Recent increases in crack injection and associated risk factors among people who inject psychoactive drugs in England and Wales.

BACKGROUND: Crack use is higher in the United Kingdom (UK) than other European countries. Crack is a stimulant with a short half-life, requiring frequent injection to maintain its euphoric effects, thus increasing the risk of blood borne viruses (BBVs) and skin and soft tissue infections (SSTIs). We assessed trends in the prevalence of current crack injection among people who inject drugs (PWID) and investigated harms and other factors associated with its use. METHODS: We used data from the annual Unlinked Anonymous Monitoring Survey of PWID, which recruits people who have ever injected psychoactive drugs through specialist services. Participants provide a biological sample and self-complete a questionnaire. We included participants from England and Wales who had injected in the past month. We examined trends in crack injection over time (2011-2021) and factors associated with crack injection using multivariable logistic regression (2019-2021). RESULTS: The proportion of people self-reporting crack injection in the past month almost doubled between 2011-2020/21, from 34 % (416/1237) to 57 % (483/850). Crack injection was more frequently reported by males than females (adjusted odds ratio 1.46, 95 % confidence interval: 1.15-1.87) and injected alongside heroin (6.67, 4.06-10.97) more frequently than alone. Crack injection was independently associated with injecting equipment sharing (1.64, 1.30-2.07), groin injection (2.03, 1.60-2.56) in the past month, overdosing in the past year (1.90, 1.42-2.53), homelessness in the past year (1.42, 1.14-1.77) and ever having hepatitis C infection (1.64, 1.31-2.06). CONCLUSION: Crack injection has increased significantly over the past decade in England and Wales. People injecting crack are more likely to engage in behaviours that increase the risk of BBV and SSTI acquisition, such as needle/syringe sharing, groin injection and polydrug use. Harm reduction and drug treatment services should adapt to support the needs of this growing population of people injecting stimulants.

Incidence of HIV and hepatitis C virus among people who inject drugs, and associations with age and sex or gender: a global systematic review and meta-analysis.

BACKGROUND: Measuring the incidence of HIV and hepatitis C virus (HCV) infection among people who inject drugs (PWID) is key to track progress towards elimination. We aimed to summarise global data on HIV and primary HCV incidence among PWID and associations with age and sex or gender. METHODS: In this systematic review and meta-analysis, we updated an existing database of HIV and HCV incidence studies among PWID by searching MEDLINE, Embase, and PsycINFO, capturing studies published between Jan 1, 2000, and Dec 12, 2022, with no language or study design restrictions. We contacted authors of identified studies for unpublished or updated data. We included studies that estimated incidence by longitudinally re-testing people at risk of infection or by using assays for recent infection. We pooled incidence and relative risk (RR; young [generally defined as ≤25 years] vs older PWID; women vs men) estimates using random-effects meta-analysis and assessed risk of bias with a modified Newcastle-Ottawa scale. This study is registered with PROSPERO, CRD42020220884. FINDINGS: Our updated search identified 9493 publications, of which 211 were eligible for full-text review. An additional 377 full-text records from our existing database and five records identified through cross-referencing were assessed. Including 28 unpublished records, 125 records met the inclusion criteria. We identified 64 estimates of HIV incidence (30 from high-income countries [HICs] and 34 from low-income or middle-income countries [LMICs]) and 66 estimates of HCV incidence (52 from HICs and 14 from LMICs). 41 (64%) of 64 HIV and 42 (64%) of 66 HCV estimates were from single cities rather than being multi-city or nationwide. Estimates were measured over 1987-2021 for HIV and 1992-2021 for HCV. Pooled HIV incidence was 1·7 per 100 person-years (95% CI 1·3-2·3; I2=98·4%) and pooled HCV incidence was 12·1 per 100 person-years (10·0-14·6; I2=97·2%). Young PWID had a greater risk of HIV (RR 1·5, 95% CI 1·2-1·8; I2=66·9%) and HCV (1·5, 1·3-1·8; I2=70·6%) acquisition than older PWID. Women had a greater risk of HIV (RR 1·4, 95% CI 1·1-1·6; I2=55·3%) and HCV (1·2, 1·1-1·3; I2=43·3%) acquisition than men. For both HIV and HCV, the median risk-of-bias score was 6 (IQR 6-7), indicating moderate risk. INTERPRETATION: Although sparse, available HIV and HCV incidence estimates offer insights into global levels of HIV and HCV transmission among PWID. Intensified efforts are needed to keep track of the HIV and HCV epidemics among PWID and to expand access to age-appropriate and gender-appropriate prevention services that serve young PWID and women who inject drugs. FUNDING: Canadian Institutes of Health Research, Fonds de recherche du Québec-Santé, Canadian Network on Hepatitis C, UK National Institute for Health and Care Research, and WHO.

Opioid Injection-Associated Bacterial Infections in England, 2002-2021: A Time Series Analysis of Seasonal Variation and the Impact of Coronavirus Disease 2019.

BACKGROUND: Bacterial infections cause substantial pain and disability among people who inject drugs. We described time trends in hospital admissions for injecting-related infections in England. METHODS: We analyzed hospital admissions in England between January 2002 and December 2021. We included patients with infections commonly caused by drug injection, including cutaneous abscesses, cellulitis, endocarditis, or osteomyelitis, and a diagnosis of opioid use disorder. We used Poisson regression to estimate seasonal variation and changes associated with coronavirus disease 2019 (COVID-19) response. RESULTS: There were 92 303 hospital admissions for injection-associated infections between 2002 and 2021. Eighty-seven percent were skin, soft-tissue, or vascular infections; 72% of patients were male; and the median age increased from 31 years in 2002 to 42 years in 2021. The rate of admissions reduced from 13.97 per day (95% confidence interval [CI], 13.59-14.36) in 2003 to 8.94 (95% CI, 8.64-9.25) in 2011, then increased to 18.91 (95% CI, 18.46-19.36) in 2019. At the introduction of COVID-19 response in March 2020, the rate of injection-associated infections reduced by 35.3% (95% CI, 32.1-38.4). Injection-associated infections were also seasonal; the rate was 1.21 (95% CI, 1.18-1.24) times higher in July than in February. CONCLUSIONS: This incidence of opioid injection-associated infections varies within years and reduced following COVID-19 response measures. This suggests that social and structural factors such as housing and the degree of social mixing may contribute to the risk of infection, supporting investment in improved social conditions for this population as a means to reduce the burden of injecting-related infections.

Investigating the sociodemographic and behavioural factors associated with hepatitis C virus testing amongst people who inject drugs in England, Wales and Northern Ireland: A quantitative cross-sectional analysis.

BACKGROUND: Hepatitis C virus (HCV) transmission in the UK is driven by injecting drug use. We explore HCV testing uptake amongst people who inject drugs (PWID) in England, Wales and Northern Ireland, and identify factors associated with i) ever having an HCV test amongst people who have ever injected drugs, and ii) recently having an HCV test (within the current or previous year) amongst people who currently inject drugs (reported injecting drugs within the last year). METHODS: We analysed data from the 2019 'Unlinked Anonymous Monitoring Survey' of PWID, using logistic regression. RESULTS: Of 3,127 PWID, 2,065 reported injecting drugs within the last year. Most (86.7%) PWID had a lifetime history of HCV testing. In multivariable analysis, higher odds of ever testing were associated with: female sex (aOR=1.54; 95%CI 1.11-2.14), injecting duration ≥3 years (aOR=2.94; 95%CI 2.13-4.05), ever receiving used needles/syringes (aOR=1.74; 95%CI 1.29-2.36), ever being on opioid agonist treatment (aOR=2.91; 95%CI 2.01-4.21), ever being imprisoned (aOR=1.86; 95%CI 1.40-2.48) and ever being homeless (aOR=1.54; 95%CI 1.14-2.07). Amongst PWID who had injected drugs within the last year, 49.9% had recently undertaken an HCV test. After adjustment, factors associated with higher odds of undertaking a recent HCV test included: injecting crack in the last year (aOR=1.29; 95%CI 1.03-1.61), experiencing a non-fatal overdose in the last year (aOR=1.39; 95%CI 1.05-1.85), ever being on opioid agonist treatment (aOR=1.48; 95%CI 0.97-2.25), receiving HCV information in the last year (aOR=1.99; 95%CI 1.49-2.65) and using a healthcare service in the last year (aOR=1.80; 95%CI 1.21-2.67). CONCLUSION: Results suggest that PWID who have experienced homelessness and incarceration - amongst the most vulnerable and marginalised in the PWID population - are engaging with HCV testing, but overall there remain missed testing opportunities. Recent initiates to injecting have highest HCV infection risk but lower odds of testing, and peer-education may help target this group.

The characteristics of people who inject drugs in the United Kingdom: changes in age, duration, and incidence of injecting, 1980-2019, using evidence from repeated cross-sectional surveys.

BACKGROUND AND AIMS: Mortality and drug treatment data suggest that the median age of people who inject drugs is increasing. We aimed to describe changes in the characteristics of people injecting drugs in the United Kingdom (UK). DESIGN: Repeat cross-sectional surveys and modelling. SETTING: Low-threshold services in the United Kingdom such as needle and syringe programmes. PARTICIPANTS: A total of 79 900 people who recently injected psychoactive drugs in the United Kingdom, recruited as part of the Unlinked Anonymous Monitoring Survey (England, Wales, Northern Ireland, 1990-2019) and Needle Exchange Surveillance Initiative (Scotland, 2008-2019). MEASUREMENTS: Age of people currently injecting, age at first injection, duration of injecting (each 1990-2019) and estimates of new people who started injecting (1980-2019). FINDINGS: In England, Wales and Northern Ireland between 1990 and 2019, the median age of people injecting increased from 27 (interquartile range [IQR], 24-31) to 40 (IQR, 34-46); median age at first injection increased from 22 (IQR, 19-25) to 33 (IQR, 28-39); and median years of injecting increased from 7 (IQR, 3-11) to 18 (IQR, 9-23). Values in Scotland and England were similar after 2008. The estimated number that started injecting annually in England increased from 5470 (95% prediction interval [PrI] 3120-6940) in 1980 to a peak of 10 270 (95% PrI, 8980-12 780) in 1998, and then decreased to 2420 (95% PrI, 1320-5580) in 2019. The number in Scotland followed a similar pattern, increasing from 1220 (95% PrI, 740-2430) in 1980 to a peak of 3080 (95% PrI, 2160-3350) in 1998, then decreased to a 270 (95% PrI, 130-600) in 2018. The timing of the peak differed between regions, with earlier peaks in London and the North West of England. CONCLUSIONS: In the United Kingdom, large cohorts started injecting psychoactive drugs in the 1980s and 1990s and many still inject today. Relatively few people started in more recent years. This has led to changes in the population injecting drugs, including an older average age and longer injecting histories.

Epidemiology of HIV infection and associated behaviours among people who inject drugs in England, Wales, and Northern Ireland: Nearly 40 years on.

INTRODUCTION: People who inject drugs are at high risk of blood-borne infections. We describe the epidemiology of HIV among people who inject drugs in England, Wales, and Northern Ireland (EW&NI) since 1981. METHODS: National HIV surveillance data were used to describe trends in diagnoses (1981-2019), prevalence (1990-2019), and behaviours (1990-2019) among people who inject drugs aged ≥15 years in EW&NI. HIV care and treatment uptake were assessed among those attending in 2019. RESULTS: Over the past four decades, the prevalence of HIV among people who inject drugs in EW&NI remained low (range: 0.64%-1.81%). Overall, 4978 people who inject drugs were diagnosed with HIV (3.2% of cases). Diagnoses peaked at 234 in 1987, decreasing to 78 in 2019; the majority were among white men born in the UK/Europe (90%), though the epidemic diversified over time. Late diagnosis (CD4 <350 cells/µl) was common (2010-2019: 52% [429/832]). Of those who last attended for HIV care in 2019, 97% (1503/1550) were receiving HIV treatment and 90% (1375/1520) had a suppressed viral load (<200 copies/ml). HIV testing uptake has steadily increased among people who inject drugs (32% since 1990). However, in 2019, 18% (246/1404) of those currently injecting reported never testing. The proportion of people currently injecting reporting sharing needles/syringes decreased from 1999 to 2012, before increasing to 20% (288/1426) in 2019, with sharing of any injecting equipment at 37% (523/1429). CONCLUSION: The HIV epidemic among people who inject drugs in EW&NI has remained relatively contained compared with in other countries, most likely because of the prompt implementation of an effective national harm reduction programme. However, risk behaviours and varied access to preventive interventions among people who inject drugs indicate the potential for HIV outbreaks.

The Effectiveness of Low Dead Space Syringes for Reducing the Risk of Hepatitis C Virus Acquisition Among People Who Inject Drugs: Findings From a National Survey in England, Wales, and Northern Ireland.

Syringes with attached needles (termed fixed low dead space syringes [LDSS]) retain less blood following injection than syringes with detachable needles, but evidence on them reducing blood-borne virus transmission among people who inject drugs (PWID) is lacking. Utilizing the UK Unlinked Anonymous Monitoring cross-sectional bio-behavioral surveys among PWID for 2016/18/19 (n = 1429), we showed that always using fixed LDSS was associated with 76% lower likelihood (adjusted odds ratio  = 0.24, 95% confidence interval [CI]: .08-.67) of recent hepatitis C virus infection (RNA-positive and antibody-negative) among antibody-negative PWID compared to using any syringes with detachable needles.

Perceived availability and carriage of take-home naloxone and factors associated with carriage among people who inject drugs in England, Wales and Northern Ireland.

BACKGROUND: In 2019-2020, record-high numbers of overdoses have been reported across the UK. We estimated perceived availability to and carriage of naloxone and explored factors associated with carriage among people who inject drugs (PWID) engaged with services in England, Wales, and Northern Ireland. METHODS: Participants were PWID enrolled in the Unlinked Anonymous Monitoring Survey in 2019 who reported past-year injection drug use (n = 2,139). Recruitment occurred through specialist and community drug agencies located across the UK, excluding Scotland. Socio-demographic, behavioural and service use characteristics were self-reported. Participants were asked whether they carry naloxone (timeframe unspecified). If they answered "no", they were further asked whether it is available in their area. Perceived naloxone availability and carriage were estimated by requirement region, classified using the Nomenclature of Territorial Units for Statistics 1. We used the Gelberg-Andersen Model of healthcare access to explore predisposing, enabling and need factors associated with regionally-aggregated naloxone carriage. RESULTS: Perceived naloxone availability was ≥95% in all 11 regions; naloxone carriage varied (mean: 61.1; range: 48%-71%; P<0.01). Among predisposing factors, female gender (adjusted odds ratio (AOR): 1.52; 95% confidence interval (CI): 1.21-1.91) was positively associated with naloxone carriage, whilst recruitment in Yorkshire and the Humber-relative to London-was negatively associated (AOR: 0.55; 95%CI: 0.37-0.82). Among enabling factors, past-year contact with needle and syringe programmes (AOR: 1.74; 95%CI: 1.39-2.18) and currently receiving treatment for drug use (AOR: 1.75; 95%CI: 1.24-2.46) were positively associated with naloxone carriage. Among need characteristics, past-month heroin injection, with or without past-month high-risk drinking or benzodiazepine use, was positively associated with carriage relative to no heroin injection (range of AORs: 1.71-2.58). CONCLUSION: Perceived naloxone availability is very high among PWID attending services in England, Wales, and Northern Ireland. Naloxone carriage is moderately high and varying across regions, and appears improved through recent engagement with harm-reduction programs.