As the stroke community continues to construct a greater understanding of the various factors that influence patient outcomes, many have called for more nuanced alternatives to the modified Rankin scale (mRS) and other longstanding metrics that are regularly deployed in clinical studies as well as routine care. Recently, a team led by Canadian researchers—including Mayank Goyal, Aravind Ganesh (both University of Calgary, Calgary, Canada) and Nishita Singh (University of Manitoba, Winnipeg, Canada)—has proposed two scoring systems intended to more effectively capture the breadth of outcomes experienced by patients across the full spectrum of stroke.
Published earlier this year based on a narrative evidence review in the Journal of NeuroInterventional Surgery (JNIS), the proposed ELAN score integrates six variables: cognition, pre-existing disability/frailty, comorbidities, mental health, social support, and financial situation. Mental health and social support are attributed scores of 0–1, while the remaining factors are graded 0–2, providing an overall score out of 10.
Outlining the backdrop to this new approach, the authors posit that determinants of outcomes are now understood to extend well beyond traditional metrics—including National Institutes of Health stroke scale (NIHSS) score at presentation, infarct volume, occlusion location and quality of recanalisation—that stem from viewing patient prognostication through a ‘stroke lens’. As such, they advocate the more explicit consideration of biomedical and biopsychosocial factors.
The authors state in their JNIS paper that, despite recent advances in acute stroke management, “clinicians and families alike are often struck by the disconnect between radiographic findings and functional recovery”.
“The pooled HERMES analysis of EVT [endovascular therapy] trials demonstrated that, while reperfusion is strongly associated with improved mRS scores, many patients with technically successful reperfusion fail to achieve independence,” they continue. “Similarly, patients with identical ASPECTS [Alberta stroke programme early computed tomography score] and occlusion status at baseline may have dramatically different long-term trajectories. One in eight patients with small post-treatment infarct volumes nevertheless has poor functional outcomes. These gaps underscore the limits of anatomical and physiological predictors alone. Beyond biological factors, recovery is increasingly recognised to be shaped by cognitive reserve, functional vulnerability, mental health, social support and socioeconomic context.”
The authors also aver that, while age is a “powerful predictor” of stroke outcomes, “it is not perfect”, adding that chronological age “masks heterogeneity”. In their view, understanding prognosis therefore likely requires shifting from age alone to “a vitality- and context-based framework”.
In their paper, the authors attempt to weigh the importance of clinical discretion versus structured scoring of stroke outcomes as well—writing that “clinician ‘gestalt’ is indispensable in acute care, yet intuitive judgments are variable and susceptible to bias”—before noting that future studies comparing the two are “essential” to defining an optimal balance between speed and precision.
Based on the synthesis of evidence outlined in their JNIS paper, the authors present the aforementioned ELAN score—specifying that this new metric is currently intended for prospective validation rather than immediate clinical deployment, with the aim of guiding structured data collection and future substantiation efforts as opposed to representing a finalised scoring system or fixed set of weights.
In their view, the next “critical step” is prospective validation spanning diverse healthcare environments—extending beyond single-country or single-system studies, as there is likely to be variability across differing geographies, medical financing models, and social norms—with formal modelling being warranted to determine how the individual components of ELAN interact with each other as well as with traditional biological predictors. Contextual prognostication frameworks, the authors add, should be “adaptable rather than rigid”. With this in mind, they plan to initiate a worldwide study evaluating the ELAN scoring system in the near future.
“Our initial international ELAN survey showed that clinicians consistently recognise that factors beyond the stroke itself shape expectations of recovery and adaptation,” Singh states, speaking with NeuroNews. “The critical next step is to determine whether these perceptions translate into real-world outcomes. We have therefore launched a prospective, multicentre international study that will validate ELAN against established domain-specific measures and 90-day patient outcomes across diverse healthcare settings. The study will also help refine the score and determine data-driven weighting of its components. We welcome additional international centres and investigators interested in participating in the ELAN validation study.”
Additionally, last year, a broader research team also including Goyal, Ganesh and Singh shared the findings of a study intended to assess the inter- and intra-rater reliability of COSMOS—a novel outcome measure that they believe could help overcome the limitations of mRS scoring in patients with minor strokes.
Writing in Stroke, they state: “The vast majority of patients with minor stroke achieve what are considered good or excellent outcomes on mRS, yet many are dissatisfied with their outcomes. There is a need for a functional outcome measure tailored for minor stroke that better reflects the spectrum of clinical outcomes within this population.”
COSMOS consists of seven grades ranging from complete recovery (0) to loss of independence for an instrumental or basic activity of daily living, or worse (6). However, via its intermediary grades from 1–5, COSMOS also goes beyond activities of daily living, accounting for performance limitations and losses of a person’s hobbies or passions, and of their employment, educational, service or caregiving pursuits.
The study published in Stroke saw researchers develop a total of 100 test case vignettes, with stroke physicians, fellows, and research nurses and staff, being invited to review training materials and provide a grade for 20 cases representing the full range of COSMOS scores. After a minimum wash-out period of two weeks, they were asked to grade the same 20 cases again. The study ultimately showed that—among 33 participants with a median of 12.5 years of experience—COSMOS achieved substantial inter-rater reliability (80.5% agreement) and “almost-perfect” overall intra-rater reliability (87.1% agreement), with weighted Cohen’s kappa measurements finding almost-perfect agreement for both inter- and intra-rater reliability too. Similarly positive results were also seen when considering key subgroups based on the raters’ positions and duration of experience.
The authors caveat this success by noting that future research remains key, as COSMOS’s reliance on patient-reported challenges may mean the system is vulnerable to fluctuations in mental health, or to varying accounts of pre- versus post-stroke functioning. As such, future cohort studies “should also investigate the stability of COSMOS scores over time”. Ongoing efforts are also evaluating how COSMOS interacts with other clinical or patient-reported outcome measures; the scale is currently being deployed as either a secondary or tertiary outcome measure across a total of five global trials involving minor stroke patients. Furthermore, training for structured interviewing of raters has already been developed to expand its availability for less experienced clinicians.
“An exciting testament to the value added by these new measures is that they are already being embedded in various international collaborations,” Ganesh tells NeuroNews. “For example, COSMOS is being used in multiple ongoing stroke RCTs [randomised controlled trials], aided by our creation of the COSMOS Structured Interview—CSI-Stroke—and a certification module through Let’s Get Proof to permit standardised assessment. CSI-Stroke in turn has been translated into Mandarin and Norwegian for further validation of this patient-centred outcome. We encourage anyone interested to reach out to us!”
