Surveillance of injecting-related injury and diseases in people who inject drugs attending a targeted primary health care facility in Sydney's Kings Cross

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.

Acute injection-related infections requiring hospitalisation among people who inject drugs: Clinical features, microbiology and management

INTRODUCTION

People who inject drugs are at risk of hospitalisation with injection-related infections (IRI). We audited the clinical features, microbiology and management of IRI at a tertiary service in Melbourne to describe the burden and identify quality improvement opportunities.

METHODS

We performed retrospective review of IRI admissions from January 2017 to April 2019. We extracted admissions where ICD-10 codes or triage text suggested injecting drug use, and the diagnosis suggested IRI. We reviewed these for eligibility and extracted data using a standardised form. We performed mixed-effects logistic regression to determine predictors of unplanned discharge.

RESULTS

From 574 extracted candidate admissions, 226 were eligible, representing 178 patients. Median age was 41 years (interquartile range 36-47), 66% (117/178) male and 49% (111/226) had unstable housing. Over 50% (96/178) had a psychiatric diagnosis and 35% (62/178) were on opioid agonist therapy (OAT) on admission. Skin and soft tissue infection was the most common IRI (119/205, 58%), followed by bacteraemia (36/205, 18%) and endocarditis (26/205, 13%). Management included addictions review (143/226, 63%), blood-borne virus screening (115/226, 51%), surgery (77/226, 34%) and OAT commencement (68/226, 30%). Aggression events (54/226, 15%) and unplanned discharge (69/226, 30%) complicated some admissions. Opioid use without OAT was associated with almost 3-fold increased odds of unplanned discharge compared to no opioid use (odds ratio 2.90, 95% confidence interval 1.23, 6.85, p = 0.015).

DISCUSSION AND CONCLUSION

Comorbidities associated with IRI may be amenable to opportunistic intervention during hospitalisation. Further research is needed to develop optimal models of care for this vulnerable patient group.

Hospitalisation with injection-related infections: Validation of diagnostic codes to monitor admission trends at a tertiary care hospital in Melbourne, Australia

INTRODUCTION

Injection-related infections (IRI) cause morbidity and mortality in people who inject drugs. Hospital administrative datasets can be used to describe hospitalisation trends, but there are no validated algorithms to identify injecting drug use and IRIs. We aimed to validate International Classification of Diseases (ICD) codes to identify admissions with IRIs and use these codes to describe IRIs within our hospital.

METHODS

We developed a candidate set of ICD codes to identify current injecting drug use and IRI and extracted admissions satisfying both criteria. We then used manual chart review data from 1 January 2017 to 30 April 2019 to evaluate the performance of these codes and refine our algorithm by selecting codes with a high-positive predictive value (PPV). We used the refined algorithm to describe trends and outcomes of people who inject drugs with an IRI at Alfred Hospital, Melbourne from 2008 to 2020.

RESULTS

Current injecting drug use was best predicted by opioid-related disorders (F11), 80% (95% confidence interval [CI] 74-85%), and other stimulant-related disorders (F15), 82% (95% CI 70-90%). All PPVs were ≥67% to identify specific IRIs, and ≥84% for identifying any IRI. Using these codes over 12 years, IRIs increased from 138 to 249 per 100 000 admissions, and skin and soft tissues infections (SSTI) were the most common (797/1751, 46%).

DISCUSSION AND CONCLUSION

Validated ICD-based algorithms can inform passive surveillance systems. Strategies to reduce hospitalisation with IRIs should be supported by early intervention and prevention, particularly for SSTIs which may represent delayed access to care.

Estimating the number of new hepatitis C infections in Australia in 2015, prior to the scale-up of direct-acting antiviral treatment

BACKGROUND AND AIM

The recent downward revision of the estimated number of people living with chronic hepatitis C in Australia means that the annual number of new hepatitis C infections should also be revised. We aimed to estimate the annual number of new hepatitis C infections among people who inject drugs (PWID) in Australia in 2015, prior to the introduction of direct-acting antiviral (DAA) treatment for hepatitis C, as an updated baseline measure for assessing the impact of DAAs on hepatitis C incidence over the next 10 years.

METHODS

A systematic review identified articles estimating hepatitis C incidence rates among PWID between 2002 and 2015. Reported incidence rates were adjusted to account for unrepresentative needle and syringe program (NSP) coverage among study participants compared with PWID overall. The total number of PWID in Australia and the hepatitis C RNA prevalence among PWID were taken from published estimates. The annual number of new infections was estimated by multiplying the pooled NSP coverage-adjusted incidence rate by the number of susceptible PWID in 2015.

RESULTS

Five studies were included, with unadjusted incidence rates ranging from 7.6 to 12.8 per 100 person-years. The overall pooled incidence rate (after adjusting for NSP coverage) was 9.9 per 100 person-years (95% confidence interval: 8.3-11.8). This led to an estimate of 4126 (range 2499-6405) new hepatitis C infections in 2015.

CONCLUSIONS

Our updated estimate provides an important baseline for evaluating the impact of hepatitis C elimination efforts and can be used to validate outcomes of future modeling studies.

The Clinical and Financial Burden of Spinal Infections in People who Inject Drugs

BACKGROUND

People who inject drugs (PWID) are known to be at increased risk of infectious diseases including bacterial and blood-borne viral infections. However, there is limited literature surrounding the burden of spinal infections as a complication of injecting drug use (IDU).

AIMS

To quantify the clinical and financial burden of IDU-related spinal infections.

METHODS

Retrospective chart review of adult PWID with spinal infections requiring hospital admission to a tertiary health service in Melbourne, Australia between 2011 and 2019.

RESULTS

Fifty-seven PWID with 63 episodes of spinal infections were identified with a median hospital stay of 47 days (IQR 16, range 4-243). One-third of episodes required neurosurgical intervention and 11 episodes (17%) required intensive care unit (ICU) admission (range 2-17 days). Staphylococcus aureus was the most common causative pathogen, present in three-quarters of all episodes (n = 47). The median duration of antibiotic regime was 59 days (IQR 42) and longer courses were associated with known bacteraemia (p = 0.048), polymicrobial infections (p = 0.001) and active IDU (p = 0.066). Predictors of surgery include neurological symptoms at presentation (RR 2.6; p = 0.010), inactive IDU status (RR 3.0; p = 0.002), a diagnosis of epidural abscess (RR 4.1; p = 0.001) and spinal abscess (RR ∞; p < 0.001). Completion of planned antimicrobial therapy was reported in 51 episodes (82%). Average expenditure per episode was AUD $61 577.

CONCLUSIONS

Spinal infections in PWID are an underreported serious medical complication of IDU. Though mortality is low, there is significant morbidity with prolonged admissions, large antimicrobial requirements and surgical interventions generating a substantial cost to the health system. This article is protected by copyright. All rights reserved.

Estimating the number of people who inject drugs and syringe coverage in Australia, 2005-2016

BACKGROUND

Effective targeting of harm reduction programs for people who inject drugs (PWID) requires timely and robust estimates of the size of this population. This study estimated the number of people who inject drugs on a regular basis in Australia, calculated syringe coverage per person and the proportion of their injections covered by a sterile needle and syringe.

METHODS

We used trends in indicators of injection drug use to extend the 2005 estimate of the population of people who regularly inject drugs from 2005 to 2016. Included indicators were lifetime/recent injection of illicit drugs, drug-related arrests, drug-related seizures, accidental deaths due to opioids, opioid-related hospital admissions/separations and new diagnoses of hepatitis C virus infection among those aged 15-24 years. Syringe distribution and frequency of injection data were used to assess syringe coverage per PWID and the proportion of their injections covered by a sterile syringe.

RESULTS

The estimated number of people who regularly inject drugs in Australia increased by 7%, from 72,000 in 2005 to 77,270 in 2016. The annual number of syringes distributed per person increased 34%, from 470 syringes in 2005 to 640 syringes in 2016. Syringe coverage per injection first exceeded 100% in Australia in 2013.

CONCLUSIONS

Despite Australia's high syringe coverage by international standards, the number of syringes distributed is likely to be only narrowly meeting demand. It is critical that needle syringe programs be provided with sufficient resources to continue their role as the key intervention required to prevent HIV and HCV transmission among PWID.

Acceptability and preferences of point-of-care finger-stick whole-blood and venepuncture hepatitis C virus testing among people who inject drugs in Australia

BACKGROUND

Uptake of hepatitis C virus (HCV) testing remains inadequate globally. Simplified point-of-care tests should enhance HCV diagnosis and elimination. We aimed to assess the acceptability of finger-stick and venepuncture HCV RNA testing among people who inject drugs (PWID).

METHODS

Participants were enrolled in an observational cohort study with recruitment at 13 sites between June 2016 and February 2018. Capillary whole-blood collected by finger-stick and plasma collected by venepuncture were performed for Xpert^® HCV viral load testing. Participants completed a questionnaire on acceptability of, and preferences for, blood collection methods.

RESULTS

Among 565 participants (mean age, 44 years; 69% male), 64% reported injecting drugs in the last month, and 63% were receiving opioid substitution treatment. Eighty three percent reported that finger-stick testing was very acceptable. Overall, 65% of participants preferred finger-stick over venepuncture testing, with 61% of these preferring to receive results in 60 min. The most common reason for preferring finger-stick over venepuncture testing was it was quick (62%) followed by venous access difficulties (21%). The main reasons for preferring venepuncture over finger-stick testing were that it was quick (61%) and accurate (29%). Females were more likely to prefer finger-stick testing than males (adjusted OR 1.96; 95% CI 1.30, 2.99; p = 0.002). Among people with recent (previous month) injecting drug use, Aboriginal and/or Torres Strait Islander people were less likely than non-Aboriginal people to prefer finger-stick testing (adjusted OR 0.57; 95% CI 0.34, 0.9; p = 0.033).

CONCLUSIONS

Finger-stick whole-blood collection is acceptable to people who inject drugs, with males and Aboriginal and/or Torres Strait Islander people with recent injecting drug use less likely to prefer finger-stick testing. Further research is needed to evaluate interventions integrating simplified point-of-care HCV testing to engage people in care in a single-visit, thereby facilitating HCV treatment scale-up.

A prospective cohort study of hospital separations among people who inject drugs in Australia: 2008-2013

OBJECTIVES

Injecting drug use is a persistent behaviour that increases the risk of morbidities and mortality. We assessed the burden of hospital separations among people who inject drugs (PWID), the excess compared to the general population and characteristics of separations associated with frequent use.

DESIGN

Prospective cohort study.

SETTING

All public and private hospitals in Victoria.

PARTICIPANTS

757 community-based PWID with hospital separations between January 2008 and June 2013 identified through record linkage, who contributed over 3729 person-years.

PRIMARY AND SECONDARY OUTCOME MEASURES

Counts, proportions and rates of hospital separations, descriptive administrative data including all diagnoses, comparison of separation rates to the general population, trend in separations and factors associated with frequent separations.

RESULTS

There were 2106 separations in the cohort. The most common principal diagnoses were related to mental and behavioural disorders (31%), but social circumstances influencing health was the most common group of diagnoses (61%) when all contributing diagnoses for each patient were considered. Separation rates were up to three times higher than in the age-matched population, and there was a 12% increase in separations every 6 months. Over a quarter (29%) of the cohort had frequent separations (defined as two or more separations in a calendar year), which were associated with mental health-related diagnoses, being discharged to locations other than a patient's residence, having a medical as opposed to surgical intervention, seasonal patterns, relationship status and gender.

CONCLUSIONS

Mental health conditions and other characteristics associated with separations and frequent separations in particular, emphasise the importance of providing referrals to harm reduction, social services and mental health services at discharge in order to reduce excess hospital separations among PWID.

Physical pain is common and associated with nonmedical prescription opioid use among people who inject drugs

Background

People who inject drugs (PWID) often have poor health and lack access to health care. The aim of this study was to examine whether PWID engage in self-treatment through nonmedical prescription opioid use (NMPOU). We describe the prevalence and features of self-reported physical pain and its association with NMPOU.

Methods

PWID (N = 702) in San Francisco, California (age 18+) were recruited to complete interviewer administered surveys between 2011 and 2013. Multivariate logistic regression analysis was conducted to examine the associations among self-reported pain dimensions (past 24-h average pain, pain interference with functional domains) and NMPOU, controlling for age, sex, psychiatric illness, opioid substitution treatment, homelessness, street heroin use and unmet healthcare needs.

Results

Almost half of the sample reported pain, based on self-reported measures in the 24 h before their interview. The most common pain locations were to their back and lower extremities. Past 24-h NMPOU was common (14.7%) and associated with past 24 h average pain intensity on a 10 point self-rating scale (adjusted odds ratio [AOR] = 2.15, 95% confidence interval [CI] 1.21–3.80), and past 24 h pain interference with general activity (AOR 1.82 [95% CI 1.04–3.21]), walking ability (AOR 2.52 [95% CI 1.37–4.63]), physical ability (AOR 2.01 [95% CI 1.16–3.45]), sleep (AOR 1.98 [95% CI 1.13–3.48]) and enjoyment of life (AOR 1.79 [95% CI 1.02–3.15]).

Conclusion

Both pain and NMPOU are common among PWID, and highly correlated in this study. These findings suggest that greater efforts are needed to direct preventive health and services toward this population.