Rethinking favorable outcomes: “return to baseline” as an additional outcome in ischemic stroke

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.