Noninpatient Alternative Treatment Venues for Acute Care Needs

Importance Hospitalizations are costly and may lead to adverse events. Some health systems offer treatment in alternative venues of care for select patients. Objective To describe use and short-term outcomes of emergency department (ED) patients transitioned to noninpatient care settings (ambulatory treatment center [ATC], advanced care at home [ACAH], or emergency department observation unit [EDOU]) compared with inpatient care. Design, Setting, and Participants This retrospective cohort study of ED patients aged 19 years or older was conducted from January 1, 2024, to June 30, 2025, at multisite community ED and inpatient medical centers within an integrated delivery system (Kaiser Permanente Northern California). Included patients had active health plan membership; had an ED visit for heart failure, pneumonia, cellulitis, urinary tract infection, COVID-19, or anemia; and had their care transitioned to an ATC, ACAH program (Kaiser Permanente Advanced Care at Home), EDOU, or inpatient bed. Exposure Treatment venue. Main Outcomes and Measures The main outcomes were care escalation (inpatient admission) for patients treated in an ATC, ACAH program, or EDOU, as well as 7-day ED return visits, 30-day hospitalizations, and 30-day mortality following care completion across all venues. Unadjusted outcome rates are reported. Results This study included 26 618 ED encounters (median patient age, 77 years [IQR, 65-85 years]; 52.6% female). Among 22 755 unique patients, 87.4% had 1 encounter, 9.8% had 2 encounters, and 2.8% had more than 2 encounters. There were 728 (2.7%), 880 (3.3%), 5133 (19.3%), and 19 877 (74.7%) encounters in ATC, ACAH, EDOU, and hospital settings, respectively. One-quarter of patients (25.3%) received care in an ATC, ACAH program, or EDOU. Inpatient admission rates were lower for ATC and ACAH encounters than for EDOU encounters (4.3% [95% CI, 2.7%-5.8%], 5.3% [3.8%-6.8%], and 28.0% [26.8%-29.2%], respectively). Rates of 7-day ED visits were similar across venues (ATC: 10.4% [95% CI, 7.8%-12.9%]; ACAH: 5.3% [3.8%-6.8%]; EDOU: 9.2% [8.4%-10.0%]; and hospital: 8.5% [8.1%-8.9%]). In contrast, 30-day mortality and hospitalization rates were lower among ATC, ACAH, and EDOU encounters than in hospital encounters (30-day mortality: 2.1% [95% CI, 1.0%-3.2%], 1.7% [0.8%-2.6%], 2.8% [2.3%-3.2%], and 5.3% [5.0%-5.6%]; and 30-day hospitalization: 11.4% [95% CI, 8.8%-14.1%], 8.3% [6.3%-10.2%], 12.7% [11.7%-13.7%], and 15.3% [14.7%-15.8%], respectively). Conclusions and Relevance In this cohort study of patients treated in alternative venues of care, one-quarter received care in an ATC, ACAH program, or EDOU. These findings suggest that adoption of novel treatment spaces for appropriately selected patients may allow health systems to focus hospital resources on the patients with the most complex needs.