A prospective pre-post cohort study design was adopted to estimate the changes to hospital admission rates and length of stay in the 12 months pre and post-implementation of the EDDIE intervention in a 96 bed regional Australian RACF in June 2016. Participants included all residents within the facility over the study period. This represented a range of 91 to 96 residents, with an average monthly occupancy of 94 residents observed across both the pre and post EDDIE cohorts. We refer to residents present during the 12 months post implementation of the EDDIE intervention as the intervention cohort (June 2016 – May 2017), and residents present during the 12 months prior to the EDDIE interventions as the usual care cohort (June 2015 - May 2016). We used the CHEERS checklist as our reporting guide[30].
Individual patient demographic data were not collected from the RACF as part of this study. To inform the generalisability of our results we obtained key descriptive statistics about the population of aged care residents within the immediate geographic region from an administrative database [31]. These data indicate that across the 9 RACFs operating within the immediate geographic region in 2017, 65% of residents were female and over 50% were aged 85 and above. The average length of stay for patients who died in the facility was 37.8 months, and 48.5% of residents had a diagnosis of dementia. A detailed summary of the population characteristics is included in Additional File 1.
The intervention
The EDDIE program was developed to enable practice change and improvement so that deteriorating residents could be identified early and managed proactively within the RACF, reducing the need for transfer to hospital, or shortening length of stay. Importantly, the intervention did not involve the employment of additional nursing staff within the RACF. The focus was instead on upskilling existing staff members and empowering them to manage sub-acute episodes within the facility. In the context of this study, a sub-acute episode was defined as a scenario where a resident required more intensive treatments, interventions and/or frequent assessments for a complex condition that did not require immediate hospitalisation. This included conditions such as kidney infections, pneumonia and urinary tract infections where residents could be monitored using appropriate diagnostic equipment and treated with intra-venous antibiotics within the RACF. While existing nursing staff were qualified to manage sub-acute episodes within the facility, it had not been common practice until the implementation of the EDDIE program.
The intervention encompassed four core components:
- Advanced clinical skills training for all nursing and care staff: Training was mandatory and involved an initial face-to-face education session on the early identification of deterioration, and appropriate clinical response. Targeted training was also provided on clinical management of the eight conditions that had been identified as likely to result in avoidable hospitalisation: urinary tract infections, chest pain, falls, delirium, dehydration, dyspnoea, constipation, palliative care.
- Decision support: A decision support tool in the form of a flip chart was readily available to staff within the RACF, as well as in pocket-size books that staff could carry on their person. This tool reinforced the educational content and was structed around a ‘traffic light’ system where colour-coded parameters were established on assessment documentation to determine a change in health status, which then triggered further assessment and treatment. The traffic light tool included specific clinical decision making guidelines for managing acute deterioration across all eight conditions identified and addressed within the training (listed under point (1) above). A track and trigger tool was used to monitor vital signs. A standard communication approach (‘Situation, Background, Assessment, Recommendation’) was used for written and oral communication [32].
- Diagnostic medical equipment: Diagnostic equipment, not commonly found in the RACF setting, was introduced at the study site to support nursing staff to monitor residents at the early stages of deterioration. This included bladder scanners, ECG machines, vital signs monitors and pulse oximeters. Use of the equipment was covered in the mandatory face to face training sessions, with ongoing, on-the-job training opportunities with a nurse educator also available to staff.
- Specialist clinical support and collaboration, grounded in the principles of implementation science through the adoption of the i-PARiHS implementation framework[33]. This included a knowledgeable and enthusiastic on-site clinical leader; a number of clinical ‘champions’ to promote staff uptake and adoption; and, targeted engagement with external stakeholders including: General Practitioners and their practice nurses; nurse practitioners; hospital staff including geriatricians and emergency department staff; ambulance staff and residents’ families. Embedding of the program into business-as-usual practices was achieved through the development of clinical policies and procedures within the RACF to support the use of clinical decision support tools and program pathways.
Statistical analysis of the observed hospital admissions data
There was one hospital admission that occurred within the usual care period but where discharge occurred after EDDIE implementation. This admission was analysed as part of the usual care cohort in keeping with the EDDIE program’s focus on hospital avoidance. The impact on variation in the data was explored by fitting statistical distributions around key results based on the observed means and standard deviations from both intervention and usual care cohorts. A normal distribution provided the best fit for the number of admissions per annum. A gamma distribution was used to represent length of stay as its positive, right-skewed nature accounted for a small proportion of admissions experiencing relatively long lengths of stay.
Costs of implementation
A set of the initial implementation costs of EDDIE were estimated based on the project data collection. The decision support tool was developed and piloted in a previous study and the costs associated with this were not included in this analysis. We accounted for the cost of printing the decision support materials, as well as the staff costs associated with the implementation strategy such as training, stakeholder engagement and project management activities. Details of the time spent on these activities, as well as the numbers of type of staff members involved, were prospectively collected in an implementation activity log. The costs of staff time were assigned using published salary band data where available. These costs are reported in Additional File 2. Due to the one-off, upfront nature of these costs they were not included in the modelled analysis.
Modelled cost-effectiveness analysis
A Markov model was developed to estimate the cost-effectiveness of the EDDIE intervention compared to usual care over a period of 12 months. The model defined a number of discrete health states that aged care residents could experience over a period of 365 days including: time spent within the RACF as a stable resident; ‘sub-acute episodes’ involving management of resident deterioration within the RACF; hospital admissions; and death. A set of transition probabilities governed the likelihood of residents transitioning from one state to another at the end of each daily cycle. The Markov model structure is included in Additional File 3.
The model was used to synthesise data collected in the study with published literature on the outcomes associated with relevant health states experienced by residents. Cost-effectiveness was assessed by comparing the incremental differences in costs and quality adjusted life years (QALYs) for the intervention cohort relative to the usual care cohort. QALYs were derived by weighting the time spent in each health state by a health related utility associated with that state. Utilities are values that represent the strength of individuals’ preferences for different health states. They are anchored by a scale where a utility of zero is equivalent to death and a utility of 1 is equivalent to full health[34]. A period of 10 years spent in a health state with a utility of 0.6 would therefore represent 6 QALYs. The evaluation was conducted from the perspective of the Australian health care system in which aged care services and hospital admissions are publicly funded. All costs are reported in 2018 Australian dollars.
All probabilities, costs and utility values applied in the model, along with respective standard deviations and data sources where relevant, are reported in Table 1. Data collected prospectively throughout the study was used to populate probabilities of transitioning between the different health states in the model, and to assign the costs of equipment. RACF bed day costs, hospital costs and utility values were estimated from the published literature.
Table 1: Transition probabilities applied in the cost-effectiveness model
Parameters
|
Base case estimate
|
SD
|
Source
|
Transition probabilities:
|
|
|
|
Intervention cohort
|
|
|
|
Daily probability of sub-acute episode
|
0.003
|
0.007
|
Study data
|
Proportion of sub-acute episodes treated within the facility
|
0.670
|
0.388
|
Study data
|
Daily probability of sub-acute episodes admitted to hospital
|
0.722
|
0.288
|
Study data
|
Daily probability of residents being discharged from hospital
|
0.283
|
0.150
|
Study data
|
Usual care cohort
|
|
|
|
Daily probability of residents being admitted to hospital
|
0.001
|
0.004
|
Study data
|
Daily probability of residents being discharged from hospital
|
0.151
|
0.072
|
Study data
|
All residents
|
|
|
|
Daily probability of death
|
0.0011
|
0.0001
|
Study data
|
|
|
|
|
Costs
|
|
|
|
New diagnostic equipment (annualised)a
|
|
|
|
Bladder Scanner x1
|
1714
|
672
|
Study data
|
ECG Machine x1
|
351
|
138
|
Study data
|
Vital Signs Monitor x1
|
277
|
109
|
Study data
|
RACF bed day
|
194
|
76
|
[35]
|
Ambulance transfer to hospital
|
649
|
254
|
[36]
|
Hospital bed day
|
1807b
|
708
|
[14]
|
|
|
|
|
Utility values
|
|
|
|
RACF residents
|
0.514
|
0.252
|
[37]
|
Elderly inpatients admitted from RACF
|
0.44
|
0.4
|
[38]
|
RACF = residential aged care facility; SD = standard deviation; ECG = electrocardiogram
- Costs were annualised over a useful life of seven years according to Australian government depreciation schedules (Income Tax Assessment Act, Income Tax (Effective Life of Depreciating Assets) Determination 2015)
- Inflated to 2018 dollars using an index of hospital price inflation [39]
Transition probabilities were derived from the observed daily events data collected at the RACF over the period June 2015 - May 2016 for usual care and June 2016 – May 2017 for the EDDIE intervention.
Costing items included the cost of additional diagnostic equipment not typically utilised in the RACF setting that were purchased in order for trained staff to better detect and manage sub-acute episodes. Equipment costs were annualised over a period of seven years, reflecting their useful life as defined in the Australian government depreciation schedules[40]. A cost per day was assigned to RACF bed days based on current national fee schedules[35]. The cost of a hospital bed day was informed by a 2011 Australian study that produced estimates of admissions costs and length of stay that were specific to a RACF cohort[14]; this was then inflated to 2018 dollars using an index of hospital price inflation[39]. The cost of an ambulance transfer was also assigned with each hospital admission in line with standard practice[36].
The model assigned separate utility values according to whether a resident was in the RACF or in hospital.
Sensitivity analysis
A probabilistic sensitivity analysis was performed in order to estimate the impact of simultaneous uncertainty across all modelled estimates. A normal distribution was applied to cost parameters with a 95% confidence interval encompassing a variation of 20% above and below the base case estimate. The exception was the cost per hospital bed day which was assigned a gamma distribution (SD 1,028) based on the nature and availability of these data[14]. Beta distributions were fitted to the transition probability and utility estimates using the standard deviations reported in Table 1. A Monte Carlo simulation was then performed with 1,000 randomly drawn samples taken from each of the modelled parameter distributions.
The modelled uncertainty was represented in the form of a distribution around the Net Monetary Benefit (NMB) associated with a decision to adopt the EDDIE intervention. This provides a measure of the value of the intervention in monetary terms when the willingness to pay for a QALY is known. A positive NMB indicates that an intervention is cost-effective. The NMB was estimated using a recently published study of the optimal willingness to pay for a QALY in an Australian setting of $28,000[41]. A sensitivity analysis estimated the cost-effectiveness of the intervention where the willingness to pay for health benefits was set to zero.