Rethinking favorable outcomes: "return to baseline" as an additional outcome in ischemic stroke
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Julia-Laura Schulz1, Arno Reich2, Charlotte S Weyland1
1Department of Diagnostic and Interventional Neuroradiology, University Hospital RWTH Aachen, Aachen, Germany.
Background:
Stroke outcomes are commonly assessed using the modified Rankin Scale (mRS), dichotomized into "favorable" (0-2) and "unfavorable" (3-6). Many elderly patients present with pre-stroke mRS scores of 3-5, making "favorable" outcomes unattainable and complicating treatment evaluation.
Methods:
This is a monocentric, retrospective analysis of ischemic stroke patients in our prospective registry (2010-2022). Outcomes include mRS scores at discharge and 90 days post-stroke. Descriptive and inferential statistics were applied with appropriate tests for categorical and ordinal variables. Multivariable logistic regression was used to model return to pre-stroke mRS and death by 90 days, adjusted for pre-stroke mRS group, age, sex, NIHSS on admission, treatment modality and vascular territory. Statistical significance was defined as p < 0.05.
Results:
Of 3,724 ischemic stroke patients admitted, 2,070 met inclusion criteria (median age 75.7). Among those with favorable pre-stroke mRS (0-2, n = 1,827), 47.6% achieved favorable outcomes at discharge and 47.5% at 90 days. By definition, none with unfavorable pre-stroke mRS achieved favorable outcomes. At discharge, return to baseline mRS occurred in 16.2% with favorable pre-stroke mRS, compared to 19.3% with unfavorable (p = 0.216). 90 days post-stroke, return to baseline occurred in 21.8% with favorable pre-stroke mRS, compared to 11.9% with unfavorable (p < 0.001). Redefining favorable outcome to include return to pre-stroke mRS increased rates from 42.0 to 44.3% at discharge and from 41.9 to 43.3% 90 days post-stroke (p < 0.001). In multivariable analysis a pre-stroke mRS of 3-5 was associated with death by 90 days (OR 4.40, 95% CI 3.18-6.10) but not with return to baseline in all patients (OR 1.02, 95% CI 0.65-1.58); among survivors it was associated with a higher probability of return to baseline (OR 2.34, 95% CI 1.40-3.91).
Conclusion:
The traditional dichotomization of mRS does not reflect the wide range of pre-stroke status. Incorporating "return to pre-stroke mRS score" as a favorable outcome metric alongside the conventional dichotomy provides a more individualized measure, improving treatment evaluation and supporting tailored care strategies, particularly for patients with higher pre-stroke mRS scores.
