We aimed to study how the individual items of the National Institutes of Health Stroke Scale (NIHSS) at admission predict functional independence 3 months post-stroke in patients with first-ever stroke.

This registry-based study used data from two Swedish stroke registers (Riksstroke, the mandatory national quality register for stroke care in Sweden, and Väststroke, a local quality stroke register in Gothenburg).

This study included patients with first-ever acute stroke admitted from November 2014 to August 2018, with available NIHSS at admission and modified Rankin Scale (mRS) at 3-month follow-up.

The primary outcome variable was mRS≤1 (defined as an excellent outcome) at 3-month follow-up.

We included 1471 patients, mean age was 72 (± 14.5) years, 48% were female, and 66% had mild strokes (NIHSS≤3). In adjusted binary logistic regression analysis, the NIHSS items impaired right motor arm and leg, and impairment in visual field, reduced the odds of an excellent outcome at 3 months ((OR 0.60 (95% CI 0.37 to 0.98), OR 0.60 (95% CI 0.37 to 0.97), and OR 0.65 (95% CI 0.45 to 0.94)). When exploring the effect size of associations between NIHSS items and mRS≤1 p, orientation, language and right leg motor had the largest yet small association.

Stroke patients with scores on the NIHSS items right motor symptoms or visual field at admission are less likely to have an excellent outcome at 3 months. Clinicians should consider the NIHSS items affected, not only the total NIHSS score, both in treatment guidance and prognostics.