The role of emergency medicine in the hospital-at-home

Narrative Abstract

Hospital-at-home is an evidence-based model for delivering care in patient homes in lieu of a traditional hospital admission. Recent policy changes and technological advancement have spurred growth in hospital-at-home programs across the US. The role of emergency medicine in hospital-at-home programs has not been clearly defined. We argue that emergency medicine should contribute to the design, implementation, and leadership of these programs, as experts in management of acute illness and patient disposition. Further growth of hospital-at-home is likely to have important implications for the practice of emergency medicine, prompting adaptation and innovation. Finally, hospital-at-home offers a novel strategy to address ED boarding, although there is little evidence to suggest that these programs will meaningfully alleviate boarding in either the short or long-term.

Introduction

Hospital-at-Home (HaH) was introduced as an alternative care model nearly three decades ago.¹ HaH programs seek to replicate inpatient medical admissions in the setting of a patient’s home, offering analogous in-person and virtual services. Prior evaluations of HaH have reported comparable safety and effectiveness to standard hospital care, as well as reduced cost, fewer iatrogenic events, and improved patient satisfaction.^2–6 HaH is also touted as a strategy to improve hospital capacity, despite little evidence that these programs alleviate ED boarding.^7–11 Given the expanding demand for acute care services by an aging U.S. population, however, HaH offers an alternative strategy to help patients recover from acute illness outside the hospital.

As HaH programs expand to more health systems, the role of the ED in the HaH model needs further clarification.¹² As experts in patient disposition, emergency clinicians may be uniquely capable of determining which patients are best suited to receive HaH services in lieu of traditional hospital admission or observation. Yet little is known about the extent to which these programs involve ED operations, engage ED clinicians and leadership, or even accept patients directly from the ED. In this article, we seek to better define the role of EDs in HaH programs and describe the potential impact of these programs for the specialty of emergency medicine.

Current Landscape

HaH originated from research efforts at academic medical centers.¹³ Systematic reviews indicate that, for selected patients, HaH yields similar outcomes to traditional hospital care with lower cost and higher patient satisfaction.¹⁴ Much of the data supporting HaH comes from outside the United States, however, and there are concerns that evaluations have not fully accounted for the selection of healthier patients into HaH admissions.^11,15,16 Nevertheless, a randomized control trial in the US demonstrated a nearly 40% reduction in cost compared to standard admission, in addition to fewer readmissions and greater physical activity.¹⁷

The growth of HaH in the United States progressed slowly, in part because payers did not offer reimbursement for these services.^18,19 The COVID-19 pandemic, however, spurred rapid regulatory changes.²⁰ The Acute Hospital Care at Home (AHCaH) waiver program from the Centers for Medicare and Medicaid Services (CMS), launched in November 2020, allowed hospitals to receive full reimbursement for HaH admissions for Medicare fee-for-service beneficiaries.²¹ This policy had two goals: to mitigate the hospital capacity crisis exacerbated by the pandemic and to protect the safety of hospitalized patients with non-COVID illnesses.²¹ The waiver required hospitals to demonstrate sufficient infrastructure to deliver hospital-equivalent services at home. The concurrent growth of telemedicine also allowed hospitals to incorporate more technology in their programs.^11,20,21

Thus far, 337 hospitals across 136 health systems in 38 states have received the CMS waiver (Figure 1).¹² CMS reported over 13,000 admissions to HaH through January 2024, with the most common conditions including respiratory infection, sepsis, and heart failure.²² There have been few evaluations of patient outcomes for hospitals participating in the waiver program.^23,24 CMS has reported lower mortality rates for AHCaH admissions compared to traditional admissions, although this analysis does not adjust for differences in illness severity.²² One independent analysis reported that the 30-day mortality rate was less than 4 percent but did not include a comparison group.²⁵ Importantly, HaH has mostly been adopted by large, urban, non-profit hospitals, and HaH patients are more likely to be White and less likely to have low income.^12,22

Figure 1.

Number of hospitals that have received the Acute Hospital Care at Home (AHCaH) waiver from the Centers for Medicare and Medicaid Services, 2021–2024, by state.

Source: authors’ analysis of publicly available data from https://qualitynet.cms.gov/acute-hospital-care-at-home

Ongoing challenges for HaH to scale are likely related to the considerable resources, personnel, expertise, and motivation needed to create these programs over an extended runway, despite consistent findings of reduced costs once programs are active. Few institutions have been able to sustain meaningful volume for HaH programs.²⁶ Regardless, proponents of HaH, including health systems that have invested in HaH infrastructure, have drawn bipartisan political support. The US Senate introduced legislation to extend the AHCaH waiver program, which is set to expire in March 2025, for another five years. Commercial payers may wait for long-term congressional action before negotiating contracts with health systems.²⁷ Regardless of the fate of the current waiver program, innovation will likely continue as health systems grapple with the increasing demands of an aging population.^28–33

Emergency department admissions to hospital-at-home

The AHCaH waiver program prescribed specific requirements for HaH programs to receive reimbursement (Table 1). Because AHCaH and inpatient admissions are paid at equivalent rates, patients must qualify for inpatient services. To that end, a physical ED visit is required at the outset; patients cannot be admitted directly from home. Hospitals must provide specific inpatient services for the at-home patient (Table 1).²² Home visits can be performed by physicians, nurses, and mobile integrated health paramedics, with some virtual visits allowed.^21,22

Table 1.

Requirements for Acute Hospital Care at Home waiver program from the Centers for Medicare and Medicaid Services

Waiver requirements
Services, provided directly or through contracted vendor	Pharmacy
	Infusion
	Respiratory care including oxygen delivery
	Diagnostic testing, including laboratory and radiology services
	Monitoring of patient condition, with 2 sets of vital signs daily
	Transportation
	Food services, as needed by the patient
	Durable medical equipment
	Physical, occupational, and speech therapy
	Social work and care coordination services
Frequency of home and virtual engagement with clinicians	Physician or advanced practice provider (APP: NP/PA) - once daily Virtual encounter allowed after initial in-person history and physical exam performed by an admitting MD/APP
	Nurse or mobile integrated health paramedic – twice daily Must be in-person visits
	Nurse – once daily May be in-person or virtual
Performance metrics	Volume of patients admitted to the program
	Escalation rate Transfer back to the traditional hospital setting during the acute episode
	Unanticipated (non-hospice) mortality during acute admission
Additional requirements	Establish a local safety committee review to review the metrics listed above
	Ensure that only patients requiring an acute level of care are treated via HaH

Source: authors’ summary of public information from https://qualitynet.cms.gov/acute-hospital-care-at-home

HaH programs have primarily admitted common, low-acuity medical conditions that require hospital-level care without anticipated procedural or critical care escalation. Examples include acute decompensated heart failure, cellulitis, respiratory infection, and urinary tract infections.³⁴ In general, the diagnosis of these conditions, including imaging and laboratory testing, as well as initiation of treatment, occur in the ED prior to admission.

There are two routes for patients to enter HaH programs (Figure 2): ward transfer (early discharge) and ED transfer (admission avoidance). In the first, patients are admitted to standard medical wards but transferred to HaH prior to their expected hospital discharge. The second route seeks to divert admissions altogether.^35,36 Currently, the balance of ward versus ED transfer patients within active HaH programs is not known. However, there are multiple reasons to delineate these two routes, given their different implications for patients, hospitals, and emergency clinicians (Figure 2). Ward transfer patients generally benefit from more certain diagnoses and longer periods of observation prior to HaH entry. From the patient perspectives, ward transfers resemble hospital discharge but with enhanced services upon arrival home. By contrast, the ED transfer population provides the greatest reduction of time spent in the hospital, but may introduce greater clinical risk and logistical complexity.³⁷

Figure 2.

Two routes of admission to hospital-at-home: emergency department (ED) transfer and ward transfer

ED transfer patients may partially overlap with those who currently receive care in ED observation units.^28,38 Although objective clinical criteria are generally used to distinguish patients that merit admission versus observation, ED clinician discretion also influences this decision. Greater reimbursement for HaH (at the inpatient rate) may have an unintended consequence of diverting patients that would otherwise receive care in observation units. Furthermore, HaH programs may paradoxically increase the overall complexity of patients sent to observation units and medical wards by diverting patients with less acute illness and more supported home environments.

The role of emergency clinicians

The role of emergency clinicians in HaH programs remains undefined, and there is a major evidence gap on the optimal role of emergency medicine within this model (Table 2). We propose two paradigms for ED involvement in HaH (Figure 3). In the first paradigm, patients are triaged to hospital-at-home services after an ED clinician has decided to admit them. In this approach, the decision to offer HaH is fully deferred to the admitting team and the workflow of emergency clinicians is not interrupted, leaving inpatient and HaH teams to review admission guidelines, obtain patient and family consent, and coordinate logistics.^9,17,23 This model may be appealing to ED clinicians concerned about accepting accept any additional coordination, documentation, or communication tasks during their already busy shifts. However, it is unclear whether this approach is optimal for patients and the effectiveness of these programs in effectively diverting admissions to home.

Table 2.

Selected knowledge gaps for the intersection of emergency medicine and hospital-at-home

Knowledge gap	Potential research and operations questions
Balance of ED transfer and ward transfer patients	How often are patients admitted to HaH from the ED versus inpatient units? What are clinical and/or social differences in ED transfer versus ward transfer patients? How are outcomes for HaH different for ED transfer and ward transfer patients?
Optimal ED engagement in hospital-at-home admission	What is the optimal role for ED clinicians be in the admission of patients into HaH programs? How might ED engagement in triage to HaH improve outcomes and patient experience? What additional administrative and clinical responsibilities for HaH may arise for ED clinicians?
Impact on ED patient disposition	How does the availability of HaH change the disposition of patients that would have been admitted under observation rather than inpatient status? How does the availability of HaH change the disposition of patients that would otherwise have been discharged? How do HaH programs affect ED length-of-stay and overall patient throughput?
Impact on health equity	How should HaH programs address social needs to avoid exacerbating access or outcomes disparities? How do explicit and implicit bias impact decisions to admit patients to HaH services? How can HaH programs mitigate inequitable burdens on caregivers with fewer resources?
Benefit of hospital-at-home model versus virtual observation	Are virtual observation models, with less intensive home services, equally effective at caring for patients that would have been admitted to HaH programs? Will reimbursement become available for virtual observation services, in addition to full HaH services?
Impact on ED boarding	How can HaH programs, at scale, be effective interventions to alleviate hospital and ED capacity strain in both the short-term and long-term?

Figure 3.

Potential adaptation of traditional emergency medicine disposition paradigm to incorporate hospital-at-home and other admission alternatives

A second paradigm would engage ED clinicians in the decision-making process from the moment that patients are triaged and evaluated. As experts in disposition, ED clinicians can effectively weigh HaH admission against standard options, including critical care, admission, observation, and routine discharge. Disposition decisions are often made early in the patient’s evaluation, with anticipatory guidance communicated to patients and their families. Early identification of logistical barriers and facilitators, such as the availability of home caregivers, may streamline the HaH admission process. Regardless of whether ED clinicians determine that a patient may be a candidate for this service, better integration of HaH admissions with ED operations can mitigate delays prior to transfer home.

A common challenge for HaH programs is achieving adequate volume to justify the investment of resources and personnel for the program.¹¹ Guidelines with objective criteria are essential to ensure patient safety. Yet some patients that meet objective criteria for HaH admission may not be deemed suitable by ED clinicians based on their subjective evaluation, which remains a key element in emergency medicine decision-making.³⁹ The converse may also be true, and guidelines will inevitably require collaborative adjustment and refinement over time.

Importantly, early ED engagement should not come at the cost of placing overwhelming burdens on ED clinicians. HaH programs should be designed such that a collaborative team can screen, admit, and manage patients in these programs, including admission coordinators, social work, pharmacists, and dedicated HaH hospitalists. The admission workflow to HaH should also be integrated into the electronic health record, in the same way that ED clinicians use automated admission or discharge order sets.

Implications for the specialty of emergency medicine

It remains to be seen whether HaH will see widespread adoption across the US. If it does, this innovative disposition option may not only change the daily practice of emergency medicine but also lead to long-term changes to the specialty.

Emergency medicine has traditionally focused on optimizing the care delivered within the ED rather than longitudinal services or outcomes. Accordingly, other disciplines have assumed leadership of HaH programs, most often internal medicine.⁴⁰ However, involvement of the ED has been cited as a necessary step in the successful development and operation of HaH programs.³⁷ ED engagement is important to ensure that HaH optimizes volume and patients receive the appropriate disposition. Even if the clinical purview of EM clinicians does not extend to the management of patients at home, we argue that ED clinicians should help lead HaH programs and contribute to their design, implementation, and improvement.

HaH may eventually provide additional career or even sub-specialty options for ED clinicians. Physicians with training in emergency medicine may seek new skills in managing patients virtually or in the home setting, allowing them to manage patients beyond the threshold of the hospital. Just as ED clinicians have been incorporated into observation units, HaH programs may ask ED clinicians to place orders or respond to clinical changes. Ultimately, management of patients in the home remains outside the current scope of emergency medicine, and individual health systems should deploy the optimal clinical resources to manage patients effectively.

Another implication is equity. As HaH evolves, patients may increasingly be divided into two categories: those who remain in traditional hospitals due to social needs and those that can be admitted to HaH.⁴¹ Admission to HaH requires a structured assessment of social needs. Furthermore, the role of clinician discretion in determining which patients are appropriate candidates—creates new opportunities for implicit bias. The intersection of equity, bias, and patient choice is complex. While HaH programs have generally demonstrated high levels of patient satisfaction, some historically marginalized populations may decline this option due to concerns that appropriate care will be withheld. Furthermore, it is also possible that HaH programs may place more inequitable burdens on caregivers with fewer resources and ability to stay at home.⁴² A fair and informed process that accounts for family and cultural factors is needed to ensure robust consent and mitigate clinician bias.⁴³

Finally, there is concern that the availability of HaH may inadvertently increase ‘unnecessary’ admissions. An essential part of emergency medicine practice is gaining tolerance for relatively higher-risk discharges, particularly for patients that can be managed in the outpatient setting but have important issues that require close follow-up. The availability of HaH may induce clinicians, regardless of their risk tolerance, to “admit” patients that meet basic HaH admission criteria on paper but would not otherwise be hospitalized, as a way of mitigating anticipated risks upon discharge. Similarly, the availability of HaH might shift patients from inpatient observation status to HaH admission. While arguably better for patients, increased costs and effort for avoidable HaH admissions may undermine the objectives of the program.²⁸

Impact of hospital at home on emergency department boarding

The potential for improved capacity in hospitals and EDs has driven much of the enthusiasm for the adoption of the AHCaH waiver. CMS continues to cite increasing capacity within hospitals as a reason to further extend the waiver.²⁷ For academic health systems, which have been particularly affected by ED boarding crises, opening hospital beds has been stated as the primary goal for implementing HaH programs.^22,44 In the lay media, HaH is cited as an innovative strategy to deliver care while relieving overwhelmed EDs.⁸

Both types of HaH admissions, ED transfer and ward transfer, have a putative impact on ED boarding, which is caused by structural factors driving high inpatient bed occupancy.⁴⁵ ED and ward transfer both seek to ‘open’ a hospital bed, theoretically improving throughput for additional patients awaiting admission. ED transfer patients would have greater impact on hospital length-of-stay reduction, although importantly, many hospitals might not count these zero-length admissions without modifying length-of-stay metrics. Under the current Medicare reimbursement policy, HaH could allow hospitals to ‘win’ twice – reducing length-of-stay to increase revenue from additional in-hospital admissions while still earning revenue from patients admitted to HaH.

However, it is not yet clear that HaH can meaningfully alleviate hospital capacity strain or ED boarding. First, most active HaH programs have not achieved sufficient volume to meaningfully reduce length-of-stay across an entire hospital or health system. Second, while programs have expanded rapidly under the waiver, these programs are still limited to a relatively small number of hospitals.¹² Reimbursement is just one of many barriers for these programs to reach the scale necessary to open sufficient hospital beds.

Even if HaH programs were to scale, the same economic forces that generate ED boarding may undermine their positive impact. Hospitals that implement HaH would be motivated to fill the newly open beds with new patients, particularly high revenue surgical patients, or potentially eliminate unnecessary beds to save costs. Occupancy may decline temporarily but then increase again, a phenomenon demonstrated when hospitals build new physical beds.^45,46 While well-resourced hospitals would gain in this scenario, hospitals that do not have the resources to implement HaH would face a competitive disadvantage, potentially leading to further closures that decrease system-wide capacity. Remaining hospitals may start to resemble concentrated critical care units and operating rooms, with routine medical care shifted to the home. These long-term scenarios may seem far-fetched, but it is essential to monitor real-world data to examine the impact of these programs.

Emergency medicine adaptation of the hospital-at-home model

Further innovation and experimentation may be needed outside of the regulatory structure imposed by the CMS waiver. HaH programs will continue to incorporate new types of medical technology, including remote monitoring devices and telemedicine. More flexible programs, which have been called “virtual observation units,” may be needed with different designs tailored to specific disease conditions or populations.^29,32,38 These less intensive home management programs may not have the same expectation for fully duplicating hospital services, with less strict requirements for home nursing or physician visits. So far, these novel programs have generally not received reimbursement to date, limiting their growth. Yet emergency medicine may be poised to have greater clinical and administrative leadership of these observation equivalent programs, in which the care delivered may fall more within scope of emergency and observation medicine than hospital medicine.

Conclusion

As a specialty, emergency medicine has innovated from its inception. Emergency clinicians can play an important role in leading efforts to expand HaH across the nation. The growth of HaH will create changes within our specialty—some of which will be welcome, while others may require ED engagement to prevent overburdening departments and clinicians. At this juncture, more is uncertain about the future of HaH, and its eventual impact on hospitals and EDs, than is known. This uncertainty, though, offers an opportunity for emergency medicine to help shape a vision for hospital transformation and acute care delivery in the coming decade.