Psychosocial factors associated with overdose subsequent to Illicit Drug use: a systematic review and narrative synthesis

BACKGROUND AND AIMS

Psychological and social status, and environmental context, may mediate the likelihood of experiencing overdose subsequent to illicit drug use. The aim of this systematic review was to identify and synthesise psychosocial factors associated with overdose among people who use drugs.

METHODS

This review was registered on Prospero (CRD42021242495). Systematic record searches were undertaken in databases of peer-reviewed literature (Medline, Embase, PsycINFO, and Cinahl) and grey literature sources (Google Scholar) for work published up to and including 14 February 2023. Reference lists of selected full-text papers were searched for additional records. Studies were eligible if they included people who use drugs with a focus on relationships between psychosocial factors and overdose subsequent to illicit drug use. Results were tabulated and narratively synthesised.

RESULTS

Twenty-six studies were included in the review, with 150,625 participants: of those 3,383-4072 (3%) experienced overdose. Twenty-one (81%) studies were conducted in North America and 23 (89%) reported polydrug use. Psychosocial factors associated with risk of overdose (n = 103) were identified and thematically organised into ten groups. These were: income; housing instability; incarceration; traumatic experiences; overdose risk perception and past experience; healthcare experiences; perception of own drug use and injecting skills; injecting setting; conditions with physical environment; and social network traits.

CONCLUSIONS

Global rates of overdose continue to increase, and many guidelines recommend psychosocial interventions for dependent drug use. The factors identified here provide useful targets for practitioners to focus on at the individual level, but many identified will require wider policy changes to affect positive change. Future research should seek to develop and trial interventions targeting factors identified, whilst advocacy for key policy reforms to reduce harm must continue.

A multicomponent holistic care pathway for people who use drugs in Tayside, Scotland

BACKGROUND

People Who Use Drugs (PWUD) are at high risk of non-fatal overdose and other drug-related harms. The United Kingdom drugs policy landscape makes it challenging to support those at risk. Tayside, in East Scotland, has a sizeable population at risk of drug-related harms. In 2021, the National Health Service implemented a care pathway for PWUD to provide multidimensional healthcare interventions. We aimed to quantify drug-related harms; assess wider health and well-being; and understand substance use trends and behaviours, among those engaged in the pathway.

METHODS

Existing community-embedded blood-borne virus pathways were adapted to provide multiple healthcare assessments over three visits. We undertook an observational cohort study to analyse uptake and outcomes for the initial cohort of PWUD engaged at appointment one.

RESULTS

From August 2021-September 2022, 150 PWUD engaged with the pathway. Median age was 39 (34-42) years, 108 (72%) were male, and 124 (83%) lived in deprived areas. Seventy (47%) had been disengaged from healthcare for over a year. Polysubstance use was reported by 124 (83%), 42 (28%) disclosed injecting daily, and 54 (36%) shared equipment. Fifty-four (36%) experienced recent non-fatal overdose, and there were six overdose fatalities (4.1 [1.5-9.0] per 100PY). The offer of take-home naloxone was accepted by 108 (72%). Fourteen (9%) were diagnosed with Hepatitis C and two (1%) with HIV. Renal, hepatological, and endocrine impairment were observed among 30 (20%), 23 (15%), and 11 (7%), people respectively. Ninety-six (65%) had high risk of clinical depression. Forty-eight (32%) declined Covid-19 vaccination.

CONCLUSION

The pathway engaged PWUD with high exposure to recent non-fatal overdose and other drug-related harms, alongside co-morbid health issues. Our results suggest multi-dimensional health assessments coupled with harm reduction in community settings, with appropriate linkage to care, are warranted for PWUD. Service commissioners should seek to integrate these assessments where possible.

Evaluation of the scale-up of HIV testing among people who inject drugs in Scotland in the context of an ongoing HIV outbreak

BACKGROUND

A large outbreak of HIV among people who inject drugs (PWID) has been ongoing in Glasgow city centre (GCC), Scotland since early 2015. The outbreak is associated with high levels of homelessness, cocaine injecting and injecting in public places. A key component of the public health response was the scale-up of HIV testing in a range of services engaged with PWID. Our aims were to: 1) evaluate the extent of and change in HIV testing over the course of the outbreak and 2) examine factors associated with reporting an HIV test.

METHODS

Self-report of an HIV test in the last 12 months was collected for 15,081 PWID interviewed in six national cross-sectional bio-behavioural surveys during 2008-2018. Multi-variate logistic regression was undertaken to determine trends in HIV testing by region of recruitment (GCC; rest of Glasgow; other Scottish city centres (SCC); and rest of Scotland) and outbreak period (pre: 2008-14; early: 2015-16; ongoing: 2017-18).

RESULTS

HIV testing increased across all regions and was most pronounced in GCC comparing the ongoing (67%) to the pre-outbreak period (33%) (aOR=4.68, 95% CI 3.23 to 6.77, p<0.001). However, compared to other SCCs pre-outbreak (with 46% reporting testing), those recruited in GCC had a lower odds of HIV testing early outbreak (aOR=0.37, 95% CI 0.27 to 0.54, p<0.001) and more modest increased odds in the ongoing outbreak period (aOR=1.41, 95% CI 0.97 to 2.05, p=0.069). Among PWID recruited in the whole of Glasgow in the ongoing phase, reporting an HIV test was associated with injecting cocaine or in public places (aOR=2.20, 95% CI 1.53 to 3.17, p<0.001), receipt of methadone (aOR=1.48, 95% CI 1.01 to 2.17, p=0.042) and incarceration in the last year (aOR=1.72, 95% CI 1.18 to 2.51, p=0.004).

CONCLUSIONS

Relatively low levels of HIV testing pre- and early-outbreak likely hindered efforts to control the spread of infection among PWID in Glasgow. Uptake has since increased with expansion of testing across multiple settings, particularly among those at high risk of infection. Further effort is needed to ensure the vast majority of PWID are regularly tested, not just in the epicentre of the outbreak but in other areas with low population prevalence of infection.

High response and re-infection rates among people who inject drugs treated for hepatitis C in a community needle and syringe programme

To achieve WHO hepatitis C virus (HCV) elimination targets by 2030, mathematical models suggest there needs to be significant scale-up of treatment among people who inject drugs (PWID). We tested whether people who actively inject drugs can be recruited and treated successfully through a community needle and syringe programme (NSP), and assessed rates of re-infection. 105 HCV RNA positive participants were enrolled prospectively. Participants were recruited from the largest NSP in Dundee over 42 months. 94/105 individuals commenced treatment. Genotype 1 (G1) individuals (n = 37) were treated with peg-interferon+ribavirin+Simepravir/Telaprevir. Genotype 2/3 (G2/3) (n = 57) received peg-interferon+ribavirin. Weekly study visits took place within the NSP. Mean age of participants was 34.0 years (SD 6.9), 71.3% (61/94) were male. One in five (20/94) participants were homeless. 68.1% (64/94) were on OST (opiate substitution therapy) at enrolment; participants injected median 6.5 times/wk. In terms of clinical outcomes, >80% treatment adherence was 71.3% (67/94). There was no difference in SVR-12 rates by genotype: 81.0% (30/37) for G1 and 82.5% (47/55) for G2/3. At 18 months post-treatment, 15/77 participants were reinfected, followed up over 69.8 person-years, yielding a re-infection rate of 21.5/100 person-years (95% CI 13.00-35.65). This trial demonstrates that HCV treatment can be delivered successfully to the target population of treatment as prevention strategies. We report higher rates of re-infection than existing estimates among PWID. Scale-up of HCV treatment should be pursued alongside a comprehensive programme of harm reduction interventions to help minimize re-infection and reduce HCV transmission.

The value of DNA paternity identification in beef cattle: Examples from Nevada's free-range ranches1

The feasibility and economic value of DNA paternity identification were investigated and illustrated using Nevada beef cattle operations. A panel of 15 microsatellites was genotyped in 2,196 animals from 8 ranches with a total of 31,571 genotypes. Probabilities of exclusion for each marker within ranch and across ranches were computed. Joint probabilities of exclusion for the 15 microsatellites were also determined, resulting in values over 0.99 for any individual ranch and across ranches. Dropping 1 or 2 microsatellites with the lowest probabilities of exclusion resulted in joint probabilities greater than 0.99 and with marginal reduction compared with the probabilities with 15 microsatellites. Formulas for benefit-cost analysis for a DNA paternity identification program in beef cattle were derived. Genotyping 15 microsatellites with 20 calves per sire resulted in benefits of $1.71 and $2.44 per dollar invested at bull culling rates of 0.20 and 0.30, respectively. The breakpoints for the program to be profitable occurred when the ratio of the price of 1 kg of calf liveweight over the cost of genotyping 1 microsatellite was greater than 1.1 for a bull culling rate of 0.30. Benefit-cost analysis was also derived under incomplete DNA paternity identification using a lower number of DNA markers than necessary to achieve joint probabilities of exclusion of 0.99. Approximately a 20% increase in the benefit-cost ratio was achieved using 10 vs. 12 microsatellites with incomplete paternity identification. The greater the number of bulls in the operation, the lower the benefit-cost ratio of the paternity testing program. Low probabilities of exclusion and a high number of bulls in the beef operation reduced the benefit-cost ratio dramatically. The DNA paternity identification programs are feasible and may be profitable for free-range beef cattle operations.