Title: Understanding clinicians’ decisions to offer intravenous thrombolytic treatment to patients with acute ischaemic stroke: a discrete choice experiment
Funder: Department of Health (England)

Abstract: Background: Intravenous thrombolysis is the most effective emergency treatment for acute ischaemic stroke and has been recommended by NICE since 2007. Despite considerable evidence for the effectiveness in well defined patient groups variation exists in uptake in the UK. Service limitations initially accounted for much of the variation in thrombolytic treatment rates between centres however with the introduction of 24 hours a day 7 days a week hyperacute stroke services the issue has shifted. Variation is likely to be accounted for not only by clinicians’ failure to adhere to guideline recommendations but also by the marked uncertainty surrounding benefit for individual patients within the grey zone (i.e. the upper and lower extremes of relative contraindications for treatment). Thus clinicians’ views are now a major influence on whom is offered treatment. Suggested explanations for this include the perceived balance between the benefits of treatment and the risks of intracranial haemorrhage but it remains unclear which patient and/or clinician factors influence treatment decisions inside and outside of the recommended clinical criteria based upon trial evidence. Aim: To explore variation in and identify the factors influencing clinicians’ decision making about intravenous thrombolysis for patients with acute ischaemic stroke given what is already known about the most effective and safe use of the treatment.Design and rationale: To understand the factors that influence decision making about thrombolysis we need to understand the thought processes of clinicians who are making these decisions in a way that reflects decision making in praxis. We also need to understand the relative importance of the range of possible factors which influence decision making about thrombolysis by quantifying the trade-offs that are made. A discrete choice experiment (DCE) will be conducted to understand which factors are important to the deliberations that clinicians make when considering offering thrombolysis to patients. DCEs are the method of choice to explore the relative importance of different (and sometimes implicit) factors within a decision making model which are not easily captured using more traditional approaches such as survey methods or observation. After semi-structured interviews to develop the content of an online survey stroke physicians and neurologists will be asked to state whether they would offer thrombolysis when given hypothetical patient vignettes which will vary in terms of patient characteristics (attributes e.g. age) and the magnitude of these characteristics (levels e.g. patient age 60 or 75 years). The relative importance of different attributes (and levels) to the decision will then be quantified and the estimated choice model used to predict the probability of offering thrombolysis given certain characteristics of the patient and the clinician. By understanding how clinicians negotiate the often difficult trade-offs between risks and benefits in different patients we can optimise appropriate use of thrombolysis and better support risk communication consent and decision-making with patients. Study findings will be used to inform strategies to reduce unwarranted variation in thrombolysis rates with tangible benefits in terms of improved stroke patient care and likely costs savings associated with optimal use through prevention of dependency. Plan of investigation:(i) Establish factors influencing decision making (determine attributes/characteristics and levels/the magnitude of these characteristics): Semi-structured interviews will be undertaken with clinicians with varying levels of experience of thrombolysis (up to ten) and existing qualitative data from interviews with stroke clinicians as well as relevant literature will be drawn upon to understand the full range of factors influencing decision making about thrombolysis. (ii) Create clinical scenarios (experimental design): A fractional factorial experimental design will combine the attributes and levels to construct hypothetical patient vignettes. The DCE will be presented in the form of vignettes to reduce cognitive burden; this narrative approach is more familiar for clinicians and therefore more engaging. The DCE will be translated into an online survey with questions also included on possible covariates such as clinician age experience of thrombolysis experience of patient intracranial haemorrhage and personality type/risk aversion.(iii) Survey Development: The DCE will be programmed into an outsourced online survey to enhance ease and speed of survey dissemination.(iv) Pilot DCE: The online DCE survey will be pre-tested with a convenience sample of 8-10 clinicians to establish the credibility of the vignettes examine participants’ understanding and to check timings. Pretesting will include a think aloud approach using a subset of vignettes to facilitate adaptation of the survey instrument.(v) Data collection: Stroke physicians and emergency medicine specialists will be recruited from across the UK. The online survey will be administered with reminders at two and four months.(vi) Analysis: The choice data will be modelled in a random utility theory framework using limited dependent variable modelling with data regressed on the attributes of the decision and characteristics of the decision makers accounting for both observed and unobserved heterogeneity.(vii) Dissemination of findings and translation into practice: The findings will be used to influence clinicians’ behaviour by: a) translating learning into regional professional development opportunities locally and nationally; b) supporting implementation of an existing decision support tool; c) informing clinical audit and evaluation programmes.


Research activity codes: 7.3 MANAGEMENT AND DECISION MAKING
Health categories: CARDIOVASCULAR