Non-fatal overdoses and related risk factors among people who inject drugs in St. Petersburg, Russia and Kohtla-Järve, Estonia

Injection Drug Use Frequency Before and After Take-Home Naloxone Training

Importance

Concerns that take-home naloxone (THN) training may lead to riskier drug use (as a form of overdose risk compensation) remain a substantial barrier to training implementation. However, there was limited good-quality evidence in a systematic review of the association between THN access and subsequent risk compensation behaviors.

Objective

To assess whether THN training is associated with changes in overdose risk behaviors, indexed through injecting frequency, in a cohort of people who inject drugs.

Design, Setting, and Participants

This cohort study used prospectively collected self-reported behavioral data before and after THN training of participants in The Melbourne Injecting Drug User Cohort Study (SuperMIX). Annual interviews were conducted in and around Melbourne, Victoria, Australia, from 2008 to 2021. SuperMIX participants were adults who regularly injected heroin or methamphetamine in the 6 months preceding their baseline interview. The current study included only people who inject drugs who reported THN training and had participated in at least 1 interview before THN training.

Exposure

In 2017, the SuperMIX baseline or follow-up survey began asking participants if and when they had received THN training. The first THN training date that was recorded was included as the exposure variable. Subsequent participant interviews were excluded from analysis.

Main Outcomes and Measures

Injecting frequency was the primary outcome and was used as an indicator of overdose risk. Secondary outcomes were opioid injecting frequency, benzodiazepine use frequency, and the proportion of the time drugs were used alone. Fixed-effects generalized linear (Poisson) multilevel modeling was used to estimate the association between THN training and the primary and secondary outcomes. Time-varying covariates included housing status, income, time in study, recent opioid overdose, recent drug treatment, and needle and syringe coverage. Findings were expressed as incidence rate ratios (IRRs) with 95% CIs.

Results

There were 1328 participants (mean [SD] age, 32.4 [9.0] years; 893 men [67.2%]) who completed a baseline interview in the SuperMIX cohort, and 965 participants completed either a baseline or follow-up interview in or after 2017. Of these 965 participants, 390 (40.4%) reported THN training. A total of 189 people who inject drugs had pretraining participant interviews with data on injecting frequency and were included in the final analysis (mean [SD] number of interviews over the study period, 6.2 [2.2]). In fixed-effects regression analyses adjusted for covariates, there was no change in the frequency of injecting (IRR, 0.91; 95% CI, 0.69-1.20; P = .51), opioid injecting (IRR, 0.95; 95% CI, 0.74-1.23; P = .71), benzodiazepine use (IRR, 0.96; 95% CI, 0.69-1.33; P = .80), or the proportion of reported time of using drugs alone (IRR, 1.04; 95% CI, 0.86-1.26; P = .67) before and after THN training.

Conclusions and Relevance

This cohort study of people who inject drugs found no evidence of an increase in injecting frequency, along with other markers of overdose risk, after THN training and supply. The findings suggest that THN training should not be withheld because of concerns about risk compensation and that advocacy for availability and uptake of THN is required to address unprecedented opioid-associated mortality.

Impact of COVID-19 & Response Measures on HIV-HCV Prevention Services and Social Determinants in People Who Inject Drugs in 13 Sites with Recent HIV Outbreaks in Europe, North America and Israel

HIV/HCV prevention among people who inject drugs (PWID) is of key public health importance. We aimed to assess the impact of COVID-19 and associated response measures on HIV/HCV prevention services and socio-economic status of PWID in high-HIV-risk sites. Sites with recent (2011-2019) HIV outbreaks among PWID in Europe North America and Israel, that had been previously identified, were contacted early May 2020. Out of 17 sites invited to participate, 13 accepted. Semi-structured qualitative site reports were prepared covering data from March to May 2020, analyzed/coded and confirmed with a structured questionnaire, in which all sites explicitly responded to all 103 issues reported in the qualitative reports. Opioid maintenance treatment, needle/syringe programs and antiretroviral treatment /hepatitis C treatment continued, but with important reductions and operational changes. Increases in overdoses, widespread difficulties with food and hygiene needs, disruptions in drug supply, and increased homelessness were reported. Service programs rapidly reformed long established, and politically entrenched, restrictive service delivery policies. Future epidemic control measures should include mitigation of negative side-effects on service provision and socio-economic determinants in PWID.

Public injecting and its association with mental health and other drug-related outcomes among people who inject drugs in Iran

BACKGROUND

Injecting in public places may increase the risk of drug and health-related harms among people who inject drugs (PWID). We examined the prevalence of public injecting and associations with non-fatal overdose, needle/syringe sharing, sexual health, and mental health among PWID in Iran.

METHODS

Using respondent-driven sampling, we recruited 2684 PWID from 11 major cities between July 2019 and March 2020. We defined public injecting as injecting primarily in public places, such as streets, parks, or abandoned buildings. Multivariable logistic regression models assessed public injecting and its associated factors, as well as the association of public injecting with certain health outcomes.

RESULTS

Of 2388 respondents, 69.6 % reported public injecting in the previous year. Self-identifying as men (adjusted odds ratio [aOR] = 4.21; 95 % confidence intervals [95 % CI]: 2.31, 7.65), homelessness (aOR = 6.81; 95 % CI: 5.10, 9.10), high injection frequency (aOR = 1.58; 95 % CI: 1.03, 2.44), and free needle/syringe uptake (aOR = 1.47; 95 % CI: 1.04, 2.07) were significantly associated with public injecting. Compared to PWID who primarily inject in non-public places, PWID who mostly used public places had significantly greater odds of reporting non-fatal overdose (aOR = 2.02; 95 % CI: 1.01, 4.02), needle/syringe sharing (aOR = 1.77; 95 % CI: 1.08, 2.90), unsafe sexual practices with casual sexual partners (aOR = 2.16; 95 % CI: 1.03, 4.55), suicidal ideation (aOR = 1.50; 95 % CI: 1.02, 2.21), and self-harm (aOR = 1.78; 95 % CI: 1.24, 2.54) in the last three months.

CONCLUSION

These results suggest the potential utility of a safer injecting environment to mitigate the multiple harms associated with public injecting in Iran. Optimizing health and well-being of PWID necessitates integrating supervised injection facilities into the current harm reduction programs and services in Iran. Future studies should also consider the experiences of additional mental health harms associated with public injecting when exploring adverse health outcomes among PWID.

Identifying key risk factors for premature discontinuation of opioid use disorder treatment in the United States: A predictive modeling study

BACKGROUND

Treatment for opioid use disorder (OUD), particularly medication for OUD, is highly effective; however, retention in OUD treatment is a significant challenge. We aimed to identify key risk factors for premature exit from OUD treatment.

METHODS

We analyzed 2,381,902 cross-sectional treatment episodes for individuals in the U.S., discharged between Jan/1/2015 and Dec/31/2019. We developed classification models (Random Forest, Classification and Regression Trees (CART), Bagged CART, and Boosted CART), and analyzed 31 potential risk factors for premature treatment exit, including treatment characteristics, substance use history, socioeconomic status, and demographic characteristics. We stratified our analysis based on length of stay in treatment and service setting. Models were compared using cross-validation and the receiver operating characteristic area under the curve (ROC-AUC).

RESULTS

Random Forest outperformed other methods (ROC-AUC: 74%). The most influential risk factors included characteristics of service setting, geographic region, primary source of payment, and referral source. Race, ethnicity, and sex had far weaker predictive impacts. When stratified by treatment setting and length of stay, employment status and delay (days waited) to enter treatment were among the most influential factors. Their importance increased as treatment duration decreased. Notably, importance of referral source increased as the treatment duration increased. Finally, age and age of first use were important factors for lengths of stay of 2-7 days and in detox treatment settings.

CONCLUSIONS

The key factors of OUD treatment attrition identified in this analysis should be more closely explored (e.g., in causal studies) to inform targeted policies and interventions to improve models of care.

HIV seroprevalence in five key populations in Europe: a systematic literature review, 2009 to 2019

Background

In Europe, HIV disproportionately affects men who have sex with men (MSM), people who inject drugs (PWID), prisoners, sex workers, and transgender people. Epidemiological data are primarily available from national HIV case surveillance systems that rarely capture information on sex work, gender identity or imprisonment. Surveillance of HIV prevalence in key populations often occurs as independent studies with no established mechanism for collating such information at the European level.

Aim

We assessed HIV prevalence in MSM, PWID, prisoners, sex workers, and transgender people in the 30 European Union/European Economic Area countries and the United Kingdom.

Methods

We conducted a systematic literature review of peer-reviewed studies published during 2009–19, by searching PubMed, Embase and the Cochrane Library. Data are presented in forest plots by country, as simple prevalence or pooled across multiple studies.

Results

Eighty-seven country- and population-specific studies were identified from 23 countries. The highest number of studies, and the largest variation in HIV prevalence, were identified for MSM, ranging from 2.4–29.0% (19 countries) and PWID, from 0.0–59.5% (13 countries). Prevalence ranged from 0.0–15.6% in prisoners (nine countries), 1.1–8.5% in sex workers (five countries) and was 10.9% in transgender people (one country). Individuals belonging to several key population groups had higher prevalence.

Conclusion

This review demonstrates that HIV prevalence is highly diverse across population groups and countries. People belonging to multiple key population groups are particularly vulnerable; however, more studies are needed, particularly for sex workers, transgender people and people with multiple risks.

Drug type and risk behaviors associated with non-fatal overdose among people who use drugs: a systematic review and meta-analysis

The present study aimed to determine the association between drug type, risk behaviors and non-fatal overdose among people who use drugs (PWUD). We searched for studies in English published before February 1, 2021, on PubMed, Scopus, Cochrane, and Web of Science to identify primary studies on the factors associated with non-fatal overdose among PWUD. After reviewing for study duplicates, the full-text of selected articles were assessed for eligibility using Population, Intervention, Comparator, Outcomes (PICO) criteria. After a detailed assessment of over 13,845 articles, a total of 49 studies met the eligibility criteria. We found that non-injection opioid use, heroin injection, cocaine use, concurrent use of buprenorphine and benzodiazepines, benzodiazepine use, incarceration, injecting drugs, and duration of injecting were associated with greater odds of non-fatal overdose among PWUD. The findings of the current meta-analysis support the requirement to improve suitable harm reduction strategies for drug users, such as peer-based overdose management, and further focusing on the need to balance the current emphasis on enforcement-based responses to illegal drug use with health-related interventions.

Prevalence and correlates of simultaneous, multiple substance injection (co-injection) among people who inject drugs in Melbourne, Australia

AIMS

To estimate the prevalence of and risk factors associated with concurrent injection of multiple substances (co-injection) among a community-recruited cohort of people who inject drugs.

DESIGN

Cross-sectional study.

SETTING

Melbourne, Australia.

PARTICIPANTS

A sample of 720 actively injecting participants from the Melbourne Injecting Drug User Cohort Study (33% female) was extracted.

MEASUREMENTS

We constructed two statistical models: a logistic regression model analysing correlates of co-injection of any substance combination in the past month and a multinomial logistic regression model analysing correlates of three mutually exclusive groups: heroin-diphenhydramine co-injection only, co-injection of other substances and no co-injection. Risk factors examined included drug use characteristics, demographic characteristics, health service use, hepatitis C status, injection risk behaviours and previous experience of non-fatal overdose.

FINDINGS

One-third [n = 226, 31%; 95% confidence interval (CI): 28-34%] of participants reported co-injecting substances within the past month, with equal numbers of participants reporting injecting combinations of heroin-diphenhydramine (n = 121, 54%; 95% CI = 48-60%) and heroin-methamphetamine (n = 121, 54%; 95% CI = 48-60%). In logistic regression analyses, reporting co-injection of any substance combination was associated with male sex [adjusted odds ratio (aOR) = 1.80, 95% CI = 1.18-2.74, P = 0.006] and injecting daily or more frequently (aOR = 2.04, 95% CI = 1.31-3.18, P = 0.002). In multinomial logistic regression analyses, participants reporting heroin-diphenhydramine co-injection only were significantly more likely to report groin injecting [adjusted relative risk ratio (aRRR) = 6.16, 95% CI = 2.80-13.56, P < 0.001] and overdose (requiring an ambulance) in the past 12 months (aRRR = 2.81, 95% CI = 1.17-6.72, P = 0.021) compared with participants reporting no co-injection or co-injection of other substances.

CONCLUSIONS

A substantial proportion of people who inject drugs report co-injection of multiple substances, which is associated with a range of socio-demographic, drug use and health service use risk factors.

Past 12-month nonfatal overdose among people who inject drugs in Ukraine: City-level estimates and risk factors from a cross-sectional study

BACKGROUND

Nonfatal overdose contributes to high morbidity and is among the strongest proxies for the occurrence of overdose fatality - the leading cause of death among those who use opioids. In Ukraine, a majority of people who inject drugs (PWID) use opioids, but little is known about the relationship between drug market characteristics, nonfatal overdose (NFOD) prevalence, and risk factors for NFOD.

METHODS

We used cross-sectional respondent-driven sampling (RDS) data to explore the variability of recent (past 12 months) NFOD among PWID across Ukrainian cities and associations with individual factors. The population-averaged -cross-sectional associations were estimated and compared using generalized linear models for the binary outcome (NFOD vs. not) with robust variance estimates.

RESULTS

Recent self-reported NFOD varied between 1% and 14 % across Ukrainian cities. In adjusted analyses, overdose was associated with fewer years of injecting drugs; a higher number of types of drugs used in the past 12 months; using desomorphine, methadone, tramadol, heroin, amphetamine-type drugs or cocaine within past 12 months; using alcohol daily or weekly; recent drug treatment; and history of incarceration. Buying drugs or their ingredients through "stashes" (i.e., drugs secretly hidden in various places) and the perception of drug price increase were associated with higher odds of reporting NFOD.

CONCLUSION

The identified risk factors underscore the importance of evidence-based prevention efforts, such as scaling-up opioid agonist therapy, providing naloxone in the community and upon prison release, targeting those most likely to witness overdose and sharing overdose prevention strategies with them, and continuous monitoring of trends and contributing factors.

DARK Classics in Chemical Neuroscience: Krokodil

Krokodil is the street name for a homemade mixture that has been used as a cheap substitute for heroin. The main active substance in krokodil is desomorphine, an opioid that is 10 times more potent than morphine. Krokodil use began in Russia and Ukraine but has spread throughout several countries in Europe and North America. Krokodil is produced from codeine tablets in a bootleg reaction performed under clandestine and unsanitary conditions. The toxicity of krokodil is characterized by devastating symptoms that start as black ulcers at the injection site and evolve to gangrene and limb amputation. The dangerous effects of krokodil are associated with its homemade nature and lack of purification prior to use. In this review, we discuss the chemical and pharmacological properties and the metabolism of desomorphine, the preparation of krokodil, and how its homemade nature contributes to its toxicity. The synthesis of krokodil produces several other morphinans in addition to desomorphine that warrant further study as possible analgesic alternatives to morphine.

The fentanyl epidemic in Estonia: factors in its evolution and opportunities for a comprehensive public health response, a scoping review

BACKGROUND

The spread of illicitly manufactured fentanyl has the potential to greatly increase the fatal overdoses in many places in the world. The purpose of this paper is to analyse the evolution of fentanyl use epidemic in Estonia.

METHODS

this scoping review is based on extensive review and synthesis of broad range of literature: research reports, newspaper, magazine, coverage of illicit fentanyl use; policy documents, position papers, reports released by government agencies, and surveillance data.

RESULTS

For an over a decade up to 2017, Estonia has had the highest overdose death mortality in Europe. The use of (injected) fentanyl is a major contributor to the Estonian overdose death epidemic. Shutting down a major producer and distributor of illicit fentanyl has been extremely effective in curbing the number of overdose deaths. Unfortunately, this supply-side intervention came ten years into the epidemic, and might be difficult to replicate in settings with decentralized production. In areas faced by fentanyl we would recommend large-scale implementation of opiate substitution treatment and naloxone distribution, syringe service programs to provide for safer injecting and link to other services (high frequencies of fentanyl injection create high risk for HIV and HCV transmission), and programs, such as "Break the Cycle," to reduce initiation into injecting drug use. Further, the means of responding to emerging substances should match the world in which different substances can be rapidly introduced, and where people who use drugs can change preferences based on market availability.

CONCLUSION

Addressing illicitly manufactured fentanyl may serve as a public health learning experience for developing early detection and rapid response programs in rapidly changing drug use environments.

Understanding Naloxone Uptake from an Emergency Department Distribution Program Using a Low-Energy Bluetooth Real-time Location System

INTRODUCTION

Emergency department (ED)-based naloxone distribution programs are a widespread harm reduction strategy. However, data describing the community penetrance of naloxone distributed from these programs are lacking. This study gauges acceptance of naloxone use and monitoring technology among people who use drugs (PWUD), and explores the use of real-time location systems (RTLS) in monitoring naloxone movements.

METHODS

A prospective observational study was conducted on a convenience sample of individuals (N = 30) presenting to a tertiary-care academic medical center ED for an opioid-related complaint. A naloxone kit equipped with a low-energy Bluetooth (BLE) tracking system was employed to detect movement of naloxone off the hospital campus as a proxy for community penetrance, followed by a qualitative interview to gauge participant acceptance of naloxone use and monitoring technology.

RESULTS

Detection of BLE signals verified transit of 24 distributed naloxone kits off our hospital campus. Three participants whose BLE signals were not captured reported taking their kits with them following discharge, suggesting technological errors occurred; another three participants were lost to follow-up. Qualitative interviews demonstrated that participants accepted ED-based naloxone distribution programs and passive tracking technologies, but revealed concerns regarding hypothetical continuous monitoring systems and problematic interactions with first responders and law enforcement personnel.

CONCLUSIONS

Based on acquired BLE signals, 80% of dispensed naloxone kits left the hospital campus. Use of RTLS to passively geolocate naloxone rescue kits is feasible, but detection can be adversely affected by technological errors. PWUD are amenable to transient monitoring technologies but identified barriers to implementation.

A Pilot Study of a Telemedicine-based Substance Use Disorder Evaluation to Enhance Access to Treatment Following Near-Fatal Opioid Overdose

The opioid epidemic is a growing public health emergency in the United States, with deaths from opioid overdose having increased five-fold since 1999. Emergency departments (EDs) are the primary sites of medical care after near-fatal opioid overdose but are poorly equipped to provide adequate substance use treatment planning prior to discharge. In many underserved locales, limited access to clinicians trained in addiction medicine and behavioral health exacerbates this disparity. In an effort to improve post-overdose care in the ED, we developed a telemedicine protocol to facilitate timely access to substance use disorder evaluations. In this paper, we describe the conception and refinement of the telemedicine program, our experience with the first 20 participants, and potential implications of the platform on health disparities for individuals with opioid use disorder.

Concurrent Alcohol and Opioid Use Among Harm Reduction Clients

BACKGROUND

Harm reduction services infrequently address alcohol use among clients using opioids, despite the evaluated risk of overdose or medical consequences for clients with viral infections. The purpose of this study is to assess concurrent alcohol and opioid use among syringe services and overdose prevention program participants predominately in southern Ohio and northern Kentucky.

METHODS

This is a cross-sectional study using self-report data (n = 1,142) pooled across regional overdose prevention programs and a mobile syringe services program. The outcome variable was concurrent use categorized as no concurrent alcohol, prescription opioid or heroin use; alcohol and heroin or prescription opioid use; and alcohol, prescription opioid and heroin use in the past three months.

RESULTS

The sample was predominantly white (95%), 56% were male and the mean age was 33 years old. Forty-seven percent of the clients had no concurrent use of alcohol and opioids; 20.1% reported concurrent use of alcohol and either heroin or prescription opioids; and 33.4% reported concurrent use of alcohol, heroin and prescription opioids in the past 3 months. Lifetime suicidal ideation and non-opioid drug use were associated with concurrent alcohol and opioid use in the multivariable model.

CONCLUSION

Harm reduction clients with concurrent alcohol and opioid use may warrant enhanced overdose prevention services. Syringe services and overdose prevention program participants may benefit from education or a brief intervention on alcohol consumption.

A New Generation of Drug Users in St. Petersburg, Russia? HIV, HCV, and Overdose Risks in a Mixed-Methods Pilot Study of Young Hard Drug Users

Russia has a widespread injection drug use epidemic with high prevalence of HIV and HCV among people who inject drugs (PWID). We conducted a mixed methods study of young (age 18-26) hard drug users in St. Petersburg. Thirty-nine structured and 10 semi-structured interviews were conducted. No HIV cases and two HCV cases were detected among the PWID subsample (n = 29). Amphetamine and other stimulants were common (70%), opioid use was rare and episodic. Consistent condom use was 10%. No PWID reported syringe-sharing, 51% reported other drug paraphernalia sharing. Most (89%) never or rarely communicated with older (30 +) opiate users. A new cohort of drug users in St. Petersburg may have emerged, which is much safer in its injection practices compared to previous cohorts. However, risky sexual practices among this new cohort may expose them to the possibility of sexual transmission of HIV and widespread drug paraphernalia sharing to the HCV epidemic.

The rising crisis of illicit fentanyl use, overdose, and potential therapeutic strategies

Fentanyl is a powerful opioid anesthetic and analgesic, the use of which has caused an increasing public health threat in the United States and elsewhere. Fentanyl was initially approved and used for the treatment of moderate to severe pain, especially cancer pain. However, recent years have seen a growing concern that fentanyl and its analogs are widely synthesized in laboratories and adulterated with illicit supplies of heroin, cocaine, methamphetamine, and counterfeit pills, contributing to the exponential growth in the number of drug-related overdose deaths. This review summarizes the recent epidemic and evolution of illicit fentanyl use, its pharmacological mechanisms and side effects, and the potential clinical management and prevention of fentanyl-related overdoses. Because social, economic, and health problems that are related to the use of fentanyl and its analogs are growing, there is an urgent need to implement large-scale safe and effective harm reduction strategies to prevent fentanyl-related overdoses.

Prevalence of injecting drug use in Estonia 2010-2015: a capture-recapture study

Background

It has been observed in an earlier study that the number of people who inject drugs (PWID) in Estonia is declining. We provide nationwide estimates of the number of PWID in Estonia for years 2010–2015 and compare different modelling strategies to minimise over-coverage-induced bias in capture-recapture estimates.

Methods

We obtained data from the Estonian Causes of Death Registry (DR) for opioid-related deaths, the Estonian Health Insurance Fund (HIF) for opioid-related overdose and drug dependence treatment episodes, and the Estonian Police and Border Guard Board (PB) drug-related misdemeanours. Datasets were linked by identifier based on sex, date of birth, and initials; a capture-recapture method was used to estimate the number of PWID aged 15 or more, each year from 2010 to 2015. Log-linear regression maximum likelihood (ML) and Bayesian methods were used; over-coverage of police data was accounted for.

Results

The annual population size estimates of the number of PWID (aged 15 and over) varied from 6000 to 17,300 (ML estimates not accounting for over-coverage of PB) to 1500–2300 (Bayesian estimates accounting for over-coverage). Bayesian estimates indicated a slight decrease in the number of PWID, and the median estimates were > 2000 in years 2010–2012 and < 1800 in years 2013–2015.

Conclusions

Over-coverage of a registry can have a great impact on the estimates of the size of the target population. Bayesian estimates accounting for this over-coverage may provide better estimates of the target population size.

Electronic supplementary material

The online version of this article (10.1186/s12954-019-0289-3) contains supplementary material, which is available to authorized users.

Assessing the 2004-2018 Fentanyl Misusing Issues Reported to an International Range of Adverse Reporting Systems

Objective: A recent, global, increase in the use of opioids including the prescribing, highly potent, fentanyl has been recorded. Due its current popularity and the potential lethal consequences of its intake, we aimed here at analyzing the fentanyl misuse, abuse, dependence and withdrawal-related adverse drug reactions (ADRs) identified within the European Medicines Agency (EMA), the United Kingdom Yellow Card Scheme (YCS), and the United States Food and Drug Administration (FDA) Adverse Event Reporting System (FAERS) databases. Methods: Descriptive analysis of both ADRs and related cases. Results: The analysis of fentanyl-related misuse, abuse, dependence and withdrawal cases reported during years 2004-2018 to the EMA, the YCS, and the FAERS showed increasing levels overtime, specifically, EMA-related data presented two peaks (e.g., in 2008 and 2015), whilst the FAERS dataset was characterized by a dramatic increase of the ADRs collected over the last 18 months, and particularly from 2016. Some 127,313 ADRs (referring to n = 6,161 patients/single cases) related to fentanyl's misuse/abuse/dependence/withdrawal issues were reported to EMA, with 14,287 being judged by the reporter as "suspect." The most represented ADRs were: "drug dependence "(76.87%), "intentional product misuse" (13.06%), and "drug abuse" (7.45%). Most cases involved adult males and the concomitant use of other prescribing/illicit drugs. A range of idiosyncratic (i.e., ingestion/injection of transdermal patches' fentanyl) and very high-dosage intake cases were here identified. Significant numbers of cases required either a prolonged hospitalization (192/559 = 34.35%) or resulted in death (185/559 = 33.09%). Within the same time frame, YCS collected some 3,566 misuse/abuse/dependence/withdrawal ADRs, corresponding to 1,165 single patients/cases, with those most frequently reported being "withdrawal," "intentional product misuse," and "overdose" ADRs. Finally, FAERS identified a total of 19,145 misuse/abuse/dependence/withdrawal-related cases, being "overdose," withdrawal, and "drug use disorder/drug abuse/drug diversion" the most represented ADRs (respectively, 43.11, 20.80, and 20.29%). Conclusion: Fentanyl abuse may be considered a public health issue with significant implications for clinical practice. Spontaneous pharmacovigilance reporting systems should be considered for mapping new trends of drug abuse.

Overdose mortality rates in Croatia and factors associated with self-reported drug overdose among persons who inject drugs in three Croatian cities

BACKGROUND

Drug overdose is the major cause of morbidity and mortality among persons who inject drugs (PWID). We assessed factors associated with the non-fatal drug overdose among PWID in three Croatian cities and national trends of overdose-related mortality (OM), and rates of uptake of opioid agonist drug treatment (OAT).

METHODS

We used a respondent-driven sampling method to recruit 830 PWID in Zagreb, Split and Rijeka in 2014/2015. Participants completed behavioural questionnaires that included questions about overdose history, and we used Poisson regression to assess factors associated with self-reported overdose. We used joinpoint regression to calculate national trends of OM from 2001 to 2015 and rates of uptake of drug treatment from 2005 to 2015.

RESULTS

Lifetime prevalence of self-reported drug overdose in our RDS sample was 45.2%, while 4.1% of PWID reported overdose in the past 12 months; PWID who injected more than one type of drug in the past 12 months (adjusted prevalence ratio [aPR] = 4.56, 95% confidence intervals [CI] = 1.35-15.38) compared to injecting only heroin, and those enrolled in OAT (aPR = 1.94, 95% CI = 1.01-3.74) were more likely to report overdose in the past 12 months. We observed an increase in annual percent change (APC) of the national OM rates from 2001 to 2007 (APC = 22.5%, 95% CI = 16.3-29.0) and a decline from 2007 to 2015 (APC = -8.0%, 95% CI = -5.3- -10.5). The national rates of drug treatment enrollment increased from 2005 to 2010 (APC = 12.0%, 95% CI = 10.3-13.8), mostly due to increase in provision of buprenorphine from 2005 to 2008 (APC = 130.4%, 95% CI = 102.1-162.7).

CONCLUSION

Injecting more than one type of drugs and enrollment in OAT while still injecting drugs was positively associated with non-fatal overdose in our sample. To further reduce OM in Croatia we suggest improvements in coverage and delivery of OAT and establishment of provision of naloxone for PWID.

New synthetic opioids: Part of a new addiction landscape

Synthetic opioids (SO) are a major risk for public health across the world. These drugs can be divided into 2 categories, pharmaceutical and non-pharmaceutical fentanyls. A new generation of SO has emerged on the drug market since 2010. North America is currently facing an opioid epidemic of morbi-mortality, caused by over-prescription of opioids, illegally diverted prescribed medicines, the increasing use of heroin and the emergence of SO. Furthermore, this opioid crisis is also seen in Europe. SO are new psychoactive substances characterized by different feature such as easy availability on the Internet, low price, purity, legality, and lack of detection in laboratory tests. They have not been approved or are not recommended for human use. Opioid misuse is associated with somatic and psychiatric complications. For many substances, limited pharmacological information is available, increasing the risk of harmful adverse events. Health actors and the general population need to be clearly informed of the potential risks and consequences of the diffusion and use of SO.

Polydrug Use and Heterogeneity in HIV Risk Among People Who Inject Drugs in Estonia and Russia: A Latent Class Analysis

Non-medical drug injection is a major risk factor for HIV infection in Russia and Estonia. Multiple drug use (polydrug) has further been associated with increased harms. We compared HIV, injecting and sexual risk associated with polydrug use among people who injected drugs (PWID) in 2012–2013 in Kohtla-Järve (Estonia, n = 591) and St Petersburg (Russia, n = 811). Using latent class analysis, we identified five (poly)drug classes, the largest consisting of single-drug injectors among whom an opioid was the sole drug injected (56% of PWID). The four remaining polydrug classes included polydrug-polyroute injectors who injected and used opiates and stimulants (9%), opiate-stimulant poly-injectors who injected amphetamine-type-stimulants with a primary opiate (7%) and opiate-opioid poly-injectors who injected opioids and opiates (16%). Non-injection stimulant co-users were injectors who also used non-injection stimulants (12%). In multivariable multinomial regressions, all four polydrug classes were associated with greater injection risks than single-drug injection, while opiate-stimulant and opiate-opioid poly-injection were also associated with having multiple sex partners. Riskier behaviours among polydrug-injectors suggest increased potential for transmission of blood-borne and sexually-transmitted infections. In addition to needles/syringes provision, services tailored to PWID drug and risk profiles, could consider drug-appropriate treatment and sexual risk reduction strategies to curb HIV transmission.

Effect of ageing and time since first heroin and cocaine use on mortality from external and natural causes in a Spanish cohort of drug users

BACKGROUND

We aimed to assess the effect of ageing and time since first heroin/cocaine use on cause-specific mortality risk and age disparities in excess mortality among heroin (HUs) and cocaine users (CUs) in Spain.

METHODS

A cohort of 15,305 HUs and 11,905 CUs aged 15-49 starting drug treatment during 1997-2007 in Madrid and Barcelona was followed until December 2008. Effects of ageing and time since first heroin/cocaine use were estimated using a competing risk Cox model and the relative and absolute excess mortality compared to the general population through directly age-sex standardized rate ratios (SRRs) and differences (SRDs), respectively.

RESULTS

Mortality risk from natural causes increased with time since first heroin use, whereas that from overdose declined after having peaked in the first quinquennium. Significant effects of time since first cocaine use were not identified, although fatal overdose risk seemed higher in CUs after five years. Mortality risk from natural causes (HUs and CUs), injuries (HUs), and overdoses (CUs) increased with age, the latter without reaching statistical significance. Crude mortality rates from overdoses and injuries remained very high at age 40-59 among both HUs (595 and 217 deaths/100,000 person-years, respectively) and CUs (191 and 88 deaths/100,000 person-years). SRDs from all and natural causes were much higher at age 40-59 than 15-29 in both HUs (2134 vs. 834 deaths/100,000 person-years) and CUs (927 vs. 221 deaths/100,000 person-years), while the opposite occurred with SRRs.

CONCLUSION

The high mortality risk among HUs and CUs at all ages from both external and natural causes, and increased SRDs with ageing, suggest that high-level healthcare and harm reduction services should be established early and maintained throughout the lifetime of these populations.

Perceived effectiveness of antiretroviral therapy, self-rated health and treatment adherence among HIV-positive people who inject drugs in Estonia

The HIV epidemic in Estonia affects the population of people who inject drugs (PWID) the most, but factors associated with adherence to antiretroviral therapy (ART) among PWID have not been thoroughly examined in Estonia, with particularly limited data regarding beliefs and attitudes of PWID. The objective of this study was to explore the association between ART adherence and individual beliefs, perceived effectiveness of ART, and self-rated health in particular, in this specific population. The study used baseline survey data from a longitudinal intervention study of HIV prevention among PWID in Estonia, in which 107 HIV-infected participants reported current use of ART. Current adherence was measured through the use of a visual analog scale. Approximately half (49%) of the participants reported optimal (≥95%) adherence. The vast majority (81%) believed in the effectiveness of ART. Less than a quarter of the participants (22%) rated their health as good or very good, and a half (52%) reported average health. Individual beliefs and self-reported health were not associated with ART adherence in both bivariate and multivariable analyses. Participants with problem drinking reported significant suboptimal adherence to ART (adjusted odds ratio [AOR] 0.42, 95% CI 0.19-0.97). Daily injection drug use was also associated with suboptimal adherence (AOR 0.34, 95% CI 0.13-0.91). Problem drinking has not been commonly reported as a factor of suboptimal ART adherence among PWID; further research would be useful to identify the pathways that might be involved.