Cost-effectiveness of outpatient parenteral antibiotic therapy: a simulation modelling approach

[Translated article] Retrospective study of home antibiotic infusion therapy using elastomeric infusion pumps

OBJECTIVES

To describe the experience of home antibiotic infusion therapy using elastomeric infusion pumps, administered to patients admitted to the Home Hospitalisation Unit of a tertiary hospital for 3 years and to analyse clinical evolution and mortality.

METHOD

Retrospective observational study. The medical history of the patients included in the study was reviewed. Information was obtained on personal history, antimicrobial therapy received, and clinical evolution. Statistical analysis was performed using SPSS® 19 software.

RESULTS

81 patients were included, 61.7% men, with a mean age of 73.5±17.5 years. The most frequent comorbidities were diabetes mellitus (30.9%) and chronic kidney disease (28.4%). Patients received a mean of 11.9±8.5 days of antibiotic treatment in an elastomeric infusion pump. The main focus of infection was respiratory (27.2%), followed by bacteremia (16%) and skin and soft tissue infections (12.3%). Of the infections, 65.4% were monomicrobial, with Pseudomonas aeruginosa being the main microorganism involved (39.6%). The most commonly used antimicrobial was piperacillin/tazobactam (33.3%). The clinical course was good in 85.2% of the patients, but the mortality rate in the 30 days following the end of treatment was 24.7%. In the univariate analysis, a history of neoplasia in the last 5 years (p=.01) and having received fewer days of antibiotic therapy prior to the start of outpatient antimicrobial therapy in infusion pump (p=.04) were associated with worse clinical outcome. Age over 80 years was associated with better outcome (p=.03). The diagnosis of heart failure was associated with higher mortality (p=.026) and patients from surgical services, with lower mortality (p=.047). In the multivariate analysis, the presence of neoplasia was associated with unfavourable evolution (p=.012) and heart failure with higher mortality (p=.027).

CONCLUSIONS

Outpatient antimicrobial therapy in elastomeric infusion pumps is an alternative in patients requiring prolonged intravenous treatment, and age is not a conditioning factor for inclusion in these programs. However, the presence of certain comorbidities can negatively affect the clinical course and mortality of patients.

Retrospective study of home antibiotic infusion therapy in elastomeric infusion pumps

OBJECTIVES

To describe the experience of home antibiotic infusion therapy using elastomeric infusion pumps, administered to patients admitted to the Home Hospitalization Unit of a tertiary hospital for three years and to analyse clinical evolution and mortality.

METHOD

Retrospective observational study. The medical history of the patients included in the study was reviewed. Information was obtained on personal history, antimicrobial therapy received and clinical evolution. Statistical analysis was performed using SPSS® 19 software.

RESULTS

Eighty-one patients were included, 61.7% men, with a mean age of 73.5 ± 17.5 years. The most frequent comorbidities were diabetes mellitus (30.9%) and chronic kidney disease (28.4%). Patients received a mean of 11.9 ± 8.5 days of antibiotic treatment in an elastomeric infusion pump. The main focus of infection was respiratory (27.2%), followed by bacteremia (16%) and skin and soft tissue infections (12.3%). Of the infections, 65.4% were monomicrobial, with Pseudomonas aeruginosa being the main microorganism involved (39.6%). The most commonly used antimicrobial was piperacillin/tazobactam (33.3%). The clinical course was good in 85.2% of the patients, but the mortality rate in the 30 days following the end of treatment was 24.7%. In the univariate analysis, a history of neoplasia in the last 5 years (p = 0.01) and having received fewer days of antibiotic therapy prior to the start of outpatient antimicrobial therapy in infusion pump (p = 0.04) were associated with worse clinical outcome. Age over 80 years was associated with better outcome (p = 0.03). The diagnosis of heart failure was associated with higher mortality (p = 0.026) and patients from surgical services, with lower mortality (p = 0.047). In the multivariate analysis, the presence of neoplasia was associated with unfavorable evolution (p = 0.012) and heart failure with higher mortality (p = 0.027).

CONCLUSIONS

Outpatient antimicrobial therapy in elastomeric infusion pumps is an alternative in patients requiring prolonged intravenous treatment, and age is not a conditioning factor for inclusion in these programs. However, the presence of certain comorbidities can negatively affect the clinical course and mortality of patients.

A cost minimisation analysis comparing oral linezolid and intravenous daptomycin administered via an outpatient parenteral antibiotic therapy programme in patients requiring prolonged antibiotic courses

This study is an economic analysis seeking to examine cost savings that may be accrued from usage of oral linezolid in place of OPAT IV daptomycin in patients requiring prolonged courses of IV or highly bioavailable oral antibiotic therapy. In order to do so we conducted a literature review to establish the scenarios in which the agents could be considered equivalent. We then, using a decision-tree model, conducted a cost analysis to establish differences in cost between the approaches. Under the model base-case, the total cost of treatment with OPAT daptomycin was €3,496.84 and the total cost of treatment with oral linezolid was €772.01. Therefore the oral linezolid strategy would be projected to save the Irish health service €2,724.83 per patient. These results were robust to one-way deterministic sensitivity analyses and probabilistic sensitivity analysis. Our study suggests that significant savings could be safely accrued in the management of these patients.

Ampicillin Stability in a Portable Elastomeric Infusion Pump: A Step Forward in Outpatient Parenteral Antimicrobial Therapy

Outpatient parenteral antimicrobial therapy (OPAT) with continuous infusion pumps is postulated as a very promising solution to treat complicated infections, such as endocarditis or osteomyelitis, that require patients to stay in hospital during extended periods of time, thus reducing their quality of life and increasing the risk of complications. However, stability studies of drugs in elastomeric devices are scarce, which limits their use in OPAT. Therefore, we evaluated the stability of ampicillin in sodium chloride 0.9% at two different concentrations, 50 and 15 mg/mL, in an elastomeric infusion pump when stored in the refrigerator and subsequently in real-life conditions at two different temperatures, 25 and 32 °C, with and without the use of a cooling device. The 15 mg/mL ampicillin is stable for up to 72 h under refrigeration, allowing subsequent dosing at 25 °C for 24 h with and without a cooling device, but at 32 °C its concentration drops below 90% after 8 h. In contrast, 50 mg/mL ampicillin only remains stable for the first 24 h under refrigeration, and subsequent administration at room temperature is not possible, even with the use of a cooling system. Our data support that 15 mg/mL AMP is suitable for use in OPAT if the volume and rate of infusion are tailored to the dosage needs of antimicrobial treatments.

A single centre experience of prosthetic joint infection outcomes with outpatient parenteral antimicrobial therapy

Objectives

Prosthetic joint infection (PJI) is a serious complication following arthroplasties. This study assessed the clinical outcomes, readmission rates and financial impact of PJIs treated with outpatient parenteral antimicrobial therapy (OPAT).

Methods

The study used prospectively collected data from the OPAT patient database at a tertiary care Irish hospital for PJI cases managed between 2015 and 2020. Data was analyzed using IBM-SPSS.

Results

Forty-one patients with PJIs were managed via OPAT over five years, with median age of 71.6 years. Median duration of OPAT was 32 days. Hospital readmission occurred in 34% of cases. Reasons for readmission included progression of infection in 64.3%, unplanned reoperation in 21.4% and planned admission for joint revision in 14.3%. Type 2 Diabetes Mellitus (T2DM) was found to have a statistically significant association with unplanned readmission (OR 8.5, CI 95% 1.1-67.6; p < 0.01). OPAT saved a mean of 27.49 hospital-bed days per patient. 1,127 bed days were saved in total, estimating a total savings of 963,585 euros and median savings of 26,505 euros.

Conclusions

The readmission rate observed was comparable to international data. Most readmissions were related to primary infections rather than due to OPAT-specific complications. Our main findings were that patients with PJIs can be safely managed via OPAT, and the finding of association between T2DM and increased risk of readmission.

Impact of an outpatient parenteral antimicrobial treatment (OPAT) as part of a paediatric-specific PROA program

INTRODUCTION

Outpatient parenteral antimicrobial treatment (OPAT) is an alternative to in-patient care in carefully selected patients. This study presents a self-administration OPAT program integrated within the pediatric antibiotic stewardship program (ASP) in a pediatric tertiary care center.

MATERIAL AND METHODS

Descriptive, retrospective and unicentric study. Data from all patients under 20 years of age who were prescribed treatment by a pediatric unit during 2019 and 2020 were included. Data regarding number of saved beds and estimating the opportunity cost of the OPAT program for the hospital were analyzed.

RESULTS

Fifty-seven patients received 106 episodes of treatment. Favorable clinical outcome occurred in 74.5% of the episodes. The main cause of premature interruption was unfavorable clinical outcome of the infection (37.1%). A total of 2.62 beds/day were saved, resulting in an economic benefit of 1,069,963 €.

CONCLUSION

A self-administration OPAT program integrated within the pediatric ASP has proven to be safe and effective and provides economic benefits.

Antibiotic stability in portable elastomeric infusion devices: A systematic review

DISCLAIMER

In an effort to expedite the publication of articles related to the COVID-19 pandemic, AJHP is posting these manuscripts online as soon as possible after acceptance. Accepted manuscripts have been peer-reviewed and copyedited, but are posted online before technical formatting and author proofing. These manuscripts are not the final version of record and will be replaced with the final article (formatted per AJHP style and proofed by the authors) at a later time.

PURPOSE

Although outpatient parenteral antibiotic therapy (OPAT) can be a good approach to treatment of infections, a lack of data regarding antibiotic stability in portable elastomeric infusion devices restricts its safe, appropriate, and effective use. The objective of this work was to complete a systematic peer-reviewed analysis of published articles about antibiotic stability in elastomeric infusion devices that provide evidence supporting their use in OPAT.

SUMMARY

A systematic review following PRISMA guidelines was conducted in January 2021 to identify published articles about antibiotic stability in portable elastomeric infusion devices. The databases used were PubMed, Embase, Web of Science, and a Cochrane database. A total of 1,615 original studies and conference communications were found. After title, abstract, and full-text review, 33 articles met the inclusion criteria. The data obtained included information about the stability of 30 different antibiotics. To our knowledge, this is the first review to summarize the available published data on the stability of antibiotics in portable elastomeric infusion devices. The results highlight the poor stability of some antibiotics in solution and the variability of the laboratory conditions in the included studies.

CONCLUSION

This systematic review can serve as a useful resource for healthcare professionals involved in providing OPAT using portable elastomeric infusion devices. However, further stability studies should be performed, especially high-quality studies simulating real-life time and temperature conditions.

Intravenous catheter-related adverse events exceed drug-related adverse events in outpatient parenteral antimicrobial therapy

BACKGROUND

Drug-related adverse events (AEs) are reported to be common amongst patients receiving outpatient parenteral antimicrobial therapy (OPAT). However, comparative data regarding intravenous (iv) catheter-related AEs are lacking.

OBJECTIVES

To compare drug- and iv catheter-related AEs from a large UK OPAT centre.

PATIENTS AND METHODS

We reviewed 544 OPAT episodes [median (IQR) age: 57 (39-71) years, 60% male, 13% with diabetes] with a median (IQR) duration of 7 (2-18) days. Clinically significant drug- and iv catheter-related AEs were calculated as a percentage of OPAT episodes with an AE and also as AEs per 1000 iv drug/catheter days.

RESULTS

Drug-related AEs complicated 13 (2.4%) OPAT episodes at 1.7 (95% CI 0.9-2.9) per 1000 drug days. Catheter-related AEs occurred more frequently, complicating 32 (5.9%) episodes at 5.7 (95% CI 4.2-7.9) per 1000 iv catheter days (χ2 test for difference in AE rate: P < 0.001). Non-radiologically guided midline catheters were associated with the most frequent AEs (n = 23) at 15.6 (95% CI 10.3-23.4) per 1000 iv catheter days compared with other types of iv catheters (HR 8.4, 95% CI 2.4-51.9, P < 0.004), and self-administration was associated with a higher rate of catheter-related AEs at 12.0 (95% CI 6.0-23.9) per 1000 iv catheter days (HR 4.15, 95% CI 1.7-9.1, P = 0.007).

CONCLUSIONS

Clinically significant iv catheter-related AEs occurred more frequently than drug-related AEs, especially when using non-radiologically guided midline catheters. Regular review of the need for iv therapy and switching to oral antimicrobials when appropriate is likely to minimize OPAT-related AEs.

Organisational and financial consequences of the early discharge of patients treated for acute bacterial skin and skin structure infection and osteomyelitis in infectious disease departments in Greece, Italy and Spain: a scenario analysis

OBJECTIVE

The aim of the analysis is to assess the organisational and economic consequences of adopting an early discharge strategy for the treatment of acute bacterial skin and skin structure infection (ABSSSI) and osteomyelitis within infectious disease departments.

SETTING

Infectious disease departments in Greece, Italy and Spain.

PARTICIPANTS

No patients were involved in the analysis performed.

INTERVENTIONS

An analytic framework was developed to consider two alternative scenarios: standard hospitalisation care or an early discharge strategy for patients hospitalised due to ABSSSI and osteomyelitis, from the perspective of the National Health Services of Greece, Italy and Spain. The variables considered were: the number of annual hospitalisations eligible for early discharge, the antibiotic treatments considered (ie, oral antibiotics and intravenous long-acting antibiotics), diagnosis-related group (DRG) reimbursements, number of days of hospitalisation, incidence and costs of hospital-acquired infections, additional follow-up visits and intravenous administrations. Data were based on published literature and expert opinions.

PRIMARY AND SECONDARY OUTCOME MEASURES

Number of days of hospitalisation avoided and direct medical costs avoided.

RESULTS

The total number of days of hospitalisation avoided on a yearly basis would be between 2216 and 5595 in Greece (-8/-21 hospital beds), between 15 848 and 38 444 in Italy (-57/-135 hospital beds) and between 7529 and 23 520 in Spain (-27/-85 hospital beds). From an economic perspective, the impact of the early discharge scenario is a reduction between €45 036 and €149 552 in Greece, a reduction between €182 132 and €437 990 in Italy and a reduction between €292 284 and €884 035 in Spain.

CONCLUSIONS

The early discharge strategy presented would have a positive organisational impact on National Health Services, leading to potential savings in beds, and to a reduction of hospital-acquired infections and costs.

Cost-utility analysis of outpatient parenteral antimicrobial therapy (OPAT) in the Brazilian national health system

BACKGROUND

Outpatient parenteral antimicrobial therapy (OPAT) has been used for decades in different countries to reduce hospitalization rates, with favorable clinical and economic outcomes. This study assesses the cost-utility of OPAT compared to inpatient parenteral antimicrobial therapy (IPAT) from the perspective of a public university hospital and the Brazilian National Health System (Unified Health System -SUS).

METHODS

Prospective study with adult patients undergoing OPAT at an infusion center, compared to IPAT. Clinical outcomes and quality-adjusted life year (QALY) were assessed, as well as a micro-costing. Cost-utility analysis from the hospital and SUS perspectives were conducted by means of a decision tree, within a 30-day horizon time.

RESULTS

Forty cases of OPAT (1112 days) were included and monitored, with a favorable outcome in 97.50%. OPAT compared to IPAT generated overall savings of 31.86% from the hospital perspective and 26.53% from the SUS perspective. The intervention reduced costs, with an incremental cost-utility ratio of -44,395.68/QALY for the hospital and -48,466.70/QALY for the SUS, with better cost-utility for treatment times greater than 14 days. Sensitivity analysis confirmed the stability of the model.

CONCLUSION

Our economic assessment demonstrated that, in the Brazilian context, OPAT is a cost-saving strategy both for hospitals and for the SUS.

A retrospective analysis of adverse events among patients receiving daptomycin versus vancomycin during outpatient parenteral antimicrobial therapy

OBJECTIVE

Outpatient parenteral antimicrobial therapy (OPAT) is a safe and effective alternative to prolonged inpatient stays for patients requiring long-term intravenous antimicrobials, but antimicrobial-associated adverse events remain a significant challenge. Thus, we sought to measure the association between choice of antimicrobial agent (vancomycin vs daptomycin) and incidence of adverse drug events (ADEs).

METHODS

Patients receiving OPAT treatment with vancomycin or daptomycin for skin and soft-tissue infections, bone and joint infections, endocarditis, and bacteremia or endovascular infections during the period from July 1, 2013, through September 30, 2016, were included. Demographic and clinical data were abstracted from the medical record. Logistic regression was used to compare ADEs requiring a change in or early discontinuation of therapy, hospital readmission, and emergency room visits between groups. Time from OPAT enrollment to ADE was compared using the log-rank test.

RESULTS

In total, 417 patients were included: 312 (74·8%) received vancomycin and 105 (25·2%) received daptomycin. After adjusting for age, Charlson comorbidity index, location of OPAT treatment, receipt of combination therapy with either β-lactam or fluoroquinolone, renal function, and availability of safety labs, patients receiving vancomycin had significantly higher incidence of ADEs (adjusted odds ratio [aOR], 3·71; 95% CI, 1·64-8·40). ADEs occurred later in the treatment course for patients treated with daptomycin (P<·01). Rates of readmission and emergency room visits were similar.

CONCLUSIONS

In the OPAT setting, vancomycin use was associated with higher incidence of ADEs than daptomycin use. This finding is an important policy consideration for programs aiming to optimize outcomes and minimize cost. Careful selection of gram-positive agents for prolonged treatment is necessary to limit toxicity.