- Title
- Economic evaluation of a pre-hospital protocol for patients with suspected acute stroke in Australia
- Creator
- Lahiry, Suman
- Relation
- University of Newcastle Research Higher Degree Thesis
- Resource Type
- thesis
- Date
- 2019
- Description
- Masters Research - Master of Philosophy (MPhil)
- Description
- Background: Although it is both preventable and treatable, stroke results in substantial economic burden in Australia and throughout the world. In Australia, stroke is the second leading cause of mortality after coronary heart disease and the leading cause of adult disability.(1, 2) Acute ischaemic stroke (AIS) is characterised by a sudden loss of blood circulation to an area of the brain, resulting in a corresponding loss of neurologic function and is caused by thrombotic or embolic occlusion of a cerebral artery.(3) AIS comprises 80 to 85 per cent of all strokes.(3, 4) For AIS management, time is brain, since for every minute treatment is delayed it is estimated that billions of neurons die.(5) AIS requires specialised management such as reperfusion by thrombolysis with intravenous recombinant tissue plasminogen activator (tPA) within the approved 4.5-hour window period.(6-8) Patients that are selected according to appropriate eligibility criteria and are treated with thrombolysis are at least 30 per cent more likely to have minimal to no disability at three months.(9) For AIS patients, the best patient outcomes are associated with the initiation of thrombolysis within the first 60 minutes after onset. In addition, several authors have demonstrated that treatment with tPA is cost-effective.(10-14) These findings support intensive efforts to organise stroke systems of care to optimise the timeliness of thrombolytic therapy in AIS.(10) Further, in routine clinical practice, using thrombolysis has been proven to be safe and effective, affording reductions in patient disabilities after stroke.(8) Consequently, national and international clinical guidelines recommend using thrombolysis in acute AIS management.(4, 15-17) Thus, AIS is a time-sensitive medical emergency and access to timely reperfusion by tPA for eligible AIS patients can reduce the vast economic burden imposed by stroke, decreasing time lapse and preventing death and disability as an important component of organised AIS management.(18-22) Although tPA has been licensed in Australia since 2003, implementation rates in the majority of hospitals are well below best-practice benchmarks.(23) Findings from the 2012 National Stroke Foundation clinical audit determined that only 7 per cent of ischaemic stroke patients received intravenous tPA in Australia.(23) Large parts of some states are reported to have no access, although the best-practice (Helsinki) hospital and population rates are 36 and 16 per cent, respectively.(23, 24) Evidence suggests that one of the greatest pre-admission barriers to accessing tPA is that patients’ presentation for treatment is often outside the therapeutic time.(23, 25, 26) In the Hunter region of New South Wales, Australia, a model of care was developed to address this problem. The aim of this model was to reduce the time between a stroke event and treatment at an appropriately resourced acute stroke centre. The model was designed to improve rates of tPA use among eligible stroke patients. The model was based on implementation of an ambulance protocol to reduce the time between a stroke event and treatment in an acute stroke unit (ASU).(27) The Pre-Hospital Acute Stroke Triage (PAST) was introduced (April, 2016) to allow ambulances attending patients with a suspected stroke to bypass closer hospitals that lacked specialised stroke facilities. Instead, ambulances transport the suspected stroke patient directly to the closest hospital with an ASU where tPA treatment could be given if appropriate.(28, 29) For patients experiencing AIS, evidence already exists for the effectiveness of models of care that aim to reduce the time between a stroke event and treatment in a suitably equipped hospital. Specifically, patient outcomes as measured by death and disability can be improved using paramedical pre-hospital triage and stroke screening tools, ambulance hospital bypass protocols, hospital notification of an arriving stroke patient, in-hospital acute stroke care, urgent stroke unit admission, an on-call multidisciplinary acute stroke team and urgent neuroimaging protocols.(30) Although a number of economic evaluation studies are published on stroke interventions, there are relatively few focused on the pre-hospital phase of stroke management. Economic evaluation of models of care in the health system is essential for planning the allocation of the limited health service resources required for growing societal needs. This evaluation provides useful information to decision-makers on the value of various healthcare investments. The resources required to implement the PAST protocol and its consequence, as measured in disability adjusted life years (DALYs), has not been previously explored. This study is a novel attempt to conduct an economic evaluation of the PAST protocol. This thesis explored the cost and consequence of implementing the PAST protocol. Specifically, the final outcome measure of DALYs was used to assess the effectiveness of the PAST protocol regarding the resources required for implementation. The discharge destination of AIS patients was reported, as this metric is a powerful predictor of final three-month global disability outcomes and a valid outcome measure for use in local and national quality improvement programs.(31) Aim: The primary aim of the research was to describe the cost-effectiveness of the PAST protocol implemented in alliance with a primary stroke centre (PSC) in regional New South Wales, Australia. Secondary aims were to measure, as a consequence of implementing the PAST protocol: i) the change in access to intravenous tPA, ii) patient health outcomes based on DALYs and iii) healthcare resource use. Materials and Methods: The PAST protocol was evaluated using observational data and a historical control design. Using aggregated administrative data, a decision analytic model was used to simulate costs and patient outcomes. During the implementation of the PAST protocol (the intervention), patient data were collected prospectively at the PSC. Control patients consisted of two groups: i) patients arriving at the PSC in the 12 months before PAST protocol implementation and ii) patients from the geographical catchment area of the smaller regional hospitals that were previously not bypassed during the control period. Control data were collected retrospectively. The periods for the observation of the control and intervention patients differed. The pre-intervention period occurred between 14 September 2005 and 31 August 2006. The intervention period started on 14 September 2006 and ran through to 30 October 2009. The data cleaning and analysis were done in January, 2018. The primary outcome of the economic evaluation was the additional cost per DALYs averted in the intervention period compared to the control period and has been derived for each arm informed by another study Model of Resource Utilisation, Costs and Outcomes for Stroke(32) and thus is an indirect comparison. A range of incremental cost-effectiveness ratio (ICER) has been provided in the model on basic one-way analysis for DALYs that could be added resulting in differences in total costs if use of tPA were increased (high estimate) or decreased (low estimate). Results: There were 364 patients in the historical control (median age: 76 years, 60% male) and 309 patients in the PAST cohort (median age 77 years, 61% male). Using the PAST protocol, patients were 17 times more likely to receive tPA (95% CI: 9.42–31.2, p<.05), with most associated costs incurred during acute care and rehabilitation. In the intervention group, it was estimated that 101.2 DALYs were averted related to the provision of tPA and stroke unit care compared to the estimated 7.9 DALYs averted in the combined control group. Overall, the intervention was associated with a net avoidance of 93.3 DALYs and appears to be cost-effective. The estimated cost per DALY averted per patient in the intervention group compared to the combined control group was $10,921 ($3421/[101.2 DALYs/309 patients] – [7.9 DALYs/551 patients]) across both the hospital and post-hospital phases of care. With base case unit prices, ICER was -10,921 for base case, -12,134 for worst case (assuming DALYs averted to be 10% less than base case) and -9,928 for the best case (assuming DALYs averted to be 10% less than base case). (Table G4.1) With low estimate unit prices, ICER was -20,439 for base case, -22,710 for worst case (assuming DALYs averted to be 10% less than base case) and -18,581 for the best case (assuming DALYs averted to be 10% less than base case). (Table G4.2) With high estimate unit prices, ICER was -8,581 for base case, -9,534 for worst case (assuming DALYs averted to be 10% less than base case) and -7,801 for the best case (assuming DALYs averted to be 10% less than base case). (Table G4.3) However, due to the missing information on the cause of death and NIHSS in cases of death in the Control group, further analyses was not possible. Considering ischaemic patients only, the intervention group had a mean National Institutes of Health Stroke Scale (NIHSS) of 14.11±6.64 compared to 8.28±5.76 in the control group (p<.01). NIHSS data for the alternate control pathway were not available. The difference between NIHSS scores of the intervention and historical control groups was 5.83, indicating that more severe patients were transferred to the PSC during the intervention period. Given the greater severity of stroke, a significantly greater proportion of patients in the intervention group died in hospital (22%) compared to the historical control group (8%, p<.05). The average time to death in the control group was greater than in the intervention group (p<.01). Conclusion: In this study, the implementation of the PAST protocol in regional Australia was found to be a cost-effective strategy to improve tPA implementation rates among eligible ischaemic stroke patients. The evidence indicates that for a modest increase in cost ($3421) per patient, there is a significant aversion of DALYs. To the researchers’ knowledge, this is the first Australian study to reveal the potential resource implications and patient outcomes of protocols designed to increase equitable access to tPA followed by care in stroke units among eligible ischaemic patients.
- Subject
- economic evaluation; pre-hospital protocol; acute stroke; Australia
- Identifier
- http://hdl.handle.net/1959.13/1408919
- Identifier
- uon:35903
- Rights
- Copyright 2019 Suman Lahiry
- Language
- eng
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