Functional trajectories between 90 days and 1 year after intracerebral haemorrhage: a Swedish Stroke Register (Riksstroke) study

Functional outcome after ICH is commonly assessed at 90 days, although recovery and deterioration may continue beyond this conventional endpoint. Large-scale data describing within-patient functional trajectories beyond 90 days remain limited.

We conducted a register-based cohort study using the Swedish Stroke Register (Riksstroke), including adults with ICH between 2017 and 2021. Prestroke-independent 90-day survivors with available mRS data at both 90 days and 1 year were included. Functional trajectories were classified as improved, unchanged, worsened or died according to transitions across grouped mRS categories (0-2, 3, 4, 5 and 6 [death]). Multivariable logistic regression identified predictors of worsening or death and improvement.

Among 13,574 patients with ICH, 8583 prestroke-independent patients fulfilled eligibility criteria. Of these, 4797 were alive with available 90-day mRS data, and 3030 had complete mRS assessments at both 90 days and 1 year and were included in the primary analysis. Between 90 days and 1 year, 21.5% improved, 67.6% remained unchanged, 5.2% worsened and 5.8% died. Recovery at 1 year was most frequent among patients with mRS 3 at 90 days, of whom 62.4% achieved mRS 0-2, whereas 92.8% of patients with mRS 0-2 remained in the same category. Among patients with mRS 4-5 at 90 days, 20.4% improved to mRS 0-3 by 1 year. Increasing age and higher 90-day disability were associated with less favourable trajectories, whereas male sex was associated with greater likelihood of improvement.

Among prestroke-independent 90-day survivors with complete functional follow-up, functional outcomes after ICH remained dynamic beyond 90 days, particularly among patients with moderate disability. Nearly two-thirds of patients with moderate disability at 90 days achieved mRS 0-2 by 1 year, whereas more than 9 in 10 patients who were already classified as mRS 0-2 remained so. These findings suggest that longer-term outcome assessment may provide additional clinically relevant information in future ICH studies and clinical trials.