Functional outcome after ischaemic stroke and intracerebral haemorrhage from two national cohorts

Background Outcome of acute ischaemic stroke (AIS) improved considerably through intravenous thrombolysis (IVT) and endovascular therapy (EVT), while treatment options for intracerebral haemorrhage (ICH) remained limited. We compared functional outcome 3 months after AIS and ICH in contemporary patients from two national stroke registries. Methods This is a pooled analysis of the prospective Swiss and Norwegian Stroke Registries. We enrolled all patients with AIS and ICH between 2014 and 2022/2023. The primary outcome was favourable functional outcome (modified Rankin Scale 0–2) at 3 months. Results We included 111 038 patients: 98 354 patients with AIS (21 946/22.4% patients received IVT and 8270/8.4% patients received EVT) and 12 684 patients with ICH. Baseline National Institutes of Health Stroke Scale (NIHSS) was higher in patients with ICH (AIS: median 3, IQR 1–7 vs ICH median 7, IQR 2–15). Overall, 64 135 patients with AIS (65.2%) and 4620 patients with ICH (36.4%) had a favourable functional outcome. ICH was independently associated with poor outcome (adjusted OR (aOR) for favourable functional outcome: 0.42, 95% CI 0.39 to 0.45, p<0.001). Sensitivity analysis excluding patients receiving IVT/EVT confirmed the finding with attenuated magnitude (aOR 0.61, 95% CI 0.56 to 0.66, p<0.001). GSEM analysis found a significant negative direct (β-coefficient −0.77) and indirect effect of ICH on outcome. The indirect effect was mediated through higher baseline NIHSS (β-coefficient=+4.55) and availability of IVT/EVT for AIS (β-coefficient=−21.74 and −22.11, respectively). Overall, the effect of ICH on outcome was split between direct (47%) and indirect (53%) effects. Conclusion Functional outcome after ICH is worse compared with AIS. Measured clinical mediators only partly explain the differences and unmeasured overall care directions (ie, care limitations) may have contributed.