High risk injecting behaviour among people who inject pharmaceutical opioids in Australia

Epidemiology of acute infections in people who inject drugs in Australia

ISSUES

People who inject drugs are at risk of acute infections, such as skin and soft tissue infections, infective endocarditis, bone and joint infections and bloodstream infections. There has been an increase in these infections in people who inject drugs internationally over the past 10 years. However, the local data regarding acute infections in Australia has not been well described.

APPROACH

We review the epidemiology of acute infections and associated morbidity and mortality amongst people who inject drugs in Australia. We summarise risk factors for these infections, including the concurrent social and psychological determinants of health.

KEY FINDINGS

The proportion of people who report having injected drugs in the prior 12 months in Australia has decreased over the past 18 years. However, there has been an increase in the burden of acute infections in this population. This increase is driven largely by skin and soft tissue infections. People who inject drugs often have multiple conflicting priorities that can delay engagement in care.

IMPLICATIONS

Acute infections in people who inject drugs are associated with significant morbidity and mortality. Acute infections contribute to significant bed days, surgical requirements and health-care costs in Australia. The increase in these infections is likely due to a complex interplay of microbiological, individual, social and environmental factors.

CONCLUSION

Acute infections in people who inject drugs in Australia represent a significant burden to both patients and health-care systems. Flexible health-care models, such as low-threshold wound clinics, would help directly target, and address early interventions, for these infections.

Disadvantaged by More Than Distance: A Systematic Literature Review of Injury in Rural Australia

Rural populations experience injury-related mortality and morbidity rates 1.5 times greater than metropolitan residents. Motivated by a call for stronger epidemiological evidence around rural injuries to inform prevention, a systematic review of peer-reviewed literature published between January 2010 and March 2021 was undertaken to explore the epidemiology of rural injury and associated risk factors in Australia. A subsequent aim was to explore definitions of rurality used in injury prevention studies. There were 151 papers included in the review, utilizing 23 unique definitions to describe rurality. People living in rural areas were more likely to be injured, for injuries to be more severe, and for injuries to have greater resulting morbidity than people in metropolitan areas. The increase in severity reflects the mechanism of rural injury, with rural injury events more likely to involve a higher energy exchange. Risk-taking behavior and alcohol consumption were significant risk factors for rural injury, along with rural cluster demographics such as age, sex, high socio-economic disadvantage, and health-related comorbidities. As injury in rural populations is multifactorial and nonhomogeneous, a wide variety of evidence-based strategies are needed. This requires funding, political leadership for policy formation and development, and implementation of evidence-based prevention interventions.

The impact of opioid agonist treatment on fatal and non-fatal drug overdose among people with a history of opioid dependence in NSW, Australia, 2001-2018: Findings from the OATS retrospective linkage study

BACKGROUND

There are critical periods of mortality risk at onset and cessation of opioid agonist treatment. We aim to determine whether non-fatal overdose followed the same pattern as fatal overdose, comparing the first 4 weeks of treatment and treatment cessation and the remainder time off treatment, with the remainder treatment time, to determine intervention markers.

METHODS

Retrospective cohort study of people with a history of opioid agonist treatment using linked New South Wales data. The incidence of non-fatal overdose hospitalization; emergency department presentation; and fatal overdose from national death records were compared. Rates were calculated using generalized estimating equations adjusting for demographics, year, and recent health and incarceration events.

RESULTS

The remainder time in OAT had the lowest incidence of overdose for all outcomes and is the reference level for the adjusted incident rate ratios (aIRR). Fatal overdose was lowest in treatment and highest in the first four weeks out of treatment, aIRR of 12.83 (95% CI 10.0-16.4). Whereas the highest overdose rate for non-fatal opioid overdose was in the first four weeks in treatment, aIRR of 3.11 (95% CI 2.19-4.42).

CONCLUSIONS

Retention on opioid agonist treatment is protective against drug related overdose. There is elevated risk of non-fatal overdose at treatment initiation that is not evident for fatal overdose, but the first month of treatment cessation is a critical period for both non-fatal and fatal overdose. These findings emphasize the importance of treatment retention and interventions for polysubstance overdose at cessation.

Health harms of non-medical prescription opioid use: A systematic review

ISSUES

Non-medical prescription opioid use (NMPOU) contributes substantially to the global burden of morbidity. However, no systematic assessment of the scientific literature on the associations between NMPOU and health outcomes has yet been undertaken.

APPROACH

We undertook a systematic review evaluating health outcomes related to NMPOU based on ICD-10 clinical domains. We searched 13 electronic databases for original research articles until 1 July 2021. We employed an adaptation of the Oxford Centre for Evidence-Based Medicine 'Levels of Evidence' scale to assess study quality.

KEY FINDINGS

Overall, 182 studies were included. The evidence base was largest on the association between NMPOU and mental and behavioural disorders; 71% (129) studies reported on these outcomes. Less evidence exists on the association of NMPOU with infectious disease outcomes (26; 14%), and on external causes of morbidity and mortality, with 13 (7%) studies assessing its association with intentional self-harm and 1 study assessing its association with assault (<1%).

IMPLICATIONS

A large body of evidence has identified associations between NMPOU and opioid use disorder as well as on fatal and non-fatal overdose. We found equivocal evidence on the association between NMPOU and the acquisition of HIV, hepatitis C and other infectious diseases. We identified weak evidence regarding the potential association between NMPOU and intentional self-harm, suicidal ideation and assault.

DISCUSSION AND CONCLUSIONS

Findings may inform the prevention of harms associated with NMPOU, although higher-quality research is needed to characterise the association between NMPOU and the full spectrum of physical and mental health disorders.

High-Risk Injection-Related Practices Associated with anti-HCV Positivity among Young Adults Seeking Services in Three Small Cities in Wisconsin

BACKGROUND

Hepatitis C virus (HCV) infection has been increasing among people who inject drugs (PWID), younger than 30 years, and living in rural or suburban areas. We examined injection-related behaviors of young PWID to determine factors associated with HCV infection.

METHODS

From September 2013-May 2015, respondent-driven and snowball sampling were used in 3 suburban areas of Wisconsin to recruit PWID 18-29 years who reported injection drug use in the previous 12 months. Participants were tested for HCV antibody (anti-HCV) and reported injection-related behaviors/practices via self-administered computer-based survey. We calculated anti-HCV prevalence and assessed associated factors using multivariable logistic regression.

RESULTS

Forty-two percent (117/280) of participants were male, 83% (231/280) were white, and median age was 23 years. Overall HCV prevalence was 33%, but HCV prevalence among males was 39%. Adjusting for age, sex, race/ethnicity, education, relationship status, insurance status and income, anti-HCV positivity was associated with higher injection frequency (> 100 times in the past six months) (aOR = 3.07; 95% Confidence Interval (95% CI): 1.72-5.45), ever shared syringes (aOR = 5.15; 95% CI: 2.52-10.51), past week/last use receptive rinse water sharing (aOR = 1.88; 95% CI: 1.06-3.33), past week/last use receptive filter sharing (aOR = 3.25; 95% CI: 1.61-6.54), reusing syringes (aOR = 1.91, 95% CI: 1.08-3.37), history of overdose (aOR = 8.82; 95% CI: 2.26-3.95), and having ever injected another PWID (aOR = 8.82; 95%CI 3.94-19.76).

DISCUSSION

Anti-HCV positivity is associated with high-risk injection practices. Young PWID would benefit from access to evidence-based interventions that reduce their risk of infection, link those infected to HCV treatment, and provide education to reduce further transmission.

Incidence and factors associated with discontinuation of opioid agonist therapy among people who inject drugs in Australia

AIMS

To estimate incidence and predictors of opioid agonist therapy (OAT) discontinuation in a national cohort of people who inject drugs (PWID).

DESIGN AND SETTING

Annually repeated cross-sectional serosurveillance among PWID attending ~50 needle-syringe programmes across Australia.

PARTICIPANTS

Between 1995 and 2018, 2651 PWID who reported current OAT and had subsequent survey participation completed 6739 surveys. Respondents were followed over 11 984 person-years of observation (PYO). Respondents were predominantly male (60%), and the median age was 34 years. Heroin was the most commonly reported drug last injected (46%), and methadone was the most commonly prescribed OAT (77%).

MEASUREMENTS

The primary outcome was discontinuation of OAT (methadone, buprenorphine or buprenorphine-naloxone). Among respondents who reported current OAT, those who did not report current OAT in all subsequent records were defined as discontinued, and those with current OAT at all subsequent records were defined as retained. Predictors of discontinuation included self-reported demographic (sex, location, Indigenous status) and drug use characteristics (drug last injected, frequency of injection).

FINDINGS

Just fewer than one-third of respondents (29%) reported an OAT discontinuation event. The crude discontinuation rate was 6.3 [95% confidence intervals (CI) = 5.9-6.8] per 100 PYO. Discontinuation was significantly higher among respondents who reported last injecting pharmaceutical opioids [adjusted hazard ratio (aHR) = 1.75, 95% CI = 1.41-2.17, P < 0.001], being prescribed buprenorphine (aHR = 1.44, 95% CI = 1.18-1.76, P = 0.001) or buprenorphine-naloxone (aHR = 1.68, 95% CI = 1.20-2.34, P = 0.002), daily or more frequent injection (aHR = 1.51, 95% CI = 1.23-1.85, P < 0.001), recent public injecting (aHR = 1.37, 95% CI = 1.17-1.60, P < 0.001), incarceration in the previous 12 months (aHR = 1.31, 95% CI = 1.05-1.64, P = 0.017), recent receptive syringe or injection equipment sharing (aHR = 1.28, 95% CI = 1.10-1.48, P = 0.001) and male sex (aHR = 1.27, 95% CI = 1.09-1.47, P = 0.002).

CONCLUSION

People who inject drugs attending needle-syringe programmes in Australia appear to be significantly more likely to discontinue opioid agonist treatment if they were prescribed buprenorphine or buprenorphine-naloxone compared with methadone, are male or report injection risk behaviours and recent incarceration.

Reductions in emergency department presentations associated with opioid agonist treatment vary by geographic location: A retrospective study in New South Wales, Australia

INTRODUCTION AND AIMS

It is not known if the reduction in ED use during periods of OAT occurs across urgent and low acuity presentations. We aimed to compare the incidence and costs of urgent and low acuity ED presentations of people with opioid use disorder (OUD) in and out of opioid agonist treatment (OAT).

DESIGN AND METHODS

This was a retrospective cohort study (N=24,875), using linked administrative health data from New South Wales (NSW), Australia. Urgent and low acuity ED incidence and associated costs were calculated for periods in and out of OAT. GEE models estimated the adjusted incidence rate ratio (IRR) for ED presentations. Average costs per person-day were calculated with bootstrap confidence intervals.

RESULTS

Incidence of urgent presentations was lower in OAT compared to out of OAT [IRR (95%CI): 0.65 (0.61-0.69)]. In major cities, low acuity presentations were lower during OAT compared to timeout of OAT [IRR (95%CI): 0.82 (0.70-0.96)], in regional/remote areas, low acuity presentations were higher during OAT [IRR (95%CI): 2.65 (1.66-4.21)]. In major cities, average costs for low acuity presentations in OAT were 28% lower atA$0.50 (95%CI: A$0.48-A$0.52) and A$0.69 (95%CI: A$0.66-A$0.71) out of OAT, but 103% higher in regional/remote NSW, at A$2.12 (95%CI: A$1.91-A$2.34) in OAT and A$1.04 (95%CI: A$0.91-A$1.16) out of OAT.

DISCUSSION AND CONCLUSIONS

OAT was associated with reductions in urgent ED presentations and associated costs among people with OUD. Geographical variation was evident for low acuity ED presentations, highlighting the need to increase access to OAT in regional/remote areas.

Factors underlying risk taking in heroin-dependent individuals: Feedback processing and environmental contingencies

Evidence suggests that factors influencing risk-taking include whether decisions are made based on emotions (affective systems) or cognitions (deliberative systems), the processing of feedback (e.g., deciding to attend a rehabilitation facility for opioid addiction treatment after an intervention held by a family member), and attention to environmental contingencies (e.g., considering the probability of an outcome such as the likelihood of contracting tetanus from a shared needle; or the gains and losses associated with a decision, such as the benefits and costs of taking drugs). Although drug-dependent individuals tend to take more risks than non-drug users, the factors underlying risk-taking are unknown. The current study tested, for the first time, the influences of performance feedback (i.e., whether feedback about performance is integrated into decision-making in heroin-dependent individuals) and attention to environmental contingencies (i.e., the influence of the probability of a loss, the gain amount, and the loss amount associated with a scenario) on risk-taking in heroin-dependent individuals. Heroin-dependent patients undergoing maintenance therapy for opioid addiction (n = 25) and healthy controls (n = 27) completed the feedback and no-feedback conditions of the Columbia Card Task (CCT). Analyses of covariance, controlling for education and task design (the order in which the CCT conditions were completed) as covariates revealed a significant interaction between (a) probability, gain and loss amount, and group, and (b) group and probability. Our findings suggest that heroin-dependent patients pay less attention to environmental contingencies during risk-taking than controls. Addressing these factors may facilitate greater adherence to treatment programs and lower rates of relapse.

Intravenous fentanyl use among people who inject drugs in Australia

INTRODUCTION AND AIMS

There is a current epidemic of pharmaceutical opioid (PO) misuse, particularly fentanyl and fentanyl analogues, globally. Fentanyl is a highly potent synthetic opioid with rapid onset and significantly higher risk of overdose compared with other opioids. Contexts and correlates of fentanyl use among people who inject drugs (PWID) in Australia are under-researched.

DESIGN AND METHODS

The Australian Needle Syringe Program Survey is conducted annually. Consenting PWID complete a self-administered questionnaire and provide a capillary dried blood spot for human immunodeficiency virus and hepatitis C virus antibody testing. Bivariate and multivariate logistic regressions determined correlates of recent (last 6 months) fentanyl injection in 2014.

RESULTS

Recent fentanyl injection was reported by 8% (n = 193) of the total sample. Among the 848 PWID who recently injected POs, 23% injected fentanyl. Compared with PO injectors who had not injected fentanyl, those who had injected fentanyl were significantly more likely to identify as Indigenous Australian [adjusted odds ratio (AOR) 1.61; 95% confidence interval (CI) 1.04, 2.51; P = 0.034], inject daily or more frequently (AOR 1.92; 95% CI 1.30, 2.83; P = 0.005), inject in public (AOR 1.43; 95% CI 1.01, 2.02; P = 0.042) and to have overdosed in the past year (AOR 2.16; 95% CI 1.48, 3.13; P < 0.001), but were significantly less likely to receptively share syringes (AOR 0.56; 95% CI 0.36, 0.87; P = 0.010).

DISCUSSION AND CONCLUSIONS

Fentanyl injectors in Australia are significantly more likely to identify as Indigenous, report frequent injection, inject in public and experience overdose. Increased access to harm reduction interventions, including naloxone distribution, wheel filters and supervised injection facilities, are likely to benefit this population.

Trends in hepatitis C antibody prevalence among Aboriginal and Torres Strait Islander people attending Australian Needle and Syringe Programs, 1996-2015

BACKGROUND

Research indicates that hepatitis C antibody (anti-HCV) prevalence is higher among Australian Aboriginal and Torres Strait Islander (Aboriginal) than non-Aboriginal people who inject drugs (PWID). We examined trends in demographic and drug use characteristics and anti-HCV prevalence among Australian Needle and Syringe Program Survey (ANSPS) respondents by Aboriginal status from 1996 to 2015.

METHODS

The ANSPS survey involved collecting demographic, behavioural data and a dried blood spot for anti-HCV testing. We used logistic regression to determine demographic and behavioural factors associated with testing anti-HCV positive in the following time-periods (1996-2000, 2001-2005, 2006-2010, 2011-2015) among Aboriginal and non-Aboriginal PWID respondents.

RESULTS

Overall, there were 16,948 PWID, with 11% identifying as Aboriginal. The proportion of Aboriginal respondents increased from 7% in 1996-2000 to 16% in 2011-2015. Overall anti-HCV prevalence was significantly higher among Aboriginal (60%) than non-Aboriginal PWID (52%, p<0.01). Receptive syringe sharing (RSS) declined among non-Aboriginal PWID (p<0.001) over time, however among Aboriginal PWID, RSS remained stable (p=0.619). Factors independently associated with testing positive for anti-HCV among Aboriginal PWID in 2011-2015 were 16 or more years since first injection (adjusted odds ratio [AOR] 6.04, p<0.001), history of incarceration (AOR: 1.74, p=0.010) and currently or previously on opioid substitution therapy (AOR: 1.89, p=0.003). Compared to 1996-2000, testing anti-HCV positive was significantly associated with the time-periods: 2001-2005 (unadjusted odds ratio [OR]: 1.39, p<0.001), 2006-2010 (OR: 1.38, p<0.001) and 2011-2015 (OR: 1.25, p<0.001) among non-Aboriginal PWID; however this increase did not occur among Aboriginal PWID.

CONCLUSION

The proportion of Aboriginal PWID attending Needle Syringe Programs appears to have increased. Overall, the prevalence of anti-HCV has remained higher among Aboriginal than non-Aboriginal PWID. Coupling increased access to NSPs with new interferon-free HCV treatments and culturally appropriate education and counselling services could influence new HCV infections among Aboriginal PWID.