Abstract Details

Title Re-analysis of Acute Stroke Trials Using Utility-weighted Modified Rankin Scales

Topic Cerebrovascular Disease and Interventional Neurology

Presentation(s) S37 - Stroke Epidemiology: Risk Factors, Incidence, and Unique Populations (1:00 PM-1:12 PM)

Poster/Presentation
Number 001

Objective

To characterize the between-study variability in utility weighting of the modified Rankin Scale (UW-mRS) in a stroke population and its implications for interpreting the results of clinical trials with a UW-mRS endpoint.

Background The EuroQol-5 (EQ-5D) is a health utility score that allocates a value reflecting the spectrum between perfect health (1), death (0) and outcomes worse than death (<0). A UW-mRS, where health utility weights are mapped to mRS levels, has been proposed as a “patient-centered” alternative primary outcome to the mRS. However, weighting may vary depending on specific study cohorts. We performed a systematic review to identify study-specific UW-mRS values and used these to re-analyze the results of major acute stroke trials.

Design/Methods We reviewed Medline, Embase, and PsychINFO (1987-2019) for EQ-5D based utility weights mapped to the mRS. We converted the primary outcome-timepoint mRS score of eighteen acute stroke trials to the UW-mRS values identified in our review. Trials selected had an mRS-based primary outcome and were discussed in US and/or Canadian best practice guidelines for acute ischemic stroke. A “positive” trial was defined with p<0.05.

Results Nine studies (n=10,708) reporting a UW-mRS were identified for inclusion. Mean (95% CIs) UW-mRS were: mRS 0=0.93 (0.96, 0.90), 1=0.86 (0.89, 0.83), 2=0.68 (0.72, 0.64), 3=0.57 (0.61, 0.53), 4=0.31 (0.35, 0.26) and 5=0.06 (0.12, 0.00). When applied to the eighteen acute stroke trials, three (17%) had an unstable outcome (e.g. positive versus neutral result) depending on the UW-mRS scale used.

Conclusions Multiple factors, including cohort-specific characteristics, can affect utility-weighting of the mRS. If the UW-mRS is selected as a primary outcome, the approach to weighting may affect the results of a clinical trial. Researchers using the UW-mRS should establish a trial-specific UW-mRS or consider simply reporting both the mRS and health utility scale as separate co-primary outcomes.

Authors/Disclosures
Alexander Rebchuk, MD, MSc PRESENTER	Dr. Rebchuk has nothing to disclose.
	No disclosure on file
	No disclosure on file
Michael D. Hill, MD (University of Calgary)	Dr. Hill has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Boehringer Ingelheim. Dr. Hill has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Sun Pharma. Dr. Hill has received stock or an ownership interest from Circle Neurovascular.
Thalia S. Field, MD (University of British Columbia)	Dr. Field has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Bayer. Dr. Field has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Novartis. Dr. Field has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for AstraZeneca. Dr. Field has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for AstraZeneca. Dr. Field has received personal compensation in the range of $5,000-$9,999 for serving as an Expert Witness for Canadian Medical Protective Association, plaintiff. The institution of Dr. Field has received research support from Heart and Stroke Foundation, Brain Canada and CIHR. Dr. Field has a non-compensated relationship as a Editorial board with Stroke that is relevant to AAN interests or activities. Dr. Field has a non-compensated relationship as a Editorial board with CJNS that is relevant to AAN interests or activities. Dr. Field has a non-compensated relationship as a Editorial board with JNNP that is relevant to AAN interests or activities. Dr. Field has a non-compensated relationship as a Board member with DESTINE Health that is relevant to AAN interests or activities. Dr. Field has a non-compensated relationship as a Board Member with Vancouver General Hospital Foundation that is relevant to AAN interests or activities.

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