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

Hospital admission costs of acute injection-related infections among people who inject drugs

INTRODUCTION

There are limited existing data regarding the financial costs associated with hospitalisation for injection-related infection (IRI) in Australia. We aimed to estimate the cost, from the healthcare funder perspective, of admissions to treat IRI.

METHODS

We performed a retrospective audit of 226 admissions with an IRI at the Alfred Hospital (Melbourne, Australia), from January 2017 to April 2019. Eligibility criteria included admission for management of an IRI and current injecting drug use, defined as self-reported injecting drug use within the preceding 6 months, documented in the medical record. We estimated the cost of each hospital admission, using national hospital price weights that accounted for the Australian Refined Diagnosis Related Groups and length of stay.

RESULTS

Among admissions with IRI, the median (interquartile range; IQR) cost of admissions with uncomplicated skin and soft tissue infection and complicated infection were AU$8416 (IQR $4132-$8611) and AU$31,938 (IQR $14,301-$54,397), respectively. Admissions requiring intensive care or surgery were associated with higher costs. The most expensive infection based on hospital cost was spinal infections (median AU$58,366 [IQR 31,938-$69,001]), despite endocarditis having higher median length of stay (38 days [IQR 18-46] vs. 24 [15-32]).

DISCUSSION AND CONCLUSIONS

We demonstrate the costs associated with hospital admissions for IRI, including the substantial increased costs associated with complicated IRI. This highlights the opportunity for cost savings associated with harm minimisation interventions to avoid infections and their sequelae.

Assessment of harm reduction receipt and infectious diseases outcomes in United States Veterans with opioid use disorder and history of injection drug use

BACKGROUND

Injection drug use (IDU) may lead to negative health outcomes and increased healthcare utilization. In US Veterans (USV) with opioid use disorder (OUD), there is sparse information about healthcare utilization, harm reduction prescription, and outcomes associated with IDU, including severe injection-related infections (SIRI). We assessed psychosocial factors, clinical outcomes, and harm reduction receipt in a cohort of USV with OUD, specifically focusing on persons who inject drugs (PWID).

METHODS

A retrospective cohort study was performed of USV aged ≥ 18 years with a diagnosis of OUD who presented to the Northport Veterans Affairs Medical Center (Long Island, NY) between 2012 and 2022. Demographics, psychosocial factors, history of human immunodeficiency virus (HIV), hepatitis C virus (HCV) infection, and healthcare utilization were compared by IDU status. Prescription of medications for opioid use disorder, naloxone and pre-exposure prophylaxis (PrEP) for HIV were also compared by IDU status. SIRI episodes and associated sequelae were characterized in USV with IDU.

RESULTS

A total of 502 USV with OUD were included and 216 (43%) were PWID. Mean age was 52.6 years. PWID were more likely to use multiple stimulants (14.4% PWID vs. 7.3% non-PWID, p < 0.011), be hospitalized with an infection (26.4% PWID vs. 12.2% non-PWID, p < 0.001) and had more frequent inpatient admissions (n = 5.5 PWID vs. n = 3.51 non-PWID, p = 0.003). Among PWID, 134 (62%) had a history of HCV infection, 9 (4.2%) had HIV, and 35 (16.2%) had at least one SIRI episode. PWID had a higher frequency of current (51.9% PWID vs. 38.5% non-PWID, p = 0.003) or previous MOUD use (45.8% PWID vs. 31.1% non-PWID, p < 0.001). Overall PrEP receipt in our cohort (0.46% PWID vs. 1.4% non-PWID, p = 0.4) was low.

CONCLUSIONS

USV with OUD and a history of IDU had a high prevalence of concurrent stimulant use, HCV, SIRI episodes, and were more likely to be hospitalized than USV with OUD and no history of IDU. Harm reduction strategies such as MOUD or PrEP, can help decrease the risk of infectious diseases, yet PrEP was underutilized in our population regardless of IDU status. USV with OUD would benefit from improved integration of OUD treatment, infectious diseases clinical care and harm reduction interventions.

Injecting drug use is a risk factor for methicillin resistance in patients with Staphylococcus aureus bloodstream infections

We investigated whether injecting drug use was a risk factor for methicillin resistance among inpatients with Staphylococcus aureus bloodstream infections (SABSIs) at an Australian health service. In 273 inpatients, 46 (16.9%) of SABSIs were methicillin-resistant S. aureus (MRSA). MRSA was more frequent in those who had injected drugs in the past 6 months (20.6%) compared with other inpatients (15.7%). Injecting drug use was associated with a 4.82-fold (95% confidence interval = 1.54-16.29) increased odds of MRSA after accounting for confounders.

How I manage severe bacterial infections in people who inject drugs

BACKGROUND

Injecting drug use is a risk factor for severe bacterial infection, but there is limited high-quality evidence to guide clinicians providing care to people who inject drugs. Management can be complicated by mistrust, stigma, and competing patient priorities.

OBJECTIVES

To review the management of severe infections in people who inject drugs, using an illustrative clinical scenario of complicated Staphylococcus aureus bloodstream infection.

SOURCES

The discussion is based on recent literature searches of relevant topics. Very few randomized clinical trials have focussed specifically on the management of severe bacterial infections among people who inject drugs. Most recommendations are, therefore, based on observational studies, extrapolation from other patient groups, and the experience and opinions of the authors.

CONTENT

We discuss evidence and options regarding the following management issues for severe bacterial infections among people who inject drugs: initial management of sepsis; indications for surgical management; assessment and management of substance dependence; approaches to antibiotic administration following clinical stability; opportunistic health promotion; and secondary prevention of bacterial infections. Throughout, we highlight the importance of harm reduction and strategies to optimize patient engagement in care through a patient-centred approach.

IMPLICATIONS

We advocate for a multi-disciplinary trauma-informed approach to the management of severe bacterial infection among people who inject drugs. We emphasize the need for pragmatic trials to inform management guidelines, including those that are co-designed with the community. In particular, research is needed to establish the comparative effectiveness, safety, and cost-effectiveness of inpatient intravenous antibiotics vs. early oral antibiotic switch, outpatient parenteral therapy, and long-acting lipoglycopeptide antibiotics in this scenario.

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.

Prevalence and incidence of emergency department presentations and hospital separations with injecting-related infections in a longitudinal cohort of people who inject drugs

People who inject drugs are at risk of acute bacterial and fungal injecting-related infections. There is evidence that incidence of hospitalizations for injecting-related infections are increasing in several countries, but little is known at an individual level. We aimed to examine injecting-related infections in a linked longitudinal cohort of people who inject drugs in Melbourne, Australia. A retrospective descriptive analysis was conducted to estimate the prevalence and incidence of injecting-related infections using administrative emergency department and hospital separation datasets linked to the SuperMIX cohort, from 2008 to 2018. Over the study period, 33% (95%CI: 31-36%) of participants presented to emergency department with any injecting-related infections and 27% (95%CI: 25-30%) were admitted to hospital. Of 1,044 emergency department presentations and 740 hospital separations, skin and soft tissue infections were most common, 88% and 76%, respectively. From 2008 to 2018, there was a substantial increase in emergency department presentations and hospital separations with any injecting-related infections, 48 to 135 per 1,000 person-years, and 18 to 102 per 1,000 person-years, respectively. The results emphasize that injecting-related infections are increasing, and that new models of care are needed to help prevent and facilitate early detection of superficial infection to avoid potentially life-threatening severe infections.

Opioid Injection-Associated Bacterial Infections in England, 2002-2021: A Time Series Analysis of Seasonal Variation and the Impact of Coronavirus Disease 2019

BACKGROUND

Bacterial infections cause substantial pain and disability among people who inject drugs. We described time trends in hospital admissions for injecting-related infections in England.

METHODS

We analyzed hospital admissions in England between January 2002 and December 2021. We included patients with infections commonly caused by drug injection, including cutaneous abscesses, cellulitis, endocarditis, or osteomyelitis, and a diagnosis of opioid use disorder. We used Poisson regression to estimate seasonal variation and changes associated with coronavirus disease 2019 (COVID-19) response.

RESULTS

There were 92 303 hospital admissions for injection-associated infections between 2002 and 2021. Eighty-seven percent were skin, soft-tissue, or vascular infections; 72% of patients were male; and the median age increased from 31 years in 2002 to 42 years in 2021. The rate of admissions reduced from 13.97 per day (95% confidence interval [CI], 13.59-14.36) in 2003 to 8.94 (95% CI, 8.64-9.25) in 2011, then increased to 18.91 (95% CI, 18.46-19.36) in 2019. At the introduction of COVID-19 response in March 2020, the rate of injection-associated infections reduced by 35.3% (95% CI, 32.1-38.4). Injection-associated infections were also seasonal; the rate was 1.21 (95% CI, 1.18-1.24) times higher in July than in February.

CONCLUSIONS

This incidence of opioid injection-associated infections varies within years and reduced following COVID-19 response measures. This suggests that social and structural factors such as housing and the degree of social mixing may contribute to the risk of infection, supporting investment in improved social conditions for this population as a means to reduce the burden of injecting-related infections.

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.