Evolving epidemiology of injecting drug use-associated infective endocarditis: A regional centre experience

Allostatic load in opioid use disorder: a scoping review protocol

INTRODUCTION

Opioid use disorder affects 2.1 million individuals in the USA, causing more than 100 000 overdose-related deaths annually. While the neurobiological model of addiction is well described and accepted, there is a lack of morbidity and mortality prognosticators for patients struggling with opioid use disorder. Allostatic load index is a promising candidate for the basis of a prognostication tool. Previous studies show that allostatic load predicts both morbidity and mortality in a variety of cohorts. This scoping review protocol provides the rationale and steps for summarising and presenting existing evidence surrounding allostatic load in the context of opioid use disorder. Identification of current knowledge gaps will pave the way for subsequent prospective studies.

METHODS AND ANALYSIS

This scoping review protocol will follow the five-step method designed by Arksey and O'Malley. All studies written in English on allostatic load in the context of opioid use disorder, as defined in our inclusion criteria, will be included. There will be no limit on the year of publication. We will search PubMed, Embase, CINAHL, PsycINFO and Google Scholar. We will hand-review reference lists of included articles, and we will hand search grey literature. We will then group, analyse and present the data in narrative, tabular and diagrammatic format according to themes identified in the scoping review.

ETHICS AND DISSEMINATION

Ethics approval is not necessary, as data are gathered from publicly accessible sources. The results will be disseminated through a peer-reviewed journal and reported at conferences related to addiction medicine.

TRIAL REGISTRATION NUMBER

10.17605/OSF.IO/4J6DQ.

The Economic Burden of Infective Endocarditis due to Injection Drug Use in Australia: A Single Centre Study-University Hospital Geelong, Barwon Health, Victoria

Background

Injection drug use (IDU) is a well-recognized risk factor for infective endocarditis (IE). Associated complications from IDU result in significant morbidity and mortality with substantial cost implications. The aim of this study was to determine the cost burden associated with the management of IE due to IDU (IE-IDU).

Methods

We used data collected prospectively on patients with a diagnosis of IE-IDU as part of the international collaboration on endocarditis (ICE). The cost of medical treatment was estimated based on diagnosis-related groups (DRG) and weighted inlier equivalent separation (WIES).

Results

There were 23 episodes from 21 patients in 12 years (2002 to 2014). The costing was done for 22 episodes due to data missing on 1 patient. The median age was 39 years. The gender distribution was equal. Heroin (71%) and methamphetamine (33%) were the most frequently used. 74% (17/23) required intensive care unit (ICU) admission. The median ICU length of stay (LOS) was 4 days (IQR (Interquartile range); 2 to 40 days) whilst median total hospital LOS was 40 days (IQR; 1 to 119 days). Twelve patients (52%) underwent valve replacement surgery. Mortality was 13% (3/23). The total medical cost for the 22 episodes is estimated at $1,628,359 Australian dollars (AUD). The median cost per episode was a median cost of $ 61363 AUD (IQR: $2806 to $266,357 AUD). We did not account for lost productivity and collateral costs attributed to concurrent morbidity.

Conclusion

Within the limitations of this small retrospective study, we report that the management of infective endocarditis caused by injection drug use can be associated with significant financial cost.

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.

Recent trends in infective endocarditis among patients with and without injection drug use: An eight-year single center study

BACKGROUND

Infective endocarditis (IE) is associated with considerable morbidity and mortality. Given the opioid crisis and emergence of drug-resistant organisms, we sought to examine annual trends in hospitalization rates for IE and potential epidemiologic shift in the causative microorganisms among patients with and without injection drug use (IDU).

METHODS

This was a single-center retrospective cohort study of hospitalized adults with IE. Annual trends in hospitalization rates were calculated (2011-2018), and patient characteristics and clinical outcomes were compared according to IDU status.

RESULTS

Our cohort of 244 hospitalized patients with IE had a subset of 112 with IDU. The annual hospitalization rate for IE increased almost four-fold and was most notable among patients with IDU. The highest increase occurred in patients with Staphylococcus aureus-associated IE. Patients with IDU were younger, and more likely to be women with tricuspid valve vegetations and have IE due to methicillin-sensitive and methicillin-resistant Staphylococcus aureus. Patients without IDU were more likely to have central venous catheters with mitral and aortic valve vegetations and have IE due to Streptococcus and coagulase-negative Staphylococcus species. Patients without IDU had a higher requirement for cardiac surgery and higher 90-day mortality. Age was the only independent variable associated with 90-day mortality.

CONCLUSIONS

The rising incidence of IE in younger and older persons is driven in part by the opioid public health crisis and higher prevalence of indwelling central venous catheters, respectively. Timely treatment of opioid use disorders and stewardship surrounding use of central venous catheters is urgently needed.

Burden of infective endocarditis in an Australian cohort of people who inject drugs

BACKGROUND

Infective endocarditis (IE) results in substantial morbidity and mortality in people who inject drugs (PWID).

AIMS

To describe the burden of IE and its outcomes in PWID.

METHODS

Retrospective cohort study of adults admitted to a tertiary referral centre in Melbourne, Australia, with IE due to injection drug use from 1997 to 2015.

RESULTS

Ninety-seven PWID with 127 episodes of IE were identified with a median acute inpatient stay of 37 days (1-84). Admission to an intensive care unit was required in 67/127 (53%) episodes. Twenty-seven percent (34/127) of episodes occurred in patients with a previous episode of endocarditis. One third (43/127, 34%) of episodes involved left-sided cardiac valves. Antimicrobial treatment was completed in 88 (70%) episodes. Valve surgery was performed in 25/127 (20%) episodes. Predictors of surgery in univariable analysis were left-sided cardiac involvement (risk ratio (RR) 6.0), severe valvular regurgitation (RR 2.6) and cardiac failure (RR 2.2) (all P < 0.005). Twenty (16%) episodes resulted in death. Predictors of mortality on univariable analysis were left-sided cardiac involvement (RR 6.4), and not completing treatment (RR 0.12; both P < 0.001). The average estimated cost per episode was AU$74 168.

CONCLUSIONS

IE causes a considerable burden of disease in PWID, with significant healthcare utilisation and cost. Surgery and death are not infrequent complications. In addition to ensuring completion of antimicrobial therapy, strategies such as opioid maintenance programmes may be useful in improving health outcomes for PWID.

Opioid-Associated Out-of-Hospital Cardiac Arrest: Distinctive Clinical Features and Implications for Health Care and Public Responses: A Scientific Statement From the American Heart Association

Opioid overdose is the leading cause of death for Americans 25 to 64 years of age, and opioid use disorder affects >2 million Americans. The epidemiology of opioid-associated out-of-hospital cardiac arrest in the United States is changing rapidly, with exponential increases in death resulting from synthetic opioids and linear increases in heroin deaths more than offsetting modest reductions in deaths from prescription opioids. The pathophysiology of polysubstance toxidromes involving opioids, asphyxial death, and prolonged hypoxemia leading to global ischemia (cardiac arrest) differs from that of sudden cardiac arrest. People who use opioids may also develop bacteremia, central nervous system vasculitis and leukoencephalopathy, torsades de pointes, pulmonary vasculopathy, and pulmonary edema. Emergency management of opioid poisoning requires recognition by the lay public or emergency dispatchers, prompt emergency response, and effective ventilation coupled to compressions in the setting of opioid-associated out-of-hospital cardiac arrest. Effective ventilation is challenging to teach, whereas naloxone, an opioid antagonist, can be administered by emergency medical personnel, trained laypeople, and the general public with dispatcher instruction to prevent cardiac arrest. Opioid education and naloxone distributions programs have been developed to teach people who are likely to encounter a person with opioid poisoning how to administer naloxone, deliver high-quality compressions, and perform rescue breathing. Current American Heart Association recommendations call for laypeople and others who cannot reliably establish the presence of a pulse to initiate cardiopulmonary resuscitation in any individual who is unconscious and not breathing normally; if opioid overdose is suspected, naloxone should also be administered. Secondary prevention, including counseling, opioid overdose education with take-home naloxone, and medication for opioid use disorder, is important to prevent recurrent opioid overdose.

Prospective Cohort Study of Infective Endocarditis in People Who Inject Drugs

BACKGROUND

Infective endocarditis (IE) in people who inject drugs (PWID) is an emergent public health problem.

OBJECTIVES

The purpose of this study was to investigate IE in PWID and compare it with IE in non-PWID patients.

METHODS

Two prospective cohort studies (ICE-PCS and ICE-Plus databases, encompassing 8,112 IE episodes from 2000 to 2006 and 2008 to 2012, with 64 and 34 sites and 28 and 18 countries, respectively). Outcomes were compared between PWID and non-PWID patients with IE. Logistic regression analyses were performed to investigate risk factors for 6-month mortality and relapses amongst PWID.

RESULTS

A total of 7,616 patients (591 PWID and 7,025 non-PWID) were included. PWID patients were significantly younger (median 37.0 years [interquartile range: 29.5 to 44.2 years] vs. 63.3 years [interquartile range: 49.3 to 74.0 years]; p < 0.001), male (72.5% vs. 67.4%; p = 0.007), and presented lower rates of comorbidities except for human immunodeficiency virus, liver disease, and higher rates of prior IE. Amongst IE cases in PWID, 313 (53%) episodes involved left-side valves and 204 (34.5%) were purely left-sided IE. PWID presented a larger proportion of native IE (90.2% vs. 64.4%; p < 0.001), whereas prosthetic-IE and cardiovascular implantable electronic device-IE were more frequent in non-PWID (9.3% vs. 27.0% and 0.5% vs. 8.6%; both p < 0.001). Staphylococcus aureus caused 65.9% and 26.8% of cases in PWID and non-PWID, respectively (p < 0.001). PWID presented higher rates of systemic emboli (51.1% vs. 22.5%; p < 0.001) and persistent bacteremia (14.7% vs. 9.3%; p < 0.001). Cardiac surgery was less frequently performed (39.5% vs. 47.8%; p < 0.001), and in-hospital and 6-month mortality were lower in PWID (10.8% vs. 18.2% and 14.4% vs. 22.2%; both p < 0.001), whereas relapses were more frequent in PWID (9.5% vs. 2.8%; p < 0.001). Prior IE, left-sided IE, polymicrobial etiology, intracardiac complications, and stroke were risk factors for 6-month mortality, whereas cardiac surgery was associated with lower mortality in the PWID population.

CONCLUSIONS

A notable proportion of cases in PWID involve left-sided valves, prosthetic valves, or are caused by microorganisms other than S. aureus.

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.

Reasons for assisting with injection initiation: Results from a large survey of people who inject drugs in Los Angeles and San Francisco, California

Injection drug initiation usually requires assistance by someone who already injects drugs. To develop interventions that prevent people from starting to inject drugs, it is imperative to understand why people who inject drugs (PWID) assist with injection initiation.

METHODS

Injection initiation history and motives for initiating others were collected from 978 PWID in Los Angeles and San Francisco, CA, from 2016-17. This article documents motivations for providing injection initiation assistance and examines demographic, economic, and health-related factors associated with these motivations using multivariable logistic regression modeling.

RESULTS

Among the 405 PWID who ever facilitated injection initiation, motivations for initiating were: injury prevention (66%), skilled at injecting others (65%), to avoid being pestered (41%), in exchange for drugs/money (45%), and for food/shelter/transportation (15%). High frequency initiation (>5 lifetime injection initiations) was associated with all motivations except for being pestered. Initiation to prevent injury was associated with being female. Initiation due to pestering was associated with recycling income and sex work. Being skilled was associated with age and HIV status, while initiation for money or drugs was associated with age, race, education, social security income, and substance use treatment. Lastly, initiation for food, shelter, or transportation was associated with age, sexual orientation and education level.

CONCLUSION

Diverse factors were associated with reported motivations for assisting someone to initiate injection for the first time. Our analysis underscores the need for prevention strategies focused on improving economic and housing conditions along with implementing drug consumption rooms to disrupt the social processes of injection initiation.

Hydromorphone and the risk of infective endocarditis among people who inject drugs: a population-based, retrospective cohort study

BACKGROUND

The incidence of infective endocarditis related to injection drug use is increasing. On the basis of clinical practice and epidemiological and in-vitro data, we postulated that exposure to controlled-release hydromorphone is associated with an increased risk of infective endocarditis among people who inject drugs.

METHODS

We used linked health administrative databases in Ontario, Canada, to assemble a retrospective cohort of adults (aged 18-55 years) who inject drugs for the period of April 1, 2006, to Sept 30, 2015. Cases of infective endocarditis among this cohort were identified using International Classification of Diseases 10 codes. We estimated exposure to hydromorphone and risk of infective endocarditis among this cohort in two ways. First, in a population-level analysis, we identified patients living in regions with high (≥25%) and low (≤15%) hydromorphone prescription rates and, after matching 1:1 on various baseline characteristics, compared their frequency of infective endocarditis. Second, in a patient-level analysis including only those with prescription drug data, we identified those who had filled prescriptions (ie, received the drug from the pharmacy) for controlled-release or immediate-release hydromorphone and, after matching 1:1 on various baseline characteristics, compared their frequency of infective endocarditis with that of patients who had filled prescriptions for other opioids.

RESULTS

Between April 1, 2006, and Sept 30, 2015, 60 529 patients had evidence of injection drug use, 733 (1·2%, 95% CI 1·1-1·3) of whom had infective endocarditis. In the population-level analysis of 32 576 matched patients, we identified 254 (1·6%) admissions with infective endocarditis in regions with high hydromorphone use and 113 (0·7%) admissions in regions with low use (adjusted odds ratio [OR] 2·2, 95% CI 1·8-2·8, p<0·0001). In the patient-level analysis of 3884 matched patients, the frequency of infective endocarditis was higher among patients who filled prescriptions for hydromorphone than among those who filled prescriptions for non-hydromorphone opioids (2·8% [109 patients] vs 1·1% [41 patients]; adjusted OR 2·5, 95% CI 1·8-3·7, p<0·0001). This significant association was seen for controlled-release hydromorphone (3·9% [73 of 1895 patients] vs 1·1% [20 of 1895]; adjusted OR 3·3, 95% CI 2·1-5·6, p<0·0001), but not for immediate-release hydromorphone (1·8% [36 of 1989] vs 1·1% [21 of 1989]; 1·7, 0·9-3·6, p=0·072.

INTERPRETATION

Among people who inject drugs, the risk of infective endocarditis is significantly higher for those exposed to controlled-release hydromorphone than to other opioids. This association might be mediated by the controlled-release mechanism and should be the subject of further investigation.

FUNDING

Ontario Ministry of Health and Long-Term Care, Academic Medical Organization of Southwestern Ontario, Schulich School of Medicine and Dentistry (Western University), and Lawson Health Research Institute.

A changing profile of infective endocarditis at a tertiary hospital in China: a retrospective study from 2001 to 2018

Background

Infective endocarditis (IE) is a lethal disease which has been changing significantly over the past decades; however, information about IE in China remains scarce. This study surveyed the changes in clinical characteristics of IE at a tertiary hospital in south China over a period of nearly 18 years.

Methods

Medical records with IE patients consecutively hospitalized between June 2001 and June 2018 were selected from the electronic medical records system in Nanfang Hospital of Southern Medical University. Data were divided by admission time into two groups equally: early-period group, June 2001 to December 2009 and later-period group, January 2010 to July 2018.

Results

A Total of 313 IE patients were included in our study. Compared with the early-period group, patients in the later-period group included fewer intravenous drug users (IVDUs), older age at onset, reduced development of pulmonary embolism, less renal dysfunction, decreased proportion of Staphylococcus aureus infection and fewer vegetations observed in the right heart by echocardiography. The later-period group also showed a higher proportion of ischemic strokes and higher proportion of positive microbiological findings compared with the early-period group. The in-hospital mortality remained about the same between the two periods and the multivariate analysis identified intravenous drug addicted, prosthetic valve endocarditis, hemorrhagic stroke, acute congestive heart failure, renal insufficiency, left-sided endocarditis, early surgical as independent predictors of in-hospital mortality.

Conclusions

Our study demonstrated a dramatic change in the profile of IE over a period of 18 years at a tertiary hospital in south China and presented several independent predictors of in-hospital mortality. The geographic variations observed in our study will be of important value to profile the clinical feature of China and offer the reference for clinical decisions in our region.

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.

Validation of an Algorithm to Identify Infective Endocarditis in People Who Inject Drugs

INTRODUCTION

Infective endocarditis is associated with high morbidity and mortality. Currently, there is concern that the incidence of infective endocarditis associated with people who inject drugs (PWID) is increasing. However, it is difficult to monitor population-wide trends in PWID-associated infective endocarditis, as there is no International Statistical Classification of Diseases, 10th Revision (ICD-10) code for injection drug use. To address this barrier, we sought to develop a validated algorithm using ICD-10 discharge diagnosis codes.

MATERIALS AND METHODS

We constructed a cohort of patients whose hospital discharge diagnosis included infective endocarditis. We reviewed 100 patients with incident infective endocarditis from 2014 to 2016 for their infective endocarditis and injection drug use status. We calculated the operating characteristics for algorithms constructed using permutations of ICD-10 codes associated with injection drug use. We repeated this analysis in a cohort of 100 patients with incident infective endocarditis from 2009 to 2011 to examine the temporal stability of the operating characteristics of each algorithm.

RESULTS

We found that a combination of hepatitis C virus, drug use, and mental/behavioral disorder codes yielded the highest sensitivity (93%) and positive predictive value (83%) of the algorithms analyzed.

DISCUSSION

We have described the first algorithm, validated against chart review data, for identifying PWID-associated infective endocarditis cases using ICD-10 codes. The high sensitivity and positive predictive value indicate that this algorithm can be used for surveillance and research with confidence.

CONCLUSIONS

This algorithm will enable researchers to examine epidemiological trends in PWID-associated infective endocarditis.

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.

Repeat Infective Endocarditis in Persons Who Inject Drugs: "Take Another Little Piece of my Heart"

Background

Injection drug use (IDU) is a major risk factor for infective endocarditis (IE). Few data exist on repeat IE (rIE) in persons who inject drugs (PWID).

Methods

Patients ≥18 years old seen at Wake Forest Baptist Medical Center from 2004 to 2017 who met Duke criteria for IE and who self-reported IDU in the 3 months before admission were identified. The subset of PWID who developed rIE, defined as another episode of IE at least 10 weeks after diagnosis of the first episode, was then reviewed.

Results

Of the 87 PWID who survived their first episode of IE, 22 (25.3%) experienced rIE and 77.3% had rIE within a year of the first episode. All patients who experienced rIE resumed IDU between episodes of IE. Of the patients with rIE, 54.5% had an infection caused by S. aureus and 22.7% required surgical intervention. Mortality at 1 year was 36.3%. Compared with their first IE episode, patients with rIE had fewer S. aureus infections (P = .01). Compared with PWID who experienced single-episode IE, intravenous prescription opioid use (P = .01), surgery (P < .01), tricuspid valve involvement (P = .02), and polymicrobial infection (P = .03) occurred more often during first episodes of IE in individuals who then developed rIE.

Conclusions

rIE is common among IDU-related IE and confers a high 1-year mortality rate. The microbiology of rIE is varied, with S. aureus being less frequently isolated. More studies on modification of social and clinical risk factors are needed to prevent rIE.

Clinical Characteristics and Factors Associated With Mortality in First-Episode Infective Endocarditis Among Persons Who Inject Drugs

IMPORTANCE

Persons who inject drugs (PWID) represent a distinct demographic of patients with infective endocarditis. Many centers do not perform valvular surgery on these patients owing to concerns about poor outcomes. Addiction services are underused in hospitals.

OBJECTIVES

To compare clinical characteristics in first-episode infective endocarditis in PWID who are surgically vs medically managed and to identify variables associated with mortality.

DESIGN, SETTING, AND PARTICIPANTS

This case series studied PWID treated for a first episode of infective endocarditis between April 1, 2007, and March 30, 2016. Participants were adult patients (aged ≥18 years) admitted to any of 3 hospitals in London, Ontario, Canada. Analysis occurred between July 2016 and November 2017.

MAIN OUTCOMES AND MEASURES

Survival among PWID; the causative organisms, site of infection, and cardiac as well as noncardiac complications; referral to addiction services; and surgical vs medical management.

RESULTS

Of 370 total first-episode cases of infective endocarditis, 202 (54.6%) were in PWID. Among PWID, 105 (52%) were male, the median (interquartile range) age was 34 (28-42) years, and patients were predominantly positive for the hepatitis C virus (69.8% [141 of 202]). Right-sided infection was more common (61.4% [124 of 202]), and most infections were caused by Staphylococcus aureus (77.2% [156 of 202]). Surgery occurred in 19.3% of patients (39 of 202). The all-cause mortality rate was 33.7% (68 of 202). Adjusting for age and sex, survival analysis demonstrated that surgery was associated with lower mortality (hazard ratio [HR], 0.44; 95% CI, 0.23-0.84; P = .01), as was referral to addiction treatment (HR, 0.29; 95% CI, 0.12-0.73; P = .008). Higher mortality was associated with left-sided infection (HR, 3.26; 95% CI, 1.82-5.84; P < .001) and bilateral involvement (HR, 4.51; 95% CI, 2.01-10.1; P < .001).

CONCLUSIONS AND RELEVANCE

This study presents the demographic characteristics of first-episode infective endocarditis in PWID. Results highlight the potentially important role of addictions treatment in this population. Further study to optimize selection criteria for surgery in PWID is warranted.

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.

Association between route of illicit drug administration and hospitalizations for infective endocarditis

Objective

This study examined the association between the route of drug administration and being hospitalized for infective endocarditis among 4817 treatment-seeking illicit drug users in Finland.

Methods

Cox regression models were used to examine the association between the route of drug administration and infective endocarditis hospitalization, adjusted for age, gender, and homelessness. Cases of infective endocarditis as a primary/main diagnosis were tracked using the 10th version of the International Classification of Disease code I33.

Results

In all, 47 persons had a primary diagnosis of infective endocarditis. These 47 persons contributed a total of 95 hospitalizations and their total length of hospital stay was 1393 days. There was a statistically significant difference in hospitalizations between injectors and non-injectors (Log-Rank test p = 0.018). Univariate Cox model showed that injectors had higher hazard or risk for infective endocarditis hospitalization compared to non-injectors (hazard ratio: 2.04, 95% confidence interval: 1.12-3.73, p = 0.020). After adjusting for age, gender, and homelessness in the multivariate model, the elevated hazard among injectors compared to non-injectors remained statistically significant with adjusted hazard ratio of 2.12 (95% confidence interval: 1.11-4.07, p = 0.024).

Conclusion

The study findings suggested a need to boost harm reduction measures targeting high-risk injecting and other health behaviors among injecting drug users in order to reduce their hospitalizations for infective endocarditis.

Staphylococcus aureus bacteraemia and endocarditis - epidemiology and outcome: a review

PURPOSE

To review the epidemiology of Staphylococcus aureus bacteraemia (SAB) and endocarditis (SAE), and discuss the short- and long-term outcome.  Materials and methods: A literature review of the epidemiology of SAB and SAE.

RESULTS

The reported incidence of SAB in Western countries is 16-41/100,000 person-years. Increasing incidence has been observed in many regions, in Iceland by 27% during 1995-2008. The increase is believed to depend on changes in population risk factors and possibly better and more frequent utilization of diagnostic procedures. S. aureus is now the leading causes of infective endocarditis (IE) in many regions of the world. It accounts for 15-40% of all IE cases, and the majority of cases in people who inject drugs (PWID). Recently, the incidence of SAE in PWID in Stockholm, Sweden, was found to be 2.5/1000 person-years, with an in-hospital mortality of 2.5% in PWID as compared to 15% in non-drug users. The 30-day mortality associated with SAB amounts to 15-25% among adults in Western countries, but is lower in children (0-9%). Mortality associated with SAE is high (generally 20-30% in-hospital mortality), and symptomatic cerebral embolizations are common (12-35%). The 1-year mortality reported after SAB and SAE is 19-62% and reflects deaths from underlying diseases and complications caused by the infection. In a subset of SAE cases, valvular heart surgery is needed (15-45%), but active intravenous drug use seems to be a reason to refrain from surgery. Despite its importance, there are insufficient data on the optimal management of SAB and SAE, especially on the required duration of antibiotic therapy.  Conclusions: The epidemiology of SAB and SAE has been changing in the past decades. They still carry a substantial morbidity and mortality. Intensified studies on treatment are warranted for improving patient outcome.

Risk and outcomes of aortic valve endocarditis among patients with bicuspid and tricuspid aortic valves

Objective

Patients with structural abnormalities of cardiac valves, including bicuspid aortic valve (BAV), are said to be at higher risk of infective endocarditis (IE). We sought to determine the risk of IE of the BAV compared with the tricuspid aortic valve (TAV) and to determine the risk of aortic valve replacement and mortality after IE.

Methods

From medical records of two US and one Italian hospitals, patients with their first episode of IE of any native valve were identified. In the US cohort 42 patients with BAV and 393 patients with TAV with IE occurring between 1 January 2000 and 30 June 2014 were identified. In the Italian cohort 48 patients with BAV and 341 patients with TAV with IE underwent valve replacement surgery between 1 January 2000 and1 November 2015. The risk of IE for BAV and TAV and subsequent outcomes were determined after matching to patients without IE.

Results

After adjustment for risk factors, the risk of IE in the US cohort was 23.1 (95% CI 8.1 to 100, p <0.0001) times greater for BAV than TAV. Patients with BAV with IE were more likely to have an aortic root abscess. Within the subsequent 5 years, BAV patients with IE were more likely to undergo valve replacement (85%) than TAV patients with IE (46%). Patients with IE were at increased risk of death. The findings were similar in the Italian cohort.

Conclusions

Patients with BAV are at markedly increased risk of IE and aortic root abscess than patients with TAV. Increased risk of IE in patients with BAV indicates they may be a candidate group for long-term trials of antibiotic prophylaxis of IE.

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

BACKGROUND

Infective endocarditis (IE) is associated with significant mortality and morbidity despite recent advances in management. Injecting drug use (IDU) remains an important risk factor. Our aim was to evaluate the rates and patient demographics of IE and injecting drug use-associated infective endocarditis (IDU-IE) in Victoria from 2009 to 2014.

METHODS

The Victorian Admitted Episode Dataset (VAED) was used to identify a population-based cohort with a diagnosis of IE and IDU-IE between 2009 and 2014 in Victoria. Incidence rates were calculated per 100,000 people/year. Rate ratios were calculated using Poisson distributions, and chi squared (χ²) test for trend were calculated to identify significant linear trends.

RESULTS

The incidence rate of IE overall has risen significantly from 11.09 to 13.56 per 100,000 people/year from 2009 to 2014 (rate ratio 1.22, 95% confidence interval (CI) 1.10, 1.36, p<0.001). The incidence of IDU-IE has also risen significantly from 0.92 to 1.76 per 100,000 people/year from 2009 to 2014 (rate ratio 1.93, 95% CI 1.28, 2.90, p=0.002). The chi squared (χ²) test for trend of both IE and IDU-IE also suggests a statistically significant linear trend (p=0.0015 and 0.005 respectively). Descriptive epidemiology revealed men are twice as likely to be affected by IE overall. The elderly were found to be the most affected by IE overall (ages 75 to 79 years) with IDU-IE affecting a much younger age group (ages 30 to 34 years). Validation of hospital coding for IDU-IE was shown to have sensitivity of 77.2% (95% CI 64.8, 86.2).

CONCLUSIONS

This study identified that from 2009 to 2014 there has been a significant increase in incidence of both IE overall and IDU-IE in Victoria. These findings highlight the need for the planning of targeted interventions to mitigate the incidence of disease.

Low mortality but increasing incidence of Staphylococcus aureus endocarditis in people who inject drugs: Experience from a Swedish referral hospital

Staphylococcus aureus is a leading cause of infective endocarditis in people who inject drugs (PWID). The management of S aureus endocarditis (SAE) in PWID can be problematic. The objective of this retrospective observational study was to assess the epidemiology, clinical characteristics, and mortality of S aureus endocarditis (SAE) in PWID in Stockholm, Sweden.The Department of Infectious Diseases at the Karolinska University Hospital serves as a regional referral center for drug users with severe infections. Patients with active intravenous drug use treated for SAE at the department between January 2004 and December 2013 were retrospectively identified. Clinical and microbiological data were obtained from medical records and the diagnosis verified according to the modified Duke criteria.In total, 120 SAE episodes related to intravenous drug use were identified. Its incidence in Stockholm was 0.76/100,000 adult person-years for the entire period, increasing from 0.52/100,000 person-years in 2004 to 2008 to 0.99 in 2009 to 2013 (P = 0.02). The SAE incidence among PWID specifically was 249 (range 153-649) /100,000 person-years. Forty-two (35%) episodes were left-sided, and multiple valves were involved in 26 (22%). Cardiac valve surgery was performed in 10 (8%) episodes, all left-sided. The in-hospital and 1-year mortality rates were 2.5% (3 deaths) and 8.0% (9 deaths), respectively.We noted a high and increasing incidence over time of SAE related to intravenous drug use in Stockholm. The increased incidence partly reflects a rising number of PWID during the study period. The low mortality noted, despite a substantial proportion with left-sided endocarditis, probably in part reflects the quality of care obtained at a large and specialized referral center for drug users with severe infections.

Infective endocarditis caused by Klebsiella oxytoca in an intravenous drug user with cancer

Infective endocarditis caused by Klebsiella species is rare, with most isolates being K. pneumoniae. We report the case of a 24-year-old intravenous drug user with newly diagnosed seminoma who developed K. oxytoca endocarditis. In addition to having K. oxytoca isolated from blood culture, cultures of that species were obtained from a retroperitoneal metastasis found on original presentation.

Cardiac surgery for infective endocarditis in patients with intravenous drug use

OBJECTIVES

Intravenous drug users have a high risk of infective endocarditis and reduced survival. Cardiac surgery may be recommended for these patients, but redo surgery is controversial. This study describes the characteristics and outcomes of intravenous drug users accepted for surgery during a 12-year period.

METHODS

This retrospective study included 29 injecting drug users treated with valve surgery for endocarditis between January 2001 and December 2013 at a tertiary academic centre. Survival was assessed by Kaplan-Meier analysis.

RESULTS

The median patient age was 36 (24-63) years and 27 patients (93%) were male. Staphylococcus aureus (52%) and Enterococcus faecalis (17%) were the most common microorganisms. Common illicit drugs were opioids (69%), amphetamines (52%) and benzodiazepines (24%). Mixed abuse was reported in 66% of patients. Seven patients (24%) had prior intracardial implants or native valve pathology. Twenty-five patients (86%) were positive for hepatitis C virus antibody, but none carried the human immunodeficiency virus. Twelve (41%) were homeless and 15 (52%) had poor dental hygiene. Three patients (10%) received medication-assisted rehabilitation before surgery. The main indications for surgery were regurgitation and secondary heart failure (86%), embolization (41%) and uncontrolled infection (24%). Aortic valve replacement was performed in 24 patients (83%), either as part of univalvular or multiple valve surgery. Seven patients (24%) had multivalvular endocarditis. All but 3 patients received biological valve prostheses. The 30-day mortality was 7% after first time surgery. During follow-up, 15 patients (52%) presented with reinfection: 10 (35%) were offered a second and 2 (7%) a third operation. Thirty-day mortality was 10% after redo surgery. Thirteen patients (45%) died within a median of 22 (0-84) months. Continued intravenous drug use was reported in 70 and 44% of patients after the first and second operation, respectively.

CONCLUSIONS

Cardiac surgery for infective endocarditis has acceptable early postoperative results among intravenous drug users. The 2- and 5-year survival were 79 and 59%, respectively. The number of reinfections was high within 2 years, as continued drug use seems to be a major challenge for this group.

Injection of Pharmaceuticals Designed for Oral Use: Harms Experienced and Effective Harm Reduction Through Filtration

Several pharmaceutical products are liable to 'abuse' or use outside their prescription, which frequently involves their injection. Examples are slow-release forms of morphine and oxycodone, and sublingual buprenorphine. During injection preparation, the drug is extracted into water, after crushing and heating the tablet if considered necessary. Since these products are designed for oral administration, they can contain excipients (ingredients other than the drug) which are poorly soluble, resulting in suspension of particles in the injection solution. Injected particles are able to produce medical complications such as the blockage of small blood vessels leading to ischaemia (inadequate blood flow) and tissue damage. Filtration can be used to remove particles from the suspension; including bacteria if the porosity is small enough (0.2 μm). However, filters are liable to blockage when overloaded, especially if the pore size is small. This problem can be minimised by using a larger pore size (e.g. 5-10 μm), but the resulting filtrate will contain many residual small particles. The use of two filters, coarse and fine, either sequentially or in a double membrane device, enables removal of the majority of particles as well as bacteria, although not quite meeting pharmaceutical standards for safe injection. Although not yet evaluated by a clinical trial, this highly effective filtration process would be expected to greatly reduce the risk of vascular and related complications, as well as non-viral infections. Careful technique ensures that drug is not lost by filtration, a priority for most drug consumers. Practical issues that affect acceptability of filtration by injecting drug users, including ease of use and cost, will need to be considered. However, given the laboratory evidence demonstrating the effectiveness of filters it is time to consider these tools as essential for safe injection as sterile needles/syringes for the world's approximately 16 million people who inject drugs.