadone Action Group has developed recommendations to help methadone providers avoid or minimize these risks.

CONCLUSIONS

Careful management of methadone induction and stabilization, coupled with patient education and increased clinical vigilance, can save lives in this vulnerable patient population.

Methadone-related deaths - epidemiological, pathohistological, and toxicological traits in 10-year retrospective study in Vojvodina, Serbia

The number of methadone-related deaths (MRDs) during a 10-year period (2002-2011) in the region of Vojvodina, Serbia, was increased. The cases were evaluated according to epidemiological parameters, pathohistological findings, and toxicological screening. The majority of victims were men, aged from 20 to 38. Pathohistologically, the signs of acute focal myocardial damage were present in the heart of victims with drug abuse history shorter than 2 years, while both signs of recent and chronic focal myocardial damage were developed among victims with longer drug abuse history (2-5 years). In postmortem blood samples of 54.84% of victims, methadone was detected in combination with diazepam, both in therapeutic range. Alcohol was absent in most cases. Other detected drugs were antipsychotics and antidepressants in therapeutic concentrations. These findings raise the attention to the concomitant use of methadone and benzodiazepines with the need for further studies to clarify the mechanism of death in such cases.

Mortality and causes of death among users of methadone maintenance treatment in Israel, 1999-2008

OBJECTIVES

To determine all-cause and specific-causes mortality, in the years 1999-2008, among opioid-dependent users treated at methadone maintenance treatment (MMT) clinics in Israel and to compare the obtained results with data from relevant studies worldwide.

METHOD

The records of patients treated at MMT units were linked to the nationwide database of causes of death. Information about the Israeli general population from the Central Bureau of Statistics was used for comparison to match sex and age to the cohort under study. Crude mortality rates (CMRs) per 100 persons per year (PY) and standardized mortality ratios (SMRs) with 95% confidence intervals (CIs) were calculated.

RESULTS

The overall CMR for MMT users was 1.49/100 PY (CI 1.40-1.59) and was not associated with gender, age at entering MMT, ethnicity, and immigrant status. The leading causes of mortality were sudden/undefined death (0.31/100 PY, CI 0.26-0.35), overdose (0.22/100 PY, CI 0.17-0.27), and cancer (0.15/100 PY, CI 0.12-0.18). The MMT users were 12.2 times more likely to die from all causes than people from the general population. Overall, our estimates were comparable with the figures pooled from relevant studies.

CONCLUSIONS

The results suggest that the excess mortality of MMT users is associated with an increased morbidity, which alone or in combination with service-related risks, lead to worse outcomes.