Background: The Acute Care for Elders (ACE) unit is an evidence-based system of acute hospital care starting from admission, designed to maintain or achieve independence and avoid preventable adverse events for older adults. However, little is known about how many ACE units exist and the variety of ways hospitals have implemented this evidence-based clinical model. Therefore, the aims of this study are to identify the prevalence of ACE Units in the United States and describe the variations in the implementation of this model of care.

Methods: We conducted a cross-sectional observational survey study involving all hospitals in the United States offering inpatient services. To identify potential ACE Units, we accessed the Definitive Healthcare Database to identify the names of eligible hospitals. To identify potential survey respondents from each hospital, we used: (1) purposeful sampling to identify clinicians known to the study team (2) snowball sampling methods based on our purposeful sampling efforts and (3) publicly available information to identify the contact details of up to three geriatricians, internists, or other geriatrics specialists (Figure 1). All identified ACE unit responders were sent an online survey that captured information on ACE Unit characteristics such as years of operation, number of beds, number of patients cared for, admission criteria and staffing. We also assessed the implementation of the five evidence-based components of ACE Units (patient-centered case assessments, medical care review, specialized prepared environment, early mobilization and physical therapy, early discharge planning). Survey results were summarized using descriptive statistics.

Results: There were 3692 eligible hospitals, and respondents from 2055 (56%) hospitals confirmed the presence of an ACE Unit or not (Figure 1). We identified 68 hospitals (3.3%) with an existing or previous ACE unit. Of these 68 hospitals, 50 respondents completed our entire survey where we found that 43 ACE units were currently open and 7 had been closed. Reasons for closure of the ACE unit were lost buy-in from hospital administration (2, 29%), the ACE service was not reliably used (2, 29%), a loss of physical space (1, 14%), strategic changes in hospital priorities (1, 14%), and finally ACE care was expanded to the entire hospital (1, 14%). Of the 50 open ACE units that responded to our survey, there is variable implementation of the five essential ACE components: 41 (95%) had patient-centered care assessments, 26 (69%) had a medical care review, 30 (70%) had a specialized prepared environment, 31 (72%) had early mobilization and physical rehabilitation, and 42 (98%) had early discharge planning. Other ACE Unit features are shown in Table 1.

Conclusions: There are 68 known ACE units in the United States (7 of which have closed). Open ACE units report variable implementation to the five essential components of an ACE unit. Further studies are needed to determine which implementation elements are critical to clinical and financial outcomes.

IMAGE 1: Figure 1: ACE Unit identification process and summary

IMAGE 2: Table 1: Characteristics of currently open ACE Units (n=43)