The OPEN ARCH Intervention
OPEN ARCH(Older Persons Enablement and Rehabilitation for Complex Health Conditions), provides comprehensive geriatric assessment and client enablement for community dwelling older persons with complex needs.
The intervention is delivered in the primary care setting and features collaboration between the client, treating GP, geriatric specialist and enablement officer (clinical nurse).
Service flow is illustrated in Fig. 1 (17). The OPEN ARCH model of care, study design, recruitment, participants, and data collection methods are described in detail elsewhere and summarised in the remainder of this methods Sect. (17, 18)
Trial design
The OPEN ARCH study is a multicentre randomised controlled trial with a stepped wedge cluster design. A stepped wedge trial has random and sequential crossover of clusters from control to intervention. At the first step all of clusters are in the control group, whereas at the end of the final step, all clusters are in the intervention group.
In our study, General practitioners (GPs) were the clusters, each contributing 1–9 participants (clients)to the study.
These were randomised at baseline to one of three intervention steps using a simple randomisation method. The step to which each cluster was assigned determined the start date of the intervention for that cluster, with a three-month time period between the commencement of each step. Step One included a three-month control period andnine months of intervention, Step Two a six-month control period and six months intervention, and Step Three included a control period of nine-months followed by three-months of intervention (Fig. 2).
The OPEN ARCH study received ethics approval from the Far North Queensland Human Research Ethic Committee, HREC/17/QCH/104–1174 and is registered on the Australian and New Zealand Trials Registry, ACTRN12617000198325p.
Detail of the trial design is provided in Kinchin et al 2018. (18)
Participants
Community dwelling persons over 70 years of age if non-Indigenous and over 50 years of age if Aboriginal and/or Torres Strait Islander (Indigenous) were eligible for OPEN ARCH. The lower age requirement for Indigenous participants aligns with Commonwealth Government recognition of the specific health needs of Indigenous persons and the associated eligibility threshold for aged care services (19).Older persons were not eligible if they were, under the care of a geriatrician, receiving a program of co-ordinated care (such as transition care program or nurse navigation), or had a cognitive deficit and no substitute decision maker.
Recruitment
General Practitioners provided the researchers with a deidentified list of those older personsin their care whom they determined through routine clinical assessmentas having complex needs.Using simple randomisation, the researchers selected up to 12 older persons from each GP who were then approached by their GP and provided verbal consent to be contacted by the OPEN ARCH team.
The Participant Information Form was provided to the participants during a face-to-face meeting with an OPEN ARCH team member prior to the provision of written consent.Participant recruitment was completed over a 7-week period.
Setting
The OPEN ARCH study was conducted with 14 GPs from 5 GP clinicsin the Cairns and Hinterland region. Two GP clinics were an Aboriginal and Community Controlled Health Organisation. Cairns is located in Far North Queensland, Australia. Theproportion of the Cairns population aged over 65 years is greater than the State average and Aboriginal and Torres Strait Islander persons comprise 14% of the population (compared to 4% across the State) (20). In 2014/215 the Cairns region had the highest rate of potentially preventable hospital admissions in the Queensland (20).
Outcome measures
The number of ED presentations and hospital admissions at the local public health service for each participant was provided by the Cairns and Hinterland Hospital and Health Service from routinely collected health service data within the Casemix data collection system (21). The time periods for these data comprised a three-month period prior to each individual’s baseline collection of study measures (i.e. Window 1) and successive three-month periods (i.e. Windows 2–4) prior to each subsequent collection of study measures. For admitted patient data, admissions for blood transfusions and renal dialysis were excluded. Inpatient stays that involved a transfer between wards were combined to create a single episode of care.
Potentially Preventable Hospitalisations (PPHs) were flagged based on primary and secondary International Statistical Classification of Diseases and Related Health Problems, Tenth Revision, Australian Modification (ICD-10-AM) codes. (22)A PPH was identified if the ICD-10-AM codes met the criteria defined in the Australian Institute of Health and Welfare National Healthcare Agreement: PI 18–Selected potentially preventable hospitalisations, 2018. (23) The PPHs were broadly categorised as Vaccine Preventable, Chronic or Acute, although subcategories were also created (e.g. Pneumonia and influenza, vaccinepreventable).
Sample size
This study aimed for a sample size of 120 participants as outlined in the published study protocol,
to provide 80% power anddetect a 9% difference (effect size) in service utilisationwith statistical significance at the 5% level. (18)Of the participants identified by their GP as meeting eligibility criteria,92 were randomly selected and invited to participate.
Following enrolment, 12 participants were removed from the study due to withdrawing consent (n = 7), commencing support through a separate enhanced care service (n = 4) and changing GP (n = 1).A total of 80 participants commenced the OPEN ARCH study.
Blinding
No blinding was undertaken. GPs and patients were required to make an informed decision for consent so had full disclosure of the intervention and the study design. To determine and compare pre- and post-intervention periods for each participant the intervention status was known.
Statistical methods
The distribution of demographic characteristics, caring status and living situation was compared between Steps at each time window. Age in years, as a median, was compared using Kruskal Wallis H-tests, while categorical variables were compared using Chi Square analyses.
Presentations to the ED and admissions to hospital were count data. Person days in the study was the number of participants, multiplied by the number of days in the study during each time window For example Window 1 was the 90 days prior to baseline data collection, Window 2 was the subsequent 90 days etc. This was calculated as a total for each GP cluster and time window. In cases where an individual had a hospital separation and/or ED presentation, the length of stay for these events was subtracted from their person days in the study.
The incidence rate of ED presentations and hospital separations were calculated as the number of events divided by the participant days in the study, multiplied by 1,000.
Rates were compared between Steps using the STATA ‘iri’ function, which calculates point estimates and confidence intervals for incidence-rate ratios.
To determine the effect of the intervention, after accounting for differences between the Steps, the OPEN ARCH data were transformed into long format by time window and analysed with multilevel mixed-effects Poisson regression modelsusing the STATA ‘meqrpossion’ function.ED presentationsand hospital separationswere analysed using separate models, each of which had three iterations. The first unadjusted model (Model 1) consisted of a dependent variable (e.g. number of ED presentations) and intervention status (i.e. intervention or control) as the independent variable, with random effects for Step, Cluster and individual. This model was then adjusted for time window (Model 2) to determine whether there were any changes across timeand then adjusted for demographics (Model 3), to account for the differences in patient characteristics between Steps. These mixed effects models were undertaken using an ‘Intention to Treat’ approach, which assumed that the OPEN ARCH intervention had an immediate effect on rates. For participants in Step 1 for example, events during Window 1 were considered as occurring during a control period and events in Window 2 as during an intervention period. As there was likely a delayed benefit of the intervention, the mixed effects modelling was also undertaken using a ‘pragmatic’ approach. In this approach, the first window after the intervention commenced was also coded as a control period. In this case, for Step 1, events during both Window 1 and Window 2 were therefore considered as occurring during the control period and Window 3 represented the first intervention period.
All analyses were undertaken using STATA 14 (StataCorp. 2015. Stata Statistical Software: Release 14. College Station, TX: StataCorp LP) and significance was set at 0.05