The Current Epidemiology of Injecting Drug Use-Associated Infective Endocarditis in Victoria, Australia in the Midst of Increasing Crystal Methamphetamine Use

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.

Social and structural determinants of injection drug use-associated bacterial and fungal infections: A qualitative systematic review and thematic synthesis

BACKGROUND AND AIMS

Injection drug use-associated bacterial and fungal infections are increasingly common, and social contexts shape individuals' injecting practices and treatment experiences. We sought to synthesize qualitative studies of social-structural factors influencing incidence and treatment of injecting-related infections.

METHODS

We searched PubMed, EMBASE, Scopus, CINAHL and PsycINFO from 1 January 2000 to 18 February 2021. Informed by Rhodes' 'risk environment' framework, we performed thematic synthesis in three stages: (1) line-by-line coding; (2) organizing codes into descriptive themes, reflecting interpretations of study authors; and (3) consolidating descriptive themes into conceptual categories to identify higher-order analytical themes.

RESULTS

We screened 4841 abstracts and included 26 qualitative studies on experiences of injecting-related bacterial and fungal infections. We identified six descriptive themes organized into two analytical themes. The first analytical theme, social production of risk, considered macro-environmental influences. Four descriptive themes highlighted pathways through which this occurs: (1) unregulated drug supply, leading to poor drug quality and solubility; (2) unsafe spaces, influenced by policing practices and insecure housing; (3) health-care policies and practices, leading to negative experiences that discourage access to care; and (4) restrictions on harm reduction programmes, including structural barriers to effective service provision. The second analytical theme, practices of care among people who use drugs, addressed protective strategies that people employ within infection risk environments. Associated descriptive themes were: (5) mutual care, including assisted-injecting and sharing sterile equipment; and (6) self-care, including vein health and self-treatment. Within constraining risk environments, some protective strategies for bacterial infections precipitated other health risks (e.g. HIV transmission).

CONCLUSIONS

Injecting-related bacterial and fungal infections are shaped by modifiable social-structural factors, including poor quality unregulated drugs, criminalization and policing enforcement, insufficient housing, limited harm reduction services and harmful health-care practices. People who inject drugs navigate these barriers while attempting to protect themselves and their community.

Epidemiology and Management of invasive infections among people who Use drugs (EMU): protocol for a prospective, multicentre cohort study

INTRODUCTION

People who inject drugs (PWID) are at risk of invasive infections such as bloodstream infections, endocarditis, osteomyelitis and septic arthritis. Such infections require prolonged antibiotic therapy, but there is limited evidence about the optimal care model to deliver to this population. The Epidemiology and Management of invasive infections among people who Use drugs (EMU) study aims to (1) describe the current burden, clinical spectrum, management and outcomes of invasive infections in PWID; (2) determine the impact of currently available models of care on completion of planned antimicrobials for PWID admitted to hospital with invasive infections and (3) determine postdischarge outcomes of PWID admitted with invasive infections at 30 and 90 days.

METHODS AND ANALYSIS

EMU is a prospective multicentre cohort study of Australian public hospitals who provide care to PWIDs with invasive infections. All patients who have injected drugs in the previous six months and are admitted to a participating site for management of an invasive infection are eligible. EMU has two components: (1) EMU-Audit will collect information from medical records, including demographics, clinical presentation, management and outcomes; (2) EMU-Cohort will augment this with interviews at baseline, 30 and 90 days post-discharge, and data linkage examining readmission rates and mortality. The primary exposure is antimicrobial treatment modality, categorised as inpatient intravenous antimicrobials, outpatient antimicrobial therapy, early oral antibiotics or lipoglycopeptide. The primary outcome is confirmed completion of planned antimicrobials. We aim to recruit 146 participants over a 2-year period.

ETHICS AND DISSEMINATION

EMU has been approved by the Alfred Hospital Human Research Ethics Committee (Project number 78815.) EMU-Audit will collect non-identifiable data with a waiver of consent. EMU-Cohort will collect identifiable data with informed consent. Findings will be presented at scientific conferences and disseminated by peer-review publications.

TRIAL REGISTRATION NUMBER

ACTRN12622001173785; Pre-results.

The Epidemiology of Infective Endocarditis in New South Wales, Australia: A Retrospective Cross-Sectional Study From 2001 to 2020

OBJECTIVES

This study aimed to investigate the demographic differences amongst patients diagnosed with infective endocarditis (IE), predictors of adverse events, and the association between clinical decision-making and adverse health outcomes amongst patients with IE.

DESIGN

A retrospective cross-sectional study was conducted using the New South Wales (NSW) Admitted Patient Data Collection (APDC) from the Centre for Health Record Linkage (CHeReL).

PARTICIPANTS

All patients (N=18,044) from 2001 to 2020 in New South Wales who received a diagnosis of IE using ICD-10-AM diagnostic code 133.0 were included.

METHODS

Categorical variables were compared using the chi-square test or Fisher's exact test, while the t-test was used for continuous variables. The association between clinical decision-making and adverse health outcomes amongst patients with IE were examined via generalised linear mixed models.

RESULTS

Sex, age, birthplace and referral impacted clinical decision-making, in-hospital death and severity of the disease. Women experienced a higher risk of death and fewer escalations of care. Admission and mortality increased with age, with those aged 60 and above responsible for 60.8% of hospitalisations. Despite octogenarians making up one-fifth of admissions and having the worst mortality rate (15.1%), they experienced only one in 10 intensive care (ICU) admissions. Overseas-born patients had fewer escalations of care and experienced less severe disease if referred by a medical practitioner. One out of 10 admissions that resulted in a hospital death were given non-emergency status, and one in two ICU patients died in hospital.

CONCLUSIONS

Sex, age, place of birth, and clinical decision-making were important predictors of severe disease and death in hospital, lending weight that health care clinical decisions may adversely impact health outcomes for populations of interest.

Haemorrhagic mesenteric abscess in infective endocarditis: a unique cause of spontaneous haemoperitoneum

Spontaneous haemoperitoneum (SH) is a rare but life-threatening condition with several well-recognized causes. SH often occurs in anticoagulated patients and requires urgent treatment to prevent mortality. SH is rarely associated with infective endocarditis (IE). To date, there are no reported cases of a haemorrhagic mesenteric abscess causing haemoperitoneum. We present the case of a warfarinized 30-year-old intravenous drug user with IE 2 weeks post-revision of a metallic valve who reported abdominal pain and subsequently suffered haemodynamic collapse. Abdominal computed tomography and damage-control laparotomy revealed haemoperitoneum secondary to an actively bleeding mesenteric nodule which was resected. Histopathology confirmed a haemorrhagic mesenteric abscess representing a rare sequela of IE and a novel cause of SH. Given that the incidence of IE appears to be increasing in people who inject drugs in Australia, the general surgeon should be aware of this clinical entity and the need for urgent intervention to prevent catastrophic sequelae.

Multivalve infective endocarditis in intravenous drug using patients: an epidemiological study

BACKGROUND

Infective endocarditis (IE) remains a life-threatening condition. Intravenous drug use (IVDU) adds to the clinical challenge associated with IE due to clinical aberrations caused by the social issues associated with this population.

AIM

To improve survival, this study aimed to characterize the contemporary IVDU-associated IE population seen at our tertiary hospital, determine their long-term outcomes and find risk factors associated with mortality.

DESIGN

Retrospective observational cohort study.

METHODS

A total of 79 patients accounting for 89 presentations were treated for IVDU-associated IE at St Vincent's Hospital Melbourne (SVHM) between 1999 and 2015. Patients were followed-up until death or January 2021. The primary outcome was all-cause mortality and Kaplan-Meier survival analysis was used to calculate long-term survival estimates. Cox proportional hazards analysis was used to examine risk factors for mortality.

RESULTS

The IVDU population treated at SVHM had a high rate of multivalvular IE, at 18.98%. Multivariate analysis revealed that multivalvular IE is significantly associated with an increased risk of mortality in a dose-dependent relationship (two valves affected: HR = 4.73, P = 0.006, three valves affected: HR = 14.19, P = 0.014). The IVDU population has survival estimates of 83.78% (95%CI: 73.21-90.45%) at 1-year and 64.98% (95%CI: 50.94-75.92%) at 15-years.

CONCLUSION

IVDU patients have high rates of multivalvular endocarditis, which is associated with increased risk of mortality and difficult to identify on echocardiography. Clinicians should be suspicious of multivalve involvement in the IVDU population and decisions related to medical management/intervention should be made with the understanding that these patients are at a higher risk of death.

The impact of opioid agonist treatment on hospitalisations for injecting-related diseases among an opioid dependent population: A retrospective data linkage study

BACKGROUND

Injecting-related bacterial and fungal infections cause substantial illness and disability among people who use illicit drugs. Opioid agonist treatment (OAT) reduces injecting frequency and the transmission of blood borne viruses. We estimated the impact of OAT on hospitalisations for non-viral infections and examine trends in incidence over time.

METHODS

We conducted a retrospective cohort study using linked administrative data. The cohort included 47 163 individuals starting OAT between August 2001 and December 2017 in New South Wales, Australia, with 454 951 person-years of follow-up. The primary outcome was hospitalisation for an injecting-related disease. The primary exposure was OAT status (out of OAT, first four weeks of OAT, and OAT retention [i.e., more than four weeks in treatment]). Covariates included demographic characteristics, year of hospitalisation, and recent clinical treatment.

RESULTS

9122 participants (19.3%) had at least one hospitalisation for any injecting-related disease. Compared to time out of treatment, retention on OAT was associated with a reduced rate of injecting-related diseases (adjusted rate ratio[ARR]=0.92; 95%CI 0.87-0.97). The first four weeks of treatment was associated with an increased rate (ARR 1.53, 95%CI 1.38-1.70), which we believe is explained by referral pathways between hospital and community OAT services. The age-adjusted incidence rates of hospitalisations for any injecting-related disease increased from 34.8 (95% CI =30.2-40.0) per 1000 person-years in 2001 to 54.9 (95%CI=51.3-58.8) in 2017.

INTERPRETATION

Stable OAT is associated with reduced hospitalisations for injecting-related bacterial infections; however, OAT appears insufficient to prevent these harms as the rate of these infections is increasing in Australia.

Opioid agonist treatment and risk of death or rehospitalization following injection drug use-associated bacterial and fungal infections: A cohort study in New South Wales, Australia

BACKGROUND

Injecting-related bacterial and fungal infections are associated with significant morbidity and mortality among people who inject drugs (PWID), and they are increasing in incidence. Following hospitalization with an injecting-related infection, use of opioid agonist treatment (OAT; methadone or buprenorphine) may be associated with reduced risk of death or rehospitalization with an injecting-related infection.

METHODS AND FINDINGS

Data came from the Opioid Agonist Treatment Safety (OATS) study, an administrative linkage cohort including all people in New South Wales, Australia, who accessed OAT between July 1, 2001 and June 28, 2018. Included participants survived a hospitalization with injecting-related infections (i.e., skin and soft-tissue infection, sepsis/bacteremia, endocarditis, osteomyelitis, septic arthritis, or epidural/brain abscess). Outcomes were all-cause death and rehospitalization for injecting-related infections. OAT exposure was classified as time varying by days on or off treatment, following hospital discharge. We used separate Cox proportional hazards models to assess associations between each outcome and OAT exposure. The study included 8,943 participants (mean age 39 years, standard deviation [SD] 11 years; 34% women). The most common infections during participants' index hospitalizations were skin and soft tissue (7,021; 79%), sepsis/bacteremia (1,207; 14%), and endocarditis (431; 5%). During median 6.56 years follow-up, 1,481 (17%) participants died; use of OAT was associated with lower hazard of death (adjusted hazard ratio [aHR] 0.63, 95% confidence interval [CI] 0.57 to 0.70). During median 3.41 years follow-up, 3,653 (41%) were rehospitalized for injecting-related infections; use of OAT was associated with lower hazard of these rehospitalizations (aHR 0.89, 95% CI 0.84 to 0.96). Study limitations include the use of routinely collected administrative data, which lacks information on other risk factors for injecting-related infections including injecting practices, injection stimulant use, housing status, and access to harm reduction services (e.g., needle exchange and supervised injecting sites); we also lacked information on OAT medication dosages.

CONCLUSIONS

Following hospitalizations with injection drug use-associated bacterial and fungal infections, use of OAT is associated with lower risks of death and recurrent injecting-related infections among people with opioid use disorder.

Dealing with the epidemic of endocarditis in people who inject drugs

North America is facing an opioid epidemic and growing illicit drug supply, contributing to growing numbers of injection drug use-related infective endocarditis (IDU-IE). Patients with IDU-IE have high early and late mortality. Patients with IDU-IE more commonly present with right-sided IE compared to those with non-IDU-IE and a majority are a result of S. aureus. While most patients can be successfully managed with intravenous antibiotic treatment, surgery is often required in part related to high relapse rates, potential treatment biases, and more aggressive pathophysiology in some. Multidisciplinary management as endocarditis teams, including not only cardiologists and cardiac surgeons but also infectious disease specialists, drug addiction experts, social workers, neurologists and/or neurosurgeons, is essential to best manage substance use disorder and facilitate safe discharge to home and society. Structural and population-level interventions, such as harm reduction programs, are necessary to reduce IDU-IE relapse rates in the community and other IDU-related health concerns such as overdoses. In this review, we describe the pathophysiological, clinical, surgical, social, and ethical characteristics of IDU-IE and the management thereof. We present the most recent clinical guidelines for this condition and discuss existing gaps in knowledge to guide future research, practice changes, and policy interventions.

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.

Epidemiology of infective endocarditis: novel aspects in the twenty-first century

INTRODUCTION

The epidemiology of infective endocarditis (IE) in this millennium has changed with emergence of new risk factors and reemergence of others. This, coupled with modifications in national guidelines in the setting of a pandemic, prompted an address of the topic.

AREAS COVERED

Our goal is to provide a contemporary review of IE epidemiology considering changing incidence of rheumatic heart disease (RHD), cardiac device implantation, and injection drug use (IDU), with SARS-CoV-2 pandemic as the backdrop.

METHODS

PubMed and Google Scholar were used to identify studies of interest.

EXPERT OPINION

Our experience over the past two decades verifies the notion that there is not one 'textbook' profile of IE. Multiple factors have dramatically impacted IE epidemiology, and these factors differ, based, in part on geography. RHD has declined in many areas of the world, whereas implanted cardiovascular devices-related IE has grown exponentially. Perhaps the most influential, at least in areas of the United States, is injection drug use complicating the opioid epidemic. Healthy younger individuals contracting a potentially life-threatening infection has been tragic. In the past year, epidemiological changes due to the COVID-19 pandemic have also occurred. No doubt, changes will characterize IE in the future and serial review of the topic is warranted.

The Epidemiology of Endocarditis in Manitoba: A Retrospective Study

Background

Recently, anecdotal evidence suggested an increase in infective endocarditis (IE) in Manitoba driven by an increasing proportion of patients with intravenous drug use (IVDU)-associated endocarditis. This study aimed to characterize the observed changing incidence and epidemiology of IE.

Methods

This retrospective study evaluated consecutive patients >18 years old with an International Classification of Disease–10 diagnosis of IE who presented to a tertiary referral center in Winnipeg, Manitoba between January 1, 2004 and December 31, 2018. Data were obtained by individual review of paper and electronic medical records and entered into the Research Electronic Data Capture database. Mortality and hospital readmission data were acquired by linking Research Electronic Data Capture data to the Manitoba Centre for Health Policy, which prospectively maintains a comprehensive population-based health database.

Results

A total of 612 cases of IE were identified. The incidence of IE increased from 2.03 per 100,000 in 2004 to 5.16 per 100,000 in 2018, with IVDU-associated cases increasing from 0.11 to 2.87 per 100,000. Left heart vegetations were most common in the non-IVDU group, whereas right-sided vegetations dominated in the IVDU group. All-cause mortality did not differ between IVDU and non-IVDU IE, despite a significantly younger age in patients with IVDU. The IVDU group showed a higher rate of endocarditis recurrence.

Conclusions

In this first study to examine the longitudinal incidence of IE in Manitoba, we showed that the incidence of IE has significantly increased over the last 15 years, with a contribution of IVDU-associated IE that has a high rate of mortality and disease recurrence.

Social and structural determinants of injecting-related bacterial and fungal infections among people who inject drugs: protocol for a mixed studies systematic review

INTRODUCTION

Injecting-related bacterial and fungal infections are a common complication among people who inject drugs (PWID), associated with significant morbidity and mortality. Invasive infections, including infective endocarditis, appear to be increasing in incidence. To date, preventive efforts have focused on modifying individual-level risk behaviours (eg, hand-washing and skin-cleaning) without much success in reducing the population-level impact of these infections. Learning from successes in HIV prevention, there may be great value in looking beyond individual-level risk behaviours to the social determinants of health. Specifically, the risk environment conceptual framework identifies how social, physical, economic and political environmental factors facilitate and constrain individual behaviour, and therefore influence health outcomes. Understanding the social and structural determinants of injecting-related bacterial and fungal infections could help to identify new targets for prevention efforts in the face of increasing incidence of severe disease.

METHODS AND ANALYSIS

This is a protocol for a systematic review. We will review studies of PWID and investigate associations between risk factors (both individual-level and social/structural-level) and the incidence of hospitalisation or death due to injecting-related bacterial infections (skin and soft-tissue infections, bacteraemia, infective endocarditis, osteomyelitis, septic arthritis, epidural abscess and others). We will include quantitative, qualitative and mixed methods studies. Using directed content analysis, we will code risk factors for these infection-related outcomes according to their contributions to the risk environment in type (social, physical, economic or political) and level (microenvironmental or macroenvironmental). We will also code and present risk factors at each stage in the process of drug acquisition, preparation, injection, superficial infection care, severe infection care or hospitalisation, and outcomes after infection or hospital discharge.

ETHICS AND DISSEMINATION

As an analysis of the published literature, no ethics approval is required. The findings will inform a research agenda to develop and implement social/structural interventions aimed at reducing the burden of disease.

PROSPERO REGISTRATION NUMBER

CRD42021231411.

ENDOGENOUS ENDOPHTHALMITIS IN WESTERN AUSTRALIA: A Sixteen-Year Retrospective Study

PURPOSE

To review the clinical features, microbiology spectrum, management, and outcomes of patients with endogenous endophthalmitis in Western Australia over a 16-year period.

METHODS

This is a retrospective chart review of all patients with endogenous endophthalmitis who presented to all tertiary ophthalmology departments between 2000 and 2015 in Western Australia.

RESULTS

Sixty-six eyes of 57 patients with endogenous endophthalmitis were identified, and follow-up data were available for a mean of 554 days. The average frequency was 1.6 per 1,000,000 population per year. Diabetes mellitus (33%) and intravenous drug use (30%) were the most common risk factors. Concurrent systemic infections included urinary tract infection (28%), pneumonia (23%), and endocarditis (21%). Among culture-positive cases (93%), 57% were bacterial and 43% were fungal. Visual acuity improved in 33 (50%) and declined in 15 eyes (22.7%). Baseline visual acuity and the presence of Gram-negative or filamentous fungi were the only predictors of final visual acuity (P = 0.023 and P = 0.001).

CONCLUSION

The population frequency of endogenous endophthalmitis has not changed over 16 years despite the changing profile of pathogen and risk factors. Similar to previous studies in Asian and Western countries, visual and anatomical prognosis depends on initial visual acuity and isolated pathogen. Gram-negative and filamentous fungi culture predicted a worse visual outcome.

Right-Sided Infective Endocarditis: The Importance of Vegetation Size

BACKGROUND

Right-sided infective endocarditis (IE) carries favourable prognosis compared to left-sided IE. However, the prognostic significance of vegetation size in right-sided IE is less well defined. This study reports the clinical, microbiological, and echocardiographic findings associated with right-sided IE and examines the predictors of adverse outcomes.

METHODS

Consecutive adults admitted with isolated right-sided IE at an Australian tertiary referral centre between June 1999 and May 2017 were retrospectively reviewed. Patients were stratified according to intravenous drug user (IVDU) status. Culprit organisms, sepsis severity, treatment regimens, inpatient complications, and vegetation size were recorded. Hospital survivors were followed mean 6.9±4.8 years for late mortality and IE recurrence.

RESULTS

Of 318 consecutive cases of IE, 60 (19%) were isolated right-sided IE and included in this study. Forty-three (43) (72%) patients were current IVDUs, who were younger and more likely to have hepatitis. The majority (90%) of patients were medically managed with multi-agent antimicrobial regimens (median three agents) for a total duration of median 91 days. In-hospital mortality was 3% (2/60). Septic emboli were found in 82% (49/60) of patients, were significantly more common among IVDUs but were not related to vegetation size. Survival after hospital discharge was 100% at 1 year, 96% at 3 years, and 89% at 5 years. Vegetation size >2 cm, chronic kidney disease, and Pitt bacteraemia score were independent predictors of all-cause late mortality. Freedom from IE recurrence was 93% at 1 year, 87% at 3 years, and 84% at 5 years. Vegetation >2.5 cm, prisoner status, and multivalvular IE involvement conferred higher risks of recurrence.

CONCLUSIONS

Patients with right-sided IE and small vegetations do well with medical management and this should continue to be the preferred strategy. However, those with large vegetations have poorer late outcomes and may require more aggressive treatment and closer follow-up.

Secular trends in the epidemiology and clinical characteristics of Enterococcus faecalis infective endocarditis at a referral center (2007-2018)

The aim of the study was to analyze the epidemiological and clinical changes in EFIE. All definite IE episodes treated at a referral center between 2007 and 2018 were registered prospectively, and a trend test was used to study etiologies over time. EFIE cases were divided into three periods, and clinical differences between them were analyzed. All episodes of E. faecalis monomicrobial bacteremia (EFMB) between 2010 and 2018 and the percentage of echocardiograms performed were retrospectively collected. Six hundred forty-eight IE episodes were studied. We detected an increase in the percentage of EFIE (15% in 2007, 25.3% in 2018, P = 0.038), which became the most prevalent causative agent of IE during the last study period. One hundred and eight EFIE episodes were analyzed (2007-2010, n = 30; 2011-2014, n = 22; 2015-2018, n = 56). The patients in the last period were older (median 70.9 vs 66.5 vs 76.3 years, P = 0.015) and more frequently had an abdominal origin of EFIE (20% vs 13.6% vs 42.9%, P = 0.014), fewer indications for surgery (63.3% vs 54.6% vs 32.1%, P = 0.014), and non-significantly lower in-hospital mortality (30% vs 18.2% vs 12.5%, P = 0.139). There was an increase in the percentage of echocardiograms performed in patients with EFMB (30% in 2010, 51.2% in 2018, P = 0.014) and EFIE diagnoses (15% in 2010, 32.6% in 2018, P = 0.004). E. faecalis is an increasing cause of IE in our center, most likely due to an increase in the percentage of echocardiograms performed. The factors involved in clinical changes in EFIE should be thoroughly studied.

Profile and correlates of injecting-related injuries and diseases among people who inject drugs in Australia

INTRODUCTION

People who inject drugs (PWID) commonly experience harms related to their injecting, many of which are consequences of modifiable drug use practices. There is currently a gap in our understanding of how certain injecting-related injuries and diseases (IRID) cluster together, and socio-demographic and drug use characteristics associated with more complex clinical profiles.

METHOD

Surveys were conducted with 902 Australian PWID in 2019. Participants provided information regarding their drug use, and past month experience of the following IRID: artery injection, nerve damage, skin and soft tissue infection, thrombophlebitis, deep vein thrombosis, endocarditis, septic arthritis, osteomyelitis, and septicaemia. We performed a latent class analysis, grouping participants based on reported IRID and ran a class-weighted regression analysis to determine variables associated with class-membership.

RESULTS

One-third (34 %) of the sample reported any IRID. A 3-class model identified: 1) no IRID (73 %), moderate IRID (21 %), and 3) high IRID (6%) clusters. Re-using one`s own needles was associated with belonging to the high IRID versus moderate IRID class (ARRR = 2.38; 95 % CI = 1.04-5.48). Other factors, including daily injecting and past 6-month mental health problems were associated with belonging to moderate and high IRID classes versus no IRID class.

CONCLUSION

A meaningful proportion of PWID reported highly complex IRID presentations distinguished by the presence of thrombophlebitis and associated with greater re-use of needles. Increasing needle and syringe coverage remains critical in addressing the harms associated with injecting drug use and expanding the capacity of low-threshold services to address less severe presentations might aid in reducing IRID amongst PWID.

Outpatient Antimicrobial Therapy for Infective Endocarditis is Safe

Infective endocarditis (IE) is common and is associated with significant mortality, morbidity and health care burden. Outpatient antimicrobial therapy in carefully selected patients, supported by a multidisciplinary team is safe and beneficial for both the patient and the health care system. In this article, we review current literature of outpatient antimicrobial therapy in infective endocarditis and propose that most patients with IE should be considered and appropriate pathways developed to facilitate this.

Widespread septic embolization in injection drug use mitro-aortic infective endocarditis as a remote cause of death

Injection drug use-related infective endocarditis (IDU-IE) assumes peculiar epidemiological, pathogenetic, and prognostic characteristics that allow to consider it a distinct nosological entity, as well as a current problem of considerable social weight. Incidence is reasonably underestimated because diagnosis is often accidental in postmortem examination when drug-related death is suspected. In many cases, postmortem toxicological examinations are negative for acute drug abuse, and findings of infective endocarditis became relevant in the explanation of the mechanism of death. Extracardiac involvement of infective endocarditis is rarely reported as fatal. Fragmentation and embolization of bacterial vegetations can be associated with parenchymal infarcts, systemic spread of the infectious process by formation of an abscess. A case of septic shock as a consequence of the constant bacteremia determined by the continuous proliferation and release of bacteria into the circulation is presented in an injection drug user with left-sided endocarditis and widespread septic embolization. Authors reviewed forensic and medical literature and promote epidemiological value of medical and forensic autopsy. Extracardiac involvement of infective endocarditis may represent a remote and alternative cause of death in injection drug users, and an early diagnosis can be relevant for prognosis. Postmortem examination still represents a valuable opportunity of learning for clinicians and improving diagnostic accuracy with injection drug users. A call for changing of attitudes and practice toward autopsy is finally demanded.

A retrospective cohort study evaluating correlates of deep tissue infections among patients enrolled in opioid agonist treatment using administrative data in Ontario, Canada

Objective

The objective of this study was to evaluate the relationship between individual characteristics and deep tissue infections in patients enrolled in opioid agonist treatment in Ontario, Canada.

Methods

A retrospective cohort study was conducted on patients in opioid agonist treatment between January 1, 2011, and December 31, 2015 in Ontario, Canada. Patients were identified using data from the Ontario Health Insurance Plan Database, and the Ontario Drug Benefit Plan Database. We identified other study variables including all-cause mortality using data from the Registered Persons Database. Encrypted patient identifiers were used to link across databases. Logistic regression models were used to measure potential correlates of deep tissue infections.

Results

An increase in the incidence of deep tissue infections was observed between 2011 and 2016 for patients on opioid agonist treatment. Additionally, age, sex, positive HIV diagnosis, and all-cause mortality was correlated with deep tissue infection in our study population.

Conclusion

The study indicates factors that are associated with deep tissue infections in the opioid use disorder population and can be used to identify opportunities to reduce the incidence of new infections.

Validity of International Classification of Diseases codes in identifying illicit drug use target conditions using medical record data as a reference standard: A systematic review

BACKGROUND

The twenty-first century opioid crisis has spurred interest in using International Classification of Diseases (ICD) code algorithms to identify patients using illicit drugs from administrative healthcare data. We conducted a systematic review of studies that validated ICD code algorithms for illicit drug use against a reference standard of medical record data.

METHODS

Systematic searches of MEDLINE, EMBASE, PsycINFO, and Web of Science were conducted for studies published between 1980 and 2018 in English, French, Italian, or Spanish. We included validation studies of ICD-9 or ICD-10 code algorithms for an illicit drug use target condition (e.g., illicit drug use, abuse, or dependence (UAD), illicit drug use-related complications) given the sensitivity or specificity was reported or could be calculated. Bias was assessed with the Quality Assessment of Diagnostic Accuracy Studies Version 2 (QUADAS-2) tool.

RESULTS

Six of the 1210 articles identified met the inclusion criteria. For validation studies of broad UAD (n = 4), the specificity was nearly perfect, but the sensitivity ranged from 47% to 83%, with higher sensitivities tending to occur in higher prevalence populations. For validation studies of injection drug use (IDU)-associated infective endocarditis (n = 2), sensitivity and specificity were poor due to the lack of an ICD code for IDU. For all six studies, the risk of bias for the QUADAS-2 "reference standard" and "flow/timing domains" was scored as "unclear" due to insufficient reporting.

CONCLUSIONS

Few studies have validated ICD code algorithms for illicit drug use target conditions, and available evidence is challenging to interpret due to inadequate reporting. PROSPERO Registration: CRD42019118401.

Methamphetamine Use and Its Correlates among Individuals with Opioid Use Disorder in a Midwestern U.S. City

Background: U.S. is experiencing a surging trend of methamphetamine use among individuals who use opioids. More research is needed to characterize this emerging "twin epidemic." Objectives: The study aims to identify social and behavioral characteristics associated with methamphetamine use among individuals with opioid use disorder (OUD) in the Dayton, Ohio, area, an epicenter of the opioid crisis and an emerging frontier of methamphetamine epidemic. Methods: 357 adult individuals with current OUD were recruited using targeted and respondent-driven sampling. Structured interviews collected information on social and drug use characteristics. Multivariable Logistic Regression was used to identify characteristics associated with the past 6-month use of methamphetamine. Results: 49.7% were female, and 88.8% were non-Hispanic whites. 55.6% used methamphetamine in the past 6-months, and 84.9% reported first use of methamphetamine after initiation of illicit opioids. Methamphetamine use was associated with homelessness (aOR = 2.46, p = .0001), lifetime history of diverted pharmaceutical stimulant use (aOR = 2.97, p < .001), injection route of heroin/fentanyl use (aOR = 1.89, p = .03), preference for fentanyl over heroin (aOR = 1.82, p = .048), lifetime history of extended-release injectable naltrexone (Vivitrol)-based treatment (aOR = 2.89, p = .003), and more frequent marijuana use (aOR = 1.26, p = .04). Discussion: The findings point to the complexity of motivational and behavioral pathways associated with methamphetamine and opioid co-use, ranging from self-treatment and substitution behaviors, attempts to endure homelessness, and greater risk taking to experience euphoria. More research is needed to understand the causal relationships and the association between methamphetamine and Vivitrol use. Public health responses to the opioid crisis need to be urgently expanded to address the growing epidemic of methamphetamine use.

The risk of infective endocarditis among people who inject drugs: a retrospective, population-based time series analysis

BACKGROUND

Infective endocarditis is an increasingly common complication among people who inject drugs. We conducted this study to determine whether the removal of traditional controlled-release oxycodone from the Canadian market would be associated with an increase in the use of hydromorphone and an increased risk of infective endocarditis.

METHODS

We conducted a retrospective, population-based time series analysis using the linked health administrative databases of Ontario, Canada. We measured the quarterly risk of admissions for infective endocarditis related to injection drug use and changes in opioid prescription rates from 2006 to 2015. We set the intervention point at the fourth quarter of 2011, when traditional controlled-release oxycodone was removed from the Canadian market.

RESULTS

We observed an increase in the risk of admissions for infective endocarditis related to injection drug use during the study period. Before the intervention point, we observed a mean of 13.4 admissions per quarter, and after the intervention, we observed a mean of 35.1 admissions per quarter. However, no significant change in this risk occurred at the intervention point. Rather, the risk of infectious endocarditis appeared to have increased earlier and in parallel with the rise in hydromorphone prescriptions. Hydromorphone represented 16% of all opioid prescriptions at the start of the observation period and 53% by the end.

INTERPRETATION

The risk of infective endocarditis related to injection drug use is increasing and is temporally associated with increasing prescriptions for hydromorphone. This relation warrants further exploration.

Management of endocarditis among persons who inject drugs: A narrative review of surgical and psychiatric approaches and controversies

BACKGROUND

People who inject drugs (PWID) represent a high-risk subgroup of endocarditis patients. This is highlighted by poorer post-operative outcomes in injection drug use-related infective endocarditis (IDU-IE), which is largely attributable to the increased vulnerability of prosthetic valves to re-infection. Consequently, many centres do not perform valve replacement on these patients. A parallel, but often underrecognized, component of care is the role of multidisciplinary management for individuals with IDU-IE, including perioperative addictions and psychiatric care. Consequently, surgical management options in IDU-IE remain a controversial topic.

OBJECTIVES

To determine the characteristics of optimal surgical and psychiatric care for individuals with IDU-IE.

METHODS

We conducted a narrative synthesis of the findings of literature retrieved from searches of computerized databases, hand searches, and authoritative text, organizing the findings into several key themes: clinical characteristics and factors associated with mortality in IDU-IE, alternative surgical management options, perioperative risk stratification techniques, principles of psychiatric and addictions management in IDU-IE, ethical considerations and controversies, and future research directions.

RESULTS/CONCLUSIONS

Managing IDU-IE involves the treatment of two comorbidities: the intra-cardiac infection and the underlying substance use disorder. Cardiac surgery represents a high-intensity intervention with appreciable risk, and the benefit it is not always clear. As patients often present acutely, it is not feasible to use drug abstinence as a prerequisite to surgery. Involvement of inpatient psychiatry and addictions teams, however, appears to be an evidence-based approach that can bridge IDU-IE patients with opioid agonist therapy in hospital and adequate outpatient treatment options for their underlying addiction upon their discharge from hospital. It is likely that a majority of these patients are not receiving optimal psychiatric management despite increasing recognition of efficacy. Further interdisciplinary studies are needed to elucidate optimal surgical and multidisciplinary protocols.

BACKGROUND

Infective endocarditis (IE) is an infection of the innermost lining of the heart often affecting the heart valves. Over the last few decades, the epidemiology of IE has shifted in the developed world and while it continues to be a significant cause of morbidity and mortality, there has been a significant increased incidence among persons who inject drugs (PWID). To date, well-conducted epidemiologic studies of IE among PWID have been sparse, which has limited our ability to fully characterize this disease phenomenon. To address this knowledge deficit, we conducted a narrative synthesis of the findings of literature retrieved from searches of computerized databases, hand searches, and authoritative text, and organized our findings into six key themes: clinical characteristics and factors associated with mortality in IDU-IE, alternative surgical management options, perioperative risk stratification techniques, principles of psychiatric and addictions management in IDU-IE, ethical considerations and controversies, and future research directions.

Infective Endocarditis in the Intravenous Drug Use Population at a Tertiary Hospital in Melbourne, Australia

BACKGROUND

Infective endocarditis has been associated with underlying cardiac pathology and streptococci infections. Intravenous drug use (IVDU) is increasingly implicated as a contributing factor, resulting in a shift to a younger patient demographic, tricuspid valve involvement, severe staphylococcal infection, and unique management challenges. The objective of this study was to describe the clinical features, management and outcomes of patients with IVDU-associated infective endocarditis in the Australian context.

METHODS

A retrospective review of all episodes of IVDU-associated infective endocarditis at a tertiary hospital in Melbourne, Australia, from 2008 to 2015, was conducted. Included cases met Duke Criteria for 'definite' or 'possible' infective endocarditis, and had a history of IVDU within 3 months of presentation. Demographic data, substance use history, clinical features, surgical intervention, follow-up, and mortality data was collected. We explored factors associated with surgical intervention, recurrence and mortality.

RESULTS

Fifty-five (55) episodes of IVDU-associated infective endocarditis were identified in 46 patients; the median age was 40 years and 58% were male. The tricuspid valve was most commonly affected (38%), and left heart pathology was documented in 53% of cases. Methicillin-sensitive Staphylococcus aureus was the most common pathogen (67%). Thirty-six (36%) per cent of patients underwent surgical intervention, and all patients received antibiotics as a component of treatment, with a median duration of 42 days (IQR 21, 42 days). Heart failure and a vegetation larger than 1 cm were significantly associated with surgical intervention. Total mortality was 14.5%; surgical mortality was 10%. Opioid replacement therapy and the absence of psychiatric co-morbidities were protective factors for surgical intervention and disease recurrence.

CONCLUSIONS

In contrast to common perception, left-sided endocarditis was more common than tricuspid valve endocarditis. Left heart pathology is typically a more severe clinical entity, however, our study determined mortality rates remained similar when compared to right heart pathology. Further research is required to assess rates of left sided disease in the IVDU population, and elucidate the relationship between IVDU and left heart pathology.

Rising rates of injection drug use associated infective endocarditis in Virginia with missed opportunities for addiction treatment referral: a retrospective cohort study

BACKGROUND

Injection drug use (IDU) is a growing public health threat in Virginia, though there is limited knowledge of related morbidity. The purpose of this study was to describe the temporal, geographic and clinical trends and characteristics of infective endocarditis associated with IDU (IDU-IE) and to identify opportunities for better-quality care of people who inject drugs (PWID).

METHODS

We reviewed charts for all admissions coded for both IE and drug use disorders at the University of Virginia Medical Center (UVA) from January 2000 to July 2016. A random sample of 30 admissions coded for IE per year were reviewed to evaluate temporal trends in the proportion of IDU associated IE cases.

RESULTS

There were a total of 76 patients with IDU-IE during the study period, 7.54-fold increase (prevalence ratio: 8.54, 95% CI 3.70-19.72) from 2000 to 2016. The proportion of IE that was IDU-associated increased by nearly 10% each year (prevalence ratio of IDU per year: 1.09, 95% CI: 1.05-1.14). Patients with IDU-IE had longer hospital stays [median days (interquartile range); IDU-IE, 17 (10-29); non-IDU-IE, 10 (6-18); p-value = 0.001] with almost twice the cost of admission as those without IDU [median (interquartile range); IDU-IE, $47,899 ($24,578-78,144); non-IDU-IE, $26,460 ($10,220-60,059); p-value = 0.001]. In 52% of cases there was no documentation of any discussion regarding addiction treatment.

CONCLUSION

IDU-IE is a severe infection that leads to significant morbidity and healthcare related costs. IDU-IE rates are increasing and will likely continue to do so without targeted interventions to help PWID. The diagnosis and treatment of IDU-IE provides an opportunity for the delivery of addiction treatment, counseling, and harm reduction strategies.