From sea to shining IV: the current state of OPAT in the United States

Abstract

First described in the United States, outpatient parenteral antibiotic therapy (OPAT) has become an indispensable part of treating serious infections. The proportion of infectious disease (ID) physicians utilizing a formal OPAT program has increased in recent years, but remains a minority. In addition, many ID physicians have indicated that OPAT programs have inadequate financial and administrative support. Given the medical complexity of patients receiving OPAT, as well as the challenges of communicating with OPAT providers across health care facilities and systems, OPAT programs ideally should involve a multidisciplinary team. The majority of patients in the United States receive OPAT either at home with assistance from home infusion companies and visiting nurses or at a skilled nursing facility (SNF), though the latter has been associated with lower rates of patient satisfaction. Current and future opportunities and challenges for OPAT programs include providing OPAT services for people who inject drugs (PWID) and incorporating the increasing use of oral antibiotics for infections historically treated with parenteral therapy. In this review, we will discuss the current practice patterns and patient experiences with OPAT in the United States, as well as identify future challenges and opportunities for OPAT programs.

Introduction

Outpatient parenteral antimicrobial therapy (OPAT) was first described in the United States in 1974 for the treatment of pulmonary infections in children with cystic fibrosis. ¹ Since that time, advances in vascular access technology, infusion devices, antibiotic options, and the availability of structured support services have led to a significant expansion of OPAT. ² Bone and joint infections, endocarditis, bacteremia, and complicated skin/soft tissue infections are all now common indications for OPAT in the United States.^3,4 The Infectious Disease Society of America (IDSA) most recently released guidelines for OPAT programs in 2018, which highlight the ability of OPAT programs to reduce hospitalization duration and health care costs. ⁵ However, OPAT programs still face headwinds, often related to the fractured landscape of US health care.

Overview of the US Health Care System

In total, 330 million people living in the United States ⁶ are served by 417 different health systems, and over 6000 hospitals. ⁷ The United States has the unfortunate distinction of being the only wealthy industrialized nation without universal health coverage, with over 37 million uninsured and 41 million more with inadequate access to care. Affordability of health coverage is a common barrier for the uninsured population.^8,9 The United States has a mix of health insurance models, with some individuals receiving insurance through public funding (i.e. Medicare and Medicaid) and others receiving insurance through employers or purchased individually. In total, the United States has over 900 health insurance companies ¹⁰ with the majority covering home infusion services. However, a significant exception is Medicare, which is the government-administered, primary health insurance payor for adults over 65 years of age. Patients with Medicare may have to incur significant out-of-pocket costs for home infusion services. ¹¹

Current OPAT practice patterns and challenges in the United States

In the United States, OPAT programs are usually run by infectious diseases (ID) clinicians employed by academic medical centers or private practices. In a 2018 survey of 507 ID physicians in various clinical settings in the United States, 36% of respondents reported using a dedicated OPAT program or service to monitor patients on OPAT. ¹² This was increased from 26% in a 2012 survey of the same network of ID physicians by Lane et al., ¹³ though still clearly a minority. The presence of a formalized OPAT program is a strong recommendation made by the IDSA ⁵ and has been identified as a core quality indicator for OPAT. ¹⁴ The rates of reported adverse drug events and vascular access complications during OPAT vary across studies. ⁵ However, they are common enough to warrant regular lab monitoring, care coordination, and symptom management as important risk mitigation strategies. OPAT programs in the United States should ideally include physicians, advance practice providers, registered nurses, pharmacists, and medical coordinators, with other practitioners involved as needed to provide comprehensive care.^15,16

In the aforementioned 2018 survey study of ID physicians in the United States, only 37% reported that ID consultation was mandated prior to discharging patients on OPAT. ¹² This is notable as ID consultation during OPAT has been associated with improved outcomes ⁴ and is endorsed by the IDSA. ⁵ Most respondents did not feel that OPAT services were well-supported financially, and that administrative support was not adequate for the care of OPAT patients. ¹² Perceived barriers to safe OPAT care included laboratory results not returning in a timely fashion, lack of leadership support for OPAT, and difficulty with communication with providers at other facilities providing OPAT care. ¹² Of note, there are no current national standardized OPAT databases or repositories for benchmarking in the United States ⁵ despite the identification of outcome monitoring as a ‘core quality indicator’ for individual OPAT programs.^2,14

The patient experience in the United States

Patients receiving OPAT at home with assistance from home infusion companies and home health agencies is the most common OPAT delivery method in the United States, followed by patients receiving OPAT at post-acute care facilities [i.e. skilled nursing facilities (SNF), rehabilitation centers]. Patients may also receive OPAT care at an infusion center, either affiliated with a hospital system or owned by a physician group, or at their dialysis center. ¹²

Patients who receive OPAT at home in the United States are generally assigned an infusion company and a nurse from a visiting nurses association. ¹² Infusion companies are usually responsible for teaching patients and caregivers how to administer antimicrobials at home. This instruction generally occurs during the transition from the acute care facility to home. In a semi-structured interview of patients discharged home with OPAT, patients noted significant potential barriers to learning about OPAT during this time period. This included rushed instruction and confusing or inaccurate instruction manuals. ¹⁷ Infusion companies are also responsible for delivering medications and infusion supplies to patients during their treatment course. Visiting nurses will generally visit patients once weekly to change the dressing on their venous access device and draw labs. Thus, patients and caregivers are generally responsible for the daily administration of antibiotics. Despite these challenges and complexities, the safety of patients and caregivers self-administrating antimicrobials has been demonstrated by multiple observational studies^{18 –20} and is endorsed by the IDSA. ⁵

Patients in the United States who are insured by Medicare may also have daily costs for home services and medication supplies that are untenable. ¹¹ As a result, some Medicare patients may opt to receive OPAT care at infusion centers or at an SNF to avoid out-of-pocket costs. ²¹ However, patients who receive OPAT care at SNFs may have lower rates of satisfaction compared with patients receiving OPAT at home. ²¹ In addition, retrospective data from two health care systems in the United States suggest that patients who receive OPAT care at SNF may be more likely to be readmitted to an acute care facility.^22,23

Future challenges and opportunities for US OPAT programs

In the setting of increasing hospitalizations for infectious complications of opioid use disorder, ²⁴ there is a great need to evaluate the safety and efficacy of home OPAT for people who inject drugs (PWID). A 2018 systematic review found that OPAT completion rates, mortality, and catheter-related adverse events were similar among PWID and patients without injection drug practices. In addition, rates of misuse of venous catheters were low ²⁴ despite this being a reported barrier for US providers to enroll PWID in OPAT. ²⁵ OPAT programs in the United States have reported good outcomes for PWID who were enrolled in OPAT with concurrent addiction treatment.^26,27 However, many practices remain under-resourced to provide these services during OPAT.

The emergence of long-acting glycopeptides, including dalbavancin and oritavancin, also provides an attractive alternative to patients with serious infections who otherwise may not be ideal candidates for home OPAT therapy.^28,29 Though not approved for use outside of soft tissue infections by the US Food and Drug Administration (FDA), these antibiotics have been described in observational studies and a small randomized trial as effective treatment for serious infections such as infective endocarditis and osteomyelitis.^{29 –31} Though cost may be a barrier to use, the use of long-acting glycopeptides have been associated with shorter hospital length of stays, which is appealing for both patients and hospital administrators.^28,32

Another emerging opportunity and challenge for OPAT programs in the United States, similar to other parts of the world, is the increasing evidence from randomized controlled trials that oral therapy is equivalent to parenteral therapy for many infections historically treated with parenteral therapy (e.g. endocarditis and osteomyelitis). ³³ The use of oral therapy eliminates the complications and economic effects of long-term venous access devices. However, many oral regimens still require regular lab monitoring and close follow-up to ensure tolerability.^34,35 OPAT programs in the United States and elsewhere will still need to take an active role in helping to take care of these patients, and indeed some OPAT programs have been already rebranded as ‘COpAT’ (complex outpatient antimicrobial therapy). ³⁶

Conclusion

Over the last half-century, OPAT has grown to become an integral part of treating serious infections in the United States. However, despite the ability of OPAT to decrease hospital length of stay and health care costs, ⁵ a minority of ID clinicians in the United States use a formal multidisciplinary OPAT program. ¹² The relative lack of formal OPAT programs in the United States is detrimental to patient care, as these programs are essential for complex care coordination across health care systems. Ideally, the availability of dedicated OPAT teams in the United States will increase as clinicians and researchers continue to demonstrate their value to hospital administrators, insurers, and other governing bodies.