Impact of an acute geriatric outreach service to residential aged care facilities on hospital admissions

Abstract Introduction Residential aged care facility (RACF) residents frequently present to the emergency department (ED) and are often admitted to hospital. Some presentations and admissions may be avoidable. In 2013, Bankstown‐Lidcombe Hospital introduced a subacute geriatric outreach service (SGOS), which had little impact on reducing ED presentations. In 2015, Bankstown‐Lidcombe Hospital introduced an acute geriatric outreach service (AGOS), a geriatrician‐led team that assesses and treats acutely unwell patients in RACFs. We aim to determine whether the AGOS reduces the risk of hospital admission for RACF residents. Methods Hospital admissions data from 2010 to 2019 were used to conduct an interrupted time series (ITS) analysis. AGOS activity data were also summarized. Results The average number of admissions from RACF per month declined from 42.8 during the SGOS period to 27.1 during the AGOS period. The difference of 15.7 admissions from RACF per month was statistically significant (95% CI 12.1–19.2; P < .001). After the introduction of the AGOS, the risk of admission to our geriatric department from RACFs was reduced by 36.1% (incidence rate ratio =0.64; 95% CI: 0.58–0.71; P < .001) compared to the SGOS period, adjusting for seasonality. Discussion The AGOS probably reduced the risk of hospital admission for RACF residents.


| INTRODUC TI ON
Australians aged 65 and older are projected to rise from 15% in 2016 to 19% by 2030. 1 Over 170, 000 adults aged 65 and older live in residential aged care facilities. 2 People living in residential aged care facilities (RACFs) are often frail and have medically complex care needs. The average age of RACF residents is 84.5 years. Fifty percent of residents have dementia, 26% have a mental illness but no dementia, and 22% neither have dementia or a mental illness. Twenty-nine percent of male and 18% of female residents have had a stroke, head injury, or acquired brain injury. Fiftyfour percent of residents have a musculoskeletal disorder, 18% have heart disease, 10% have another neurological disorder, and 7% have cancer. 3 RACF residents are at greater risk of emergency department (ED) representations and hospital readmissions. 4 They present to EDs at rates of 0.1-1.5 transfers per RACF bed/year. 5 Up to 60% of these presentations are subsequently admitted to hospital. 6,7 These ED presentations and hospital admissions can potentially be avoided by treating patients safely in the RACF. This can reduce incident delirium from entering a new environment, nosocomial infections, medication errors, pressure injuries, falls, and resource utilization. [8][9][10] In 2013, Bankstown-Lidcombe Hospital introduced a service improvement initiative supported by the hospital called the subacute geriatric outreach service (SGOS), where a geriatrician would visit RACFs to manage behavioral and psychological symptoms of dementia (BPSD) and follow up discharged patients who were admitted recently for acute medical conditions. This service had little impact on reducing ED presentations, so in 2015, Bankstown-Lidcombe Hospital introduced another service improvement initiative supported by the hospital called the acute geriatric outreach service (AGOS) that received referrals of acutely unwell patients from RACFs in the Bankstown catchment area. The AGOS geriatricians and nurse triage these referrals and visit RACFs to assess and manage patients there with "hospital in the home" interventions if possible.
We have previously shown that there was a decrease in the number of ED presentations from RACFs after the introduction of the AGOS. 11 However, data available at the time (1 June 2013 to 30 April 2017) could only demonstrate a trend toward a reduction in geriatric department hospital admissions from RACFs, likely due to lack of power from available sample size.

| Aims and hypothesis
We aim to determine if there is any change in the number of geriatric department hospital admissions from RACF after introduction of the AGOS by analyzing a larger data set (1 January 2010 to 31 December 2019). We hypothesize that this larger data set will yield a statistically significant reduction.

| Study design
We conducted an ITS analysis. There were three study periods.
The preintervention period is defined as the 41 months

Skin infections 26
Urinary catheter issues 20 Exacerbation of heart failure 17 Exacerbation of COPD 10 Abdominal pain 8 Other infections 6 BPSD 5

| Data Sources/Collection
We extracted variables from the AGOS database such as the demographics and acuity of a referral, conditions treated, and treatment outcome. We summarize this data using descriptive statistics to give a snapshot of service activity and case mix.
We obtained admissions data from our hospital's clinical information unit. They generated a list of all patients admitted to our geriatrics department from 1 January 2010 to 31 December 2019.
After excluding the data for 2015 (transitional period), there were 24,331 hospital admissions to our geriatric department during the study period.

| Population/Sample Size
There are currently 17 RACFs in the Bankstown catchment area.
Twelve of these were operational during the whole study period so they were included in the analysis, while the other five RACFs were excluded because they opened midway into the study (i.e. time varying confounders). The total number of beds in the 12 study RACFs was 1421 in 2012. This number grew over time to 1491 in 2019.

| Statistical Methods
We used independent t test to compare the means of each study period's monthly total number of admissions from RACFs, taking outliers into account. We performed negative binomial regression modeling for hospital admissions, adjusting for seasonality. We used STATA 16 (StataCorp) for statistical analysis.

| Summary of the AGOS Data
The  Since there was no coverage of our service on weekends, we performed another analysis that excluded weekend admissions from RACF. In this analysis, the independent t test also showed that following the establishment of the AGOS, there was a lower num- There was no evidence of seasonality (Figure 1). effect size in our current study could be explained by the fact that our service has matured over time, with a stronger referral base and a bigger sample size with adequate power.

| D ISCUSS I ON
Our findings are consistent with other RACF outreach services but the models vary. The other services are variably known as the "Geriatric Flying Squad," "Residential In-Reach," "Hospital in the Nursing Home (HINH)," and "RACF Hospital Avoidance Service." The South Care Geriatric Flying Squad is a RACF outreach service in Sydney, Australia with similar referral criteria and case mix. Compared to our AGOS, they're better equipped with por- Advisory Service (DBMAS). It is possible that increased activity from these other providers may have also contributed to a decline in the number of hospital admissions from RACF. A comparative ITS analysis, using admissions data from a neighboring local health district without a RACF outreach service for comparison, will better control for external confounders .

| CON CLUS ION
The results of our study support our hypothesis that the AGOS reduced hospital admissions. Future studies could better address external confounders by adopting a comparative interrupted time series design and expanding the AGOS database to include additional parameters.

CO N FLI C T O F I NTE R E S T
Nothing to declare.