Patterns of drug use among people who inject drugs: A global systematic review and meta-analysis.

BACKGROUND: A better understanding of global patterns of drug use among people who inject drugs can inform interventions to reduce harms related to different use profiles. This review aimed to comprehensively present the geographical variation in drug consumption patterns among this population. METHODS: Systematic searches of peer reviewed (PsycINFO, Medline, Embase) and grey literature published from 2008-2022 were conducted. Data on recent (past year) and lifetime drug use among people who inject drugs were included. Data were extracted on use of heroin, amphetamines, cocaine, benzodiazepines, cannabis, alcohol, and tobacco; where possible, estimates were disaggregated by route of administration (injecting, non-injecting, smoking). National estimates were generated and, where possible, regional, and global estimates were derived through meta-analysis. RESULTS: Of 40,427 studies screened, 394 were included from 81 countries. Globally, an estimated 78.1 % (95 %CI:70.2-84.2) and 71.8 % (65.7-77.2) of people who inject drugs had recently used (via any route) and injected heroin, while an estimated 52.8 % (47.0-59.0) and 19.8 % (13.8-26.5) had recently used and injected amphetamines, respectively. Over 90 % reported recent tobacco use (93.5 % [90.8-95.3]) and recent alcohol use was 59.1 % (52.6-65.6). In Australasia recent heroin use was lowest (49.4 % [46.8-52.1]) while recent amphetamine injecting (64.0 % [60.8-67.1]) and recent use of cannabis (72.3 % [69.9-74.6]) were higher than in all other regions. Recent heroin use (86.1 % [78.3-91.4]) and non-injecting amphetamine use (43.3 % [38.4-48.3]) were highest in East and Southeast Asia. Recent amphetamine use (75.8 % [72.7-78.8]) and injecting heroin use (84.8 % (81.4-87.8) were highest in North America while non-injecting heroin use was highest in Western Europe (45.0 % [41.3-48.7]). CONCLUSION: There is considerable variation in types of drugs and routes of administration used among people who inject drugs. This variation needs to be considered in national and global treatment and harm reduction interventions to target the specific behaviours and harms associated with these regional profiles of use.

A retrospective study of the characteristics and toxicology of cases of lysergic acid diethylamide (LSD)- and psilocybin-related death in Australia.

BACKGROUND AND AIMS: Lysergic acid diethylamide (LSD) and psilocybin are used as recreational drugs, and there is renewed interest in their clinical use. The current study aimed to (1) determine the circumstances of death and case characteristics of LSD- and psilocybin-related death in Australia, 2000-23; and (2) determine the toxicological profile and major autopsy findings of these cases. METHODS: This was a retrospective exploratory study of all cases of LSD- and psilocybin-related death in Australia, 2000-23, retrieved from the National Coronial Information System. RESULTS: A total of 43 cases were identified: 33 LSD and 10 psilocybin. The median ages were 24 years [interquartile range (IQR) = 13, range = 16-53] (LSD) and 26 years (IQR = 18.5, range = 20-58) (psilocybin), and fewer than five cases were female. The most common circumstance of death among both groups was traumatic accident (LSD 36.4%, psilocybin 40.0%). There were 12 cases of self-harm, all of which involved LSD, all by physical means. In a fifth, death was attributed to multiple drug toxicity (LSD 18.2%, psilocybin 20.0%). In one case, death was attributed solely to LSD toxicity, while in a further two cases death was attributed to a cardiovascular event following LSD consumption (one LSD only, one multiple drug toxicity). In four psilocybin cases, the cause of death was undetermined. The most common clinical presentation was severe agitation (LSD 27.3%, psilocybin 20.0%). Median blood concentrations were LSD 0.8 µg/l (IQR = 1.7, range = 0.1-3), psilocin 20 µg/l (IQR = 53.5, range = 6-83). LSD was the only drug present in 25.0% of LSD cases and psilocybin in 20.0% of psilocybin cases. Pre-existing organ pathology was uncommon. CONCLUSIONS: Lysergic acid diethylamide (LSD)- and psilocybin-related death in Australia from 2000 to 2023 was primarily due to traumatic injury, whether through accident or self-harm. Cases of acute toxic reactions that were attributed solely to LSD were rare.

Stigma, and factors associated with experiencing stigma, while visiting health-care services among samples of people who use illegal drugs in Australia.

INTRODUCTION: People who inject drugs experience stigma across multiple settings, including when accessing health-care services, however, comparatively little is known about experiences of stigma towards other groups of people who use illegal drugs. This paper examines experience of, and factors associated with, stigma among two samples of people who use illegal drugs when visiting both specialist alcohol and other drug (AOD) and general health-care services. METHODS: Australians who regularly (i.e., ≥monthly) inject drugs (n = 879; illicit drug reporting system [IDRS]) or use ecstasy and/or other illegal stimulants (n = 700; ecstasy and related drugs reporting system [EDRS]) were surveyed between April and July 2022 about past 6-month experience of stigma in the above services. Multi-variable regression analyses were performed to determine the socio-demographic, drug use and health factors associated with stigma. RESULTS: Experiences of stigma in general health-care services were more common among IDRS (40%) than EDRS (24%; p < 0.001) participants, however, experiences were comparable in specialist AOD health-care settings (22% and 20%, respectively; p = 0.687). Gender identity and experiencing high psychological distress were associated with experiencing stigma across both samples. Past-year overdose was associated with experiencing stigma among the IDRS sample, while unstable housing and incomplete high school education were associated with experiencing stigma in the EDRS sample. DISCUSSION AND CONCLUSIONS: Experiences of stigma when accessing health-care services are relatively common across different populations of people who use illegal drugs. Our findings highlight the multiple and intersecting dimensions of stigma and provide further support for recent calls for a universal precautions approach to stigma in health care.

Transitions to polysubstance use: Prospective cohort study of adolescents in Australia.

BACKGROUND AND AIMS: Adolescent polysubstance use has been associated with adverse social and health outcomes. Our aim was to measure rates and transitions to polysubstance use during adolescence and identify factors associated with initiation and discontinuation of polysubstance use. DESIGN: Prospective cohort study. Multistate Markov modelling was used to estimate rates and identify correlates of transitions between substance use states. SETTING AND PARTICIPANTS: Adolescent-parent dyads (n = 1927; adolescents in grade 7, age ≈13 years) were recruited from Australian schools during 2010/11 (Wave 1). Adolescents were surveyed annually until 2016/17 (n = 1503; age ≈19 years; Wave 7) and parents were surveyed annually until 2014/15 (Wave 5). MEASUREMENTS: Alcohol, tobacco, cannabis and 3,4-methylenedioxymethamphetamine (MDMA) use outcomes were collected at Waves 3-7. Potential confounders were collected at Waves 1-6 and consisted of sex, anxiety and depression symptoms and externalizing problems, parental monitoring, family conflict and cohesion, parental substance use and peer substance use. Covariates were age and family socioeconomic status. FINDINGS: Few adolescents engaged in polysubstance use at earlier waves (Wave 3: 5%; Wave 4: 8%), but proportions increased sharply across adolescence (Waves 5-7: 17%, 24%, 36%). Rates of transitioning to polysubstance use increased with age, with few (<9%) adolescents transitioning out. More externalizing problems (odds ratio [OR] = 1.10; 99.6% confidence interval [CI] = 1.07-1.14), parental heavy episodic drinking (OR = 1.22; 99.6% CI = 1.07-1.40), parental illicit substance use (OR = 3.56; 99.6% CI = 1.43-8.86), peer alcohol use (OR = 5.68; 99.6% CI = 1.59-20.50) and peer smoking (OR = 4.18; 99.6% CI = 1.95-8.81) were associated with transitioning to polysubstance use. CONCLUSIONS: Polysubstance use in Australia appears to be rare during early adolescence but more common in later adolescence with low rates of transitioning out. Externalizing problems and greater parental and peer substance use are risk factors for adolescent polysubstance use that may be suitable intervention targets.

Vaccination coverage among people who inject drugs: A systematic review.

BACKGROUND: People who inject drugs may be at excess risk of acquiring vaccine-preventable diseases and negative associated health outcomes, but experience barriers to vaccination. We aimed to determine vaccination coverage among people who inject drugs globally. METHODOLOGY: We conducted systematic searches of the peer-reviewed and grey literature, date limited from January 2008 to August 2023, focusing on diseases for which people who inject drugs are at elevated risk for and for which an adult vaccination dose is recommended (COVID-19, hepatitis A, hepatitis B, human papillomavirus, influenza, pneumococcal disease, tetanus). To summarise available data, we conducted a narrative synthesis. RESULTS: We included 78 studies/reports comprising 117 estimates of vaccination coverage across 36 countries. Most estimates were obtained from high income countries (80%, n=94). We located estimates for hepatitis B vaccination in 33 countries, which included 18 countries with data on serological evidence of vaccine-derived hepatitis B immunity (range: 6-53%) and 22 countries with self-report data for vaccine uptake (<1-96%). Data for other vaccines were scarcer: reported hepatitis A vaccination coverage ranged 3-89% (five countries), COVID-19 ranged 4-84% (five countries), while we located estimates from fewer than five countries for influenza, tetanus, pneumococcal disease, and human papillomavirus. CONCLUSION: Estimates were sparse but where available indicative of suboptimal vaccination coverage among people who inject drugs. Improving the consistency, timeliness, and geographic coverage of vaccine uptake data among this population is essential to inform efforts to increase uptake.

High COVID-19 vaccine uptake following initial hesitancy among people in Australia who inject drugs.

BACKGROUND: Previous studies have reported high COVID-19 vaccine hesitancy among people who inject drugs. We aimed to examine COVID-19 vaccine coverage, motivations and barriers to vaccination, and factors associated with uptake among this population in Australia, 1.5 years after vaccine rollout commenced. METHODS: In June-July 2022, 868 people (66.0 % male, mean age 45.6 years) who regularly inject drugs and reside in an Australian capital city reported the number of COVID-19 vaccine doses they had received and their primary motivation (if vaccinated) or barrier (if unvaccinated) to receive the vaccine. We compared vaccine uptake to Australian population estimates and used logistic regression to identify factors associated with ≥ 2 dose and ≥ 3 dose uptake. RESULTS: Overall, 84.1 % (n = 730) had received at least one COVID-19 vaccine dose, 79.6 % (n = 691) had received ≥ 2 doses, and 46.1 % (n = 400) had received ≥ 3 doses. Participants were less likely to be vaccinated than the Australian general population (prevalence ratio: 0.82, 95 % confidence interval [CI]: 0.76-0.88). Key motivations to receive the vaccine were to protect oneself or others from COVID-19, while barriers pertained to vaccine or government distrust. Opioid agonist treatment (adjusted odds ratio [aOR]: 2.49, 95 % CI: 1.44-4.42), current seasonal influenza vaccine uptake (aOR: 6.76, 95 % CI: 3.18-16.75), and stable housing (aOR: 1.58, 95 % CI: 1.02-2.80) were associated with receipt of at least two vaccine doses. Participants aged ≥ 40 years (versus < 40 years; aOR: 1.66, 95 % CI: 1.10-2.53) or who reported a chronic health condition (aOR: 1.71, 95 % CI: 1.18-2.47) had higher odds of receiving at least three vaccine doses. CONCLUSION: We observed higher COVID-19 vaccine uptake than expected given previous studies of vaccine acceptability among people who inject drugs. However, it was lower than the general population. People who inject drugs and reside in unstable housing are a subpopulation that require support to increase vaccine uptake.

Characteristics, toxicology and major organ pathology of deaths due to acute alcohol toxicity in Australia, 2011-2022.

INTRODUCTION: Acute alcohol toxicity is a significant component of alcohol-related mortality. The study aimed to: (i) determine the circumstances of death and characteristics of fatal alcohol toxicity cases, 2011-2022; (ii) determine their toxicological profile and major autopsy findings; and (iii) determine trends in population mortality rates. METHODS: Retrospective study of acute alcohol toxicity deaths in Australia, 2011-2022, retrieved from the National Coronial Information System. RESULTS: A total of 891 cases were identified, with a mean age of 49.2 years, 71.0% being male. Alcohol use problems were noted in 71.3%. In 57.5% death was attributed solely to acute alcohol toxicity, and combined acute alcohol toxicity/disease in 42.5%. There was evidence of sudden collapse in 24.9% of cases. The mean BAC was 0.331 g/100 mL (range 0.107-0.936), and spirits were the most commonly reported beverages (35.8%). Cases of combined toxicity/disease had significantly lower BACs than those attributed solely to alcohol toxicity (0.296 vs. 0.358 g/100 mL). Cardiomegaly was diagnosed in 32.5%, and severe coronary artery disease in 22.1%. Aspiration of vomitus was noted in 18.0%, and chronic obstructive pulmonary disease in 19.6%. Severe liver steatosis was present in 33.4% and 13.6% had cirrhosis. There was an average annual percentage increase in deaths of 7.90. DISCUSSION AND CONCLUSIONS: The 'typical' case was a long-standing, heavy spirits drinker. BACs showed enormous variation and no arbitrary concentration may be deemed lethal. Clinically significant disease was associated with death at a lower BAC and people with such disease may be at increased risk of alcohol poisoning.

Differences in heroin overdose deaths in Australia by age, 2020-2022: Disease and estimated survival times.

Background: The age of people who use illicit opioids has increased, with a clinical picture of accelerated ageing. The study aimed to determine, stratified by age: 1. The circumstances and characteristics of heroin-related toxicity deaths in Australia, 2020-2022; 2. The toxicological profile and autopsy findings; 3. The proportion of cases in which blood 6-acetyl morphine (6AM) was detected, as a measure of survival time. Methods: Retrospective study of 610 cases of fatal heroin-related drug toxicity in Australia, 2020-2022. Cases were stratified as: <30 years, 30-39 years, 40-49 years, ≥50 years. Results: Compared to the youngest group, those aged ≥50 years were more likely to have a history of chronic pain (12.4 v 3.3 %), to have their death attributed to combined drug toxicity/disease (20.1 v 3.3 %), and to have evidence of a sudden collapse (21.3 v 11.1 %). There were no differences in free morphine concentrations or glucuronide concentrations. Compared to the youngest group, however, the two older groups were significantly more likely to have 6AM present in blood, a proxy measure of a shorter survival time (52.0, 55.2 v 34.5 %). Compared to the youngest group, cases aged ≥50 years were more likely to be diagnosed with cardiomegaly (44.0 v 16.7 %), coronary artery disease (46.0 v 15.0 %), emphysema (35.0 v 5.1 %), hepatic steatosis (15.4 v 3.4 %), hepatic fibrosis (17.6 v 3.4 %), and cirrhosis (19.8 v 0.0 %). Conclusions: Older cases of heroin overdose had more extensive heart, lung, and liver disease, and appeared more likely to have shorter survival times.

The relationship between cryptomarket drug purchase, social networks and adverse drug events: A cross-sectional study.

INTRODUCTION: Drug use and trading are typically social activities; however, supply through cryptomarkets can occur without any in-person social contact. People who use drugs alone may be at higher risk of experiencing harms, for example, due to lack of others who may call for emergency assistance. Alternatively, cryptomarkets may be a source of harm reduction information and drugs with better-known content and dose, potentially reducing the risk of adverse events. This study examines relationships between cryptomarket use, drug-using social networks and adverse drug events for MDMA, cocaine and LSD. METHOD: A subsample of 23,053 respondents from over 70 countries was collected in the 2018 Global Drug Survey. People who reported using MDMA, cocaine or LSD were asked about using cryptomarkets to purchase these drugs; any adverse drug events requiring medical treatment (combining seeking treatment and should have sought treatment but did not); and social networks who they had used the specific drug with. All measures referred to the last 12 months, hereon referred to as 'recent'. Binary logistic regressions examined relationships between cryptomarket use, drug-using social networks, and adverse drug events, controlling for age, gender, and frequency of drug use. RESULTS: Adverse events from any drug type were low (5.2%) and for each drug; MDMA (3.5%); cocaine (3.3%); and LSD (3.5%). After controlling for covariates, recent cryptomarket use was associated with increased likelihood of having no drug-using network for each drug type. People who recently used cryptomarkets were more likely to report adverse cocaine (AOR = 1.70 (1.22-2.37)) and LSD (AOR = 1.58 (1.12-2.09)) events. For those reporting a network size >1, network characteristics did not differ with recent cryptomarket use; however, those reporting recent cryptomarket use were more likely to report adverse LSD events (AOR = 1.86 (0.99-3.51)). CONCLUSION: People who reported purchasing drugs from cryptomarkets more commonly reported having no drug-using network, and cryptomarket purchase was associated with reported adverse events. Our results support the notion that cryptomarket use increases drug-related harm, but further disentanglement of multiple complex mechanisms is needed in future research.

A descriptive coronial study of heroin toxicity deaths in Australia, 2020-2022: Characteristics, toxicology and survival times.

BACKGROUND AND AIMS: Mortality rates among people who use heroin are estimated to be 15 times that of the general population. The study aimed to determine (1) the case characteristics and circumstances of death of heroin-related toxicity deaths in Australia, 2020-2022; (2) their toxicological profile and major autopsy findings; (3) the proportion of cases in which blood 6-acetyl morphine (6AM) was detected, as a proxy measure of survival times; and (4) compare 6AM positive and negative cases on toxicology, circumstances of death and acute clinical presentation. DESIGN: Retrospective study of heroin toxicity deaths in Australia, 2020-2022, retrieved from the National Coronial Information System. SETTING: This study was conducted Australia-wide. CASES: There were 610 cases of fatal heroin-related drug toxicity. MEASUREMENTS: Information was collected on characteristics, manner of death, toxicology and autopsy results. FINDINGS: The mean age was 42.6 years (range 18-73 years), 80.5% were male and 7.5% were enrolled in a drug treatment programme. The circumstances of death were as follows: unintentional drug toxicity (86.2%), combined unintentional drug toxicity/disease (11.3%) and intentional drug toxicity (2.5%). The median free morphine concentration was 0.17 mg/L (range 0.00-4.20 mg/L). Psychoactive drugs other than heroin were present in 95.2% (Confidence Interval 93.1%-96.8%), most commonly hypnosedatives (62.3%, 58.2%-66.4%) and psychostimulants (44.8%, 40.7%-49.1%). Major autopsy findings of clinical significance included acute bronchopneumonia (14.8%, 11.3%-18.8%), emphysema (16.9%, 13.2%-21.1%), cardiomegaly (30.1%, 12.7%-28.2%), coronary artery disease (27.4%, 23.0%-32.3%), coronary replacement fibrosis (13.4%, 10.1%-17.3%), hepatic cirrhosis (8.8%, 6.6%-12.2%) and renal fibrosis (10.3%, 7.3%-14.0%). In 47.0% (42.3%-51.2%), 6AM was present in blood. CONCLUSIONS: The 'typical' heroin overdose case in Australia from 2020 to 2022 was a male who injected heroin, aged in the 40s, not enrolled in a treatment programme and had used multiple drugs. In over half of cases, there had been a sufficient survival time for 6-acetyl morphine to have been metabolised, which may indicate times in excess of 20-30 min.

Information acquisition and dissemination among a sample of people who inject drugs in Australia.

INTRODUCTION: This paper examines the acquisition and dissemination of harm reduction information among people who inject drugs, as well as preferred sources of information. METHODS: Data were obtained from 862 people who inject drugs, recruited from Australian capital cities for the 2021 Illicit Drug Reporting System. Multivariable regression analyses were performed to assess potential factors associated with knowledge sharing. RESULTS: Almost two-fifths (37%) reported that they had received information about how to keep themselves safe when using drugs within the past 6 months. Reporting on their last occasion of receiving information, participants stated that it was commonly about injecting practices (56%), overdose prevention (26%) and injection-related injuries (22%), and was mostly received from an alcohol and other drug worker (54%), followed by other health professional (24%) and social network (18%). Among those who reported receiving information, 50% shared this information with other people, predominantly with their social network: no factors were found to be significantly associated with sharing information. The majority reported that peer workers and/or people with lived experience would be the first person they would talk to for information about a range of topics (e.g., injecting/harm reduction practices, overdose prevention). DISCUSSION AND CONCLUSIONS: Two in five participants had recently obtained information about how to keep themselves safe while using drugs, with half sharing this information with their social network. Peer workers were the preferred source of information, suggesting that the peer educator workforce should be expanded to embrace the capacities and expertise of people who inject drugs.

Comparing police use of drug detection dogs amongst injecting and non-injecting groups of people who regularly use drugs in Australia.

INTRODUCTION: Drug detection dogs are utilised across multiple settings, however existing literature focuses predominantly on festival-based encounters. We compare drug dog encounters in non-festival settings among two samples of people who regularly use drugs, and investigate factors associated with witness only versus stop and/or search encounters. METHODS: Australians who regularly (i.e., ≥monthly) use ecstasy and/or other illegal stimulants (n = 777; Ecstasy and Related Drugs Reporting System (EDRS)) or inject illegal drugs (n = 862; Illicit Drugs Reporting System (IDRS)) were surveyed between April-June, 2019. Univariable regression analyses were used to test for differences in drug dog encounters between samples, and to identify factors associated with a more intensive drug dog encounter (namely those that involved a stop and/or search). RESULTS: People who inject drugs were less likely to witness drug dogs than those who regularly use ecstasy and/or other illegal stimulants (odds ratio (OR) 0.46; 95 % CI 0.30-0.69). They were significantly more likely than EDRS participants to report being stopped and searched (3.29; 1.68-6.44) however. Among those carrying drugs at their last stop and/or search encounter, the majority of both samples reported that their drugs were not detected by police. IDRS participants aged 35-49 were more likely to report a stop and/or search encounter than those aged 17-34; no significant associations were found among the EDRS sample. CONCLUSIONS: Despite participants who use ecstasy and/other stimulants being more likely than those who regularly inject drugs to report encountering drug dogs in non-festival settings, participants who inject drugs were more likely to report an intensive or invasive drug dog encounter and/or receiving a formal criminal justice consequence. This study reinforces questions about the efficacy and appropriateness of drug dog operations.

Has there been an increase in nitrous oxide use and associated harms in Australia? An analysis of triangulated data sources, 2003-2020.

BACKGROUND: There is growing concern, globally, regarding use of nitrous oxide (N2O) for intoxication purposes. This paper aims to examine trends in: (i) past six month N2O use among a sample of people who use regularly use ecstasy and/or other illicit stimulants (2003-2020); (ii) volume of N2O-related Google searches and social media posts (2009-2020); and (iii) N2O-related calls to Poisons Information Centres (PIC) (2004-2020). METHODS: Data were obtained from annual interviews with sentinel samples of Australians aged ≥16 years who used ecstasy and/or other illicit stimulants ≥monthly and resided in a capital city (∼800 each year); Google search activity; social media posts; and exposure calls to four PIC. RESULTS: Among samples of people who regularly use ecstasy and/or other illicit stimulants, past six-month N2O use increased 10% each year from 2009 to 2020, with the sharpest increase observed between 2015 and 2018 (25.4% p/year; 95% CI: 14.6-37.1). Frequency and quantity of N2O use remained stable and low. Google search probabilities increased by 1.8% each month from January 2009 and December 2019 (95% CI: 1.5-2.2), with the sharpest increase observed between July 2016 to December 2017 (6.0% p/month; 95% CI: 4.4-7.5). Social media posts increased 2.0% per month from January 2009 and December 2019 (95% CI: 1.1-3.0), with the sharpest increase observed between March and October 2017 (19.2% p/month; 95% CI: 1.7-39.7). The number of N2O-related calls to Australian PIC increased sixfold between 2016 (16) and 2020 (111). CONCLUSIONS: Triangulation of various data sources indicate significant shifts in N2O use and harms in Australia. This includes increases in use, Google searches and social media posts, although these have plateaued in recent years, coupled with increased rates of harm. These findings correspond with evidence of a global increase in N2O use and harm, highlighting the need for education of both people who use N2O and health professionals.

Trends and psychosocial correlates of same day polysubstance use among people who inject drugs in Australia, 2012-2022.

BACKGROUND: Polysubstance use is associated with negative health and social outcomes among people who inject drugs. We aimed to describe trends in polysubstance use and identify psychosocial correlates and associated drug use risk behaviours. We defined polysubstance use as intentional same day use of more than one of three drug classes: opioids, other non-opioid depressants (hereafter 'depressants'), and stimulants. METHODS: We used 10 years (2012-2022, excluding 2020) of data from annual surveys in Australian capital cities with people who inject drugs (N=5657) to construct five mutually exclusive polysubstance use profiles: opioid-depressant, opioid-stimulant, stimulant-depressant, opioid-stimulant-depressant, and single drug class use. We examined time trends using the Mann Kendall test and identified correlates using multinomial logistic regression. RESULTS: Same day polysubstance use was relatively common among this sample (43.6%). Opioid-depressant use was the most frequent polysubstance use profile, but this decreased over the study period (32.6% to 13.3%, p<0.001). This aligned with observed decreases in use of pharmaceutical opioids (p<0.001), opioid agonist treatment (p=0.007), and benzodiazepines (p=0.001). There was no evidence for any trend in the other polysubstance use profiles, although single drug class use increased (51.9% to 64.7%, p=0.031). The different polysubstance use profiles were variously associated with psychosocial factors, including unstable housing and very high psychological distress, and other drug use risk behaviours, including non-fatal overdose, receptive and/or distributive needle sharing, and reusing one's own needles. CONCLUSION: Same day polysubstance use has remained relatively common among this sample over time, although the typology has changed. Collectively, our findings point to diverse drug use patterns among people who inject drugs and reiterate the need for a range of harm reduction, treatment, and support options.

Real or fake? Sourcing and marketing of non-prescribed benzodiazepines amongst two samples of people who regularly use illicit drugs in Australia.

INTRODUCTION: There is concern around non-prescribed benzodiazepine use, particularly with increasing detections of counterfeit products containing high-risk novel compounds. The aims of this study were to investigate how and which non-prescribed benzodiazepines are being sourced; forms, appearance and packaging; and awareness of risks associated with non-prescribed benzodiazepines. METHODS: Data were collected from a sample of Australians who inject drugs or use ecstasy and/or other illicit stimulants on a monthly or more frequent basis, and who reported past 6-month use of non-prescribed benzodiazepines (n = 235 and n = 250, respectively). Data were collected on source, diversion from a known/trusted prescription, product name and aesthetic characteristics for the last non-prescribed benzodiazepine obtained. RESULTS: Amongst participants who injected drugs, 71% reported that their last non-prescribed benzodiazepines were diverted from a known/trusted prescription, compared to 59% of participants who used ecstasy/other stimulants. Sourcing via cryptomarkets was rare. Across both samples, the majority reported last obtaining substances sold/marketed as diazepam or alprazolam. Participants sourcing via non-diverted means were twice as likely to obtain alprazolam. Known sourcing of novel compounds was rare. Amongst participants who used ecstasy/other stimulants, 36% reported confidence in the content/dose of non-prescribed benzodiazepines even when the source is unknown. DISCUSSION AND CONCLUSIONS: Most participants obtained substances sold as classic/registered benzodiazepines, mostly via diverted prescriptions, with a substantial minority potentially unaware of counterfeits circulating. While diverted use undeniably presents risks, tightening of prescriptions in Australia could inadvertently lead to greater supply of novel benzodiazepines as seen internationally, reinforcing prioritisation of demand and harm reduction strategies.

All-cause and cause-specific mortality in individuals with an alcohol-related emergency or hospital inpatient presentation: A retrospective data linkage cohort study.

BACKGROUND AND AIMS: Alcohol consumption is a leading risk factor for premature mortality globally, but there are limited studies of broader cohorts of people presenting with alcohol-related problems outside of alcohol treatment services. We used linked health administrative data to estimate all-cause and cause-specific mortality among individuals who had an alcohol-related hospital inpatient or emergency department presentation. DESIGN: Observational study using data from the Data linkage Alcohol Cohort Study (DACS), a state-wide retrospective cohort of individuals with an alcohol-related hospital inpatient or emergency department presentation. SETTING: Hospital inpatient or emergency department presentation in New South Wales, Australia, between 2005 and 2014. PARTICIPANTS: Participants comprised 188 770 individuals aged 12 and above, 66% males, median age 39 years at index presentation. MEASUREMENTS: All-cause mortality was estimated up to 2015 and cause-specific mortality (by those attributable to alcohol and by specific cause of death groups) up to 2013 due to data availability. Age-specific and age-sex-specific crude mortality rates (CMRs) were estimated, and standardized mortality ratios (SMRs) were calculated using sex and age-specific deaths rates from the NSW population. FINDINGS: There were 188 770 individuals in the cohort (1 079 249 person-years of observation); 27 855 deaths were recorded (14.8% of the cohort), with a CMR of 25.8 [95% confidence interval (CI) = 25.5, 26.1] per 1000 person-years and SMR of 6.2 (95% CI = 5.4, 7.2). Mortality in the cohort was consistently higher than the general population in all adult age groups and in both sexes. The greatest excess mortality was from mental and behavioural disorders due to alcohol use (SMR = 46.7, 95% CI = 41.4, 52.7), liver cirrhosis (SMR = 39.0, 95% CI = 35.5, 42.9), viral hepatitis (SMR = 29.4, 95% CI = 24.6, 35.2), pancreatic diseases (SMR = 23.8, 95% CI = 17.9, 31.5) and liver cancer (SMR = 18.3, 95% CI = 14.8, 22.5). There were distinct differences between the sexes in causes of excess mortality (all causes fully attributable to alcohol female versus male risk ratio = 2.5 (95% CI = 2.0, 3.1). CONCLUSIONS: In New South Wales, Australia, people who came in contact with an emergency department or hospital for an alcohol-related presentation between 2005 and 2014 were at higher risk of mortality than the general New South Wales population during the same period.

Agreement between self-reported illicit drug use and biological samples: a systematic review and meta-analysis.

BACKGROUND AND AIMS: Studies often rely upon self-report and biological testing methods for measuring illicit drug use, although evidence for their agreement is limited to specific populations and self-report instruments. We aimed to examine comprehensively the evidence for agreement between self-reported and biologically measured illicit drug use among all major illicit drug classes, biological indicators, populations and settings. METHODS: We systematically searched peer-reviewed databases (Medline, Embase and PsycINFO) and grey literature. Included studies reported 2 × 2 table counts or agreement estimates comparing self-reported and biologically measured use published up to March 2022. With biological results considered to be the reference standard and use of random-effect regression models, we evaluated pooled estimates for overall agreement (primary outcome), sensitivity, specificity, false omission rates (proportion reporting no use that test positive) and false discovery rates (proportion reporting use that test negative) by drug class, potential consequences attached to self-report (i.e. work, legal or treatment impacts) and time-frame of use. Heterogeneity was assessed by inspecting forest plots. RESULTS: From 7924 studies, we extracted data from 207 eligible studies. Overall agreement ranged from good to excellent (> 0.79). False omission rates were generally low, while false discovery rates varied by setting. Specificity was generally high but sensitivity varied by drug, sample type and setting. Self-report in clinical trials and situations of no consequences was generally reliable. For urine, recent (i.e. past 1-4 days) self-report produced lower sensitivity and false discovery rates than past month. Agreement was higher in studies that informed participants biological testing would occur (diagnostic odds ratio = 2.91, 95% confidence interval = 1.25-6.78). The main source of bias was biological assessments (51% studies). CONCLUSIONS: While there are limitations associated with self-report and biological testing to measure illicit drug use, overall agreement between the two methods is high, suggesting both provide good measures of illicit drug use. Recommended methods of biological testing are more likely to provide reliable measures of recent use if there are problems with self-disclosure.

Characteristics and circumstances of volatile solvent misuse-related death in Australia, 2000-2021.

INTRODUCTION: Volatile solvent misuse-related death is associated with neuropsychiatric, cardiovascular, respiratory and renal pathology, as well as sudden death. The study aimed to determine: (1) the circumstances of death and case characteristics of volatile solvent misuse-related death in Australia, 2000-2021; (2) the toxicological profile of cases; and (3) the major autopsy findings. METHODS: Retrospective study of volatile solvent misuse-related death in Australia, 2000-2021 retrieved from the National Coronial Information System. FINDINGS: One hundred and sixty-four cases were identified, 79.9% male, mean age 26.5 years (8.5% aged 40 years or older). Circumstances of death were unintentional toxicity (61.0%), unintentional asphyxia (20.1%), intentional self-harm (12.2%) and traumatic accident (6.7%). The most commonly reported acute presentation prior to death was sudden collapse (22 of 47 witnessed events). The most frequently used solvents at the fatal incident were gas fuels (35.4%), gasoline (petrol) (19.5%) adhesives/paints (19.5%), aerosol propellants (12.8%), and volatile anaesthetics (12.8%). The most commonly detected volatile substances were butane (40.7%), toluene (29.6%), and propane (25.9%). Cannabis was present in 27.6% and alcohol in 24.6%. The prevalence of acute pneumonia amongst autopsied cases was low (5.8%) which, together with reports of sudden collapse, suggests that in many cases, death was extremely rapid. There were low levels of major organ pathology. CONCLUSIONS: While the average age of volatile solvent misuse-related death was in the mid-twenties, a substantial proportion occurred amongst people aged 40 years or older. Reflecting availability, gas fuels predominated. In many cases, death appeared to have been rapid.

Epidemiology of injecting drug use, prevalence of injecting-related harm, and exposure to behavioural and environmental risks among people who inject drugs: a systematic review.

BACKGROUND: People who inject drugs are exposed to various and changing risk environments and are at risk of multiple harms related to injecting drug use (IDU). We aimed to undertake a global systematic review of the prevalence of IDU, key IDU-related harms (including HIV, hepatitis C virus [HCV], and hepatitis B virus [HBV] infection and overdose), and key sociodemographic characteristics and risk exposures for people who inject drugs. METHODS: We systematically searched for data published between Jan 1, 2017, and March 31, 2022, in databases of peer-reviewed literature (MEDLINE, Embase, and PsycINFO) and grey literature as well as various agency or organisational websites, and disseminated data requests to international experts and agencies. We searched for data on the prevalence, characteristics, and risks of people who inject drugs, including gender, age, sexuality, drug-use patterns, HIV, HCV, and HBV infections, non-fatal overdose, depression, anxiety, and injecting-related disease. Additional data were extracted from studies identified in our previous review. Meta-analyses were used to pool the data where multiple estimates were available for a country. We present country, regional, and global estimates for each variable examined. FINDINGS: We screened 40 427 reports published between 2017 and 2022, and the 871 eligible reports identified were added to the 1147 documents from the previous review. Evidence of IDU was documented in 190 of 207 countries and territories, and 14·8 million people (95% uncertainty interval [UI] 10·0-21·7) aged 15-64 years globally were estimated to inject drugs. Existing evidence suggests that there might be 2·8 million (95% UI 2·4-3·2) women and 12·1 million (95% UI 11·0-13·3) men who inject drugs globally, and that 0·4% (95% CI 0·3-1·3) of people who inject drugs identify as transgender. The amount of available data on key health and social risks among people who inject drugs varied widely across countries and regions. We estimated that 24·8% (95% CI 19·5-31·6) of people who inject drugs globally had experienced recent homelessness or unstable housing, 58·4% (95% CI 52·0-64·8) had a lifetime history of incarceration, and 14·9% (95% CI 8·1-24·3) had recently engaged in sex work, with substantial geographical variation. Injecting and sexual risk behaviour varied considerably geographically, as did risks of harms. Globally, we estimated that 15·2% (95% CI 10·3-20·9) of people who inject drugs are living with HIV, 38·8% (95% CI 31·4-46·9) have current HCV infection, 18·5% (95% CI 13·9-24·1) have recently overdosed, and 31·7% (95% CI 23·6-40·5) have had a recent skin or soft tissue infection. INTERPRETATION: IDU is being identified in a growing number of countries and territories that comprise more than 99% of the global population. IDU-related health harms are common, and people who inject drugs continue to be exposed to multiple adverse risk environments. However, quantification of many of these exposure and harms is inadequate and must be improved to allow for better targeting of harm-reduction interventions for these risks. FUNDING: Australian National Health and Medical Research Council.

Global coverage of interventions to prevent and manage drug-related harms among people who inject drugs: a systematic review.

BACKGROUND: Harm reduction and treatment programmes are essential for reducing harms for people who inject drugs (PWID). We aimed to update estimates from a 2017 review of global coverage of needle and syringe exchange programmes (NSPs), opioid agonist treatment (OAT), and other harm reduction services that target PWID (eg, take-home naloxone [THN] programmes, supervised consumption facilities, and drug checking services). METHODS: We did a systematic review of available evidence from peer-reviewed and grey literature databases for studies published between Jan 1, 2017, and May 31, 2022. Programmatic data were collected on the availability of services, the number of sites, people accessing services, and equipment distributed in countries where there is evidence of injecting drug use. National estimates of coverage of OAT (ie, number of people accessing OAT per 100 PWID) and NSPs (ie, number of needles and syringes distributed per PWID per year) were generated where available using the most recent data. Regional and global estimates were derived and compared with WHO indicators. The study was registered with PROSPERO (CRD42020173974). FINDINGS: We included 195 studies and found there were 90 countries implementing OAT (75% of the PWID population) and 94 countries implementing NSPs (88% of the global PWID population). Only five countries (2% of the global PWID population) are providing high coverage of both services. Far fewer countries were implementing THN programmes (n=43), supervised consumption facilities (n=17), and drug checking services (n=26), with nine countries implementing all five services. Globally, we estimated there were 18 (95% uncertainty interval [UI] 12-27) people accessing OAT per 100 PWID, and 35 (95% UI 24-52) needles and syringes being distributed per person who injects drugs per year. More countries reported high (OAT 24; NSPs 10), moderate (OAT 8; NSPs 15), and low (OAT 38; NSPs 47) coverage of services compared with the previous review. INTERPRETATION: Global coverage of OAT and NSPs has increased modestly in the past 5 years but remains low for most countries. Programmatic data on other key harm reduction interventions are scarce. FUNDING: Australian National Health and Medical Research Council.