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.

Global, regional, and country-level coverage of testing and treatment for HIV and hepatitis C infection among people who inject drugs: a systematic review.

BACKGROUND: People who inject drugs are disproportionately affected by HIV and hepatitis C virus (HCV) infections, while there is little global data on HIV and HCV testing and treatment coverage of this population. We conducted a systematic review to evaluate country-level, regional, and global coverage of HIV and HCV testing and treatment among people who inject drugs. METHODS: We did a systematic review, and searched bibliographic databases (MEDLINE, Embase, and PsycINFO) and grey literature for studies published between Jan 1, 2017, and April 30, 2022, that evaluated the proportion of people who inject drugs who received testing or treatment for HIV or HCV. For each country, we estimated the proportion of people who inject drugs tested for HIV antibodies in the past 12 months (recent), people who inject drugs ever tested for HCV antibodies and HCV RNA, people who inject drugs with HIV currently receiving antiretroviral therapy, and people who inject drugs with HCV ever receiving HCV antiviral treatment. Regional and global estimates, weighted by the population size of people who inject drugs, were generated where sufficient data were available. This study is registered with PROSPERO (CRD42020173974). FINDINGS: 512 documents reported data eligible for analyses, including 337 peer-reviewed articles, 27 conference abstracts or presentations, and 148 documents from grey literature or supplementary searches. Data of recent HIV antibody testing were available for 67 countries and ever having had HCV antibody testing were available for 49 countries. Globally, an estimated 48·8% of people who inject drugs were recently tested for HIV antibodies (95% uncertainty interval [UI] 43·3-54·2%; range 0·9-86·0%), and 47·1% had ever been tested for HCV antibodies (95% UI 43·4-51·0%; range 0·0-93·3%). HCV RNA testing data were available from three countries. Coverage of HIV antibody testing was high (>75%) in four countries and for HCV antibody testing in 15 countries. The estimated uptake of current HIV treatment (18 countries) ranged from 2·6% to 81·9%, and the estimated uptake of ever having HCV treatment (23 countries) ranged from 1·8% to 88·6% across countries. Uptake of HIV treatment was high in two countries, and of HCV treatment in one country. INTERPRETATION: HIV and HCV testing and treatment uptake among people who inject drugs was highly variable, and suboptimal in most countries. Strategies to improve access to HIV and HCV care among people who inject drugs and the availability of public health surveillance are urgently required. FUNDING: Australian National Health and Medical Research Council and UK National Institute for Health and Care Research Health Protection Research Unit in Behavioural Science and Evaluation.

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.