Ambulatory Intensive Care for Medically Complex Patients at a Health Care Clinic for Individuals Experiencing Homelessness: The SUMMIT Randomized Clinical Trial

IMPORTANCE: Intensive primary care interventions have been promoted to reduce hospitalization rates and improve health outcomes for medically complex patients, but evidence of their efficacy is limited. OBJECTIVE: To assess the efficacy of a multidisciplinary ambulatory intensive care unit (A-ICU) intervention on health care utilization and patient-reported outcomes. DESIGN, SETTING, AND PARTICIPANTS: The Streamlined Unified Meaningfully Managed Interdisciplinary Team (SUMMIT) randomized clinical trial used a wait-list control design and was conducted at a health care clinic for patients experiencing homelessness in Portland, Oregon. The first patient was enrolled in August 2016, and the last patient was enrolled in November 2019. Included patients had 1 or more hospitalizations in the prior 6 months and 2 or more chronic medical conditions, substance use disorder, or mental illness. Data analysis was performed between March and May 2021. INTERVENTION: The A-ICU included a team manager, a pharmacist, a nurse, care coordinators, social workers, and physicians. Activities included comprehensive 90-minute intake, transitional care coordination, and flexible appointments, with reduced panel size. Enhanced usual care (EUC), consisting of team-based primary care with access to community health workers and mental health, addiction treatment, and pharmacy services, served as the comparator. Participants who received EUC joined the A-ICU intervention after 6 months. MAIN OUTCOMES AND MEASURES: The main outcome was the difference in rates of hospitalization (primary outcome), emergency department (ED) visits, and primary care physician (PCP) visits per person over 6 months (vs the prior 6 months). Patient-reported outcomes included changes in patient activation, experience, health-related quality of life, and self-rated health at 6 months (vs baseline). We performed an intention-to-treat analysis using a linear mixed-effects model with a random intercept for each patient to examine the association between study group and outcomes. RESULTS: This study randomized 159 participants (mean [SD] age, 54.9 [9.8] years) to the A-ICU SUMMIT intervention (n = 80) or to EUC (n = 79). The majority of participants were men (102 [65.8%]) and most were White (121 [76.1%]). A total of 64 participants (41.0%) reported having unstable housing at baseline. Six-month hospitalizations decreased in both the A-ICU and EUC groups, with no difference between them (mean [SE], −0.6 [0.5] vs −0.9 [0.5]; difference, 0.3 [95% CI, −1.0 to 1.5]). Emergency department use did not differ between groups (mean [SE], −2.0 [1.0] vs 0.9 [1.0] visits per person; difference, −1.1 [95% CI, −3.7 to 1.6]). Primary care physician visits increased in the A-ICU group (mean [SE], 4.2 [1.6] vs −2.0 [1.6] per person; difference, 6.1 [95% CI, 1.8 to 10.4]). Patients in the A-ICU group reported improved social functioning (mean [SE], 4.7 [2.0] vs −1.1 [2.0]; difference, 5.8 [95% CI, 0.3 to 11.2]) and self-rated health (mean [SE], 0.7 [0.3] vs −0.2 [0.3]; difference, 1.0 [95% CI, 0.1 to 1.8]) compared with patients in the EUC group. No differences in patient activation or experience were observed. CONCLUSIONS AND RELEVANCE: The A-ICU intervention did not change hospital or ED utilization at 6 months but increased PCP visits and improved patient well-being. Longer-term studies are needed to evaluate whether these observed improvements lead to eventual changes in acute care utilization. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT03224858