Background: Patients with acute stroke are at risk of respiratory or circulatory compromise resulting in vital instability, which can be captured through the widely used aggregated National Early Warning Score (NEWS). We aimed to assess the relation between vital instability (defined as NEWS of five or higher) and death or dependency at 90 days after stroke.
Methods: In this observational cohort study we studied 763 patients with ischaemic stroke (n = 400), intracerebral haemorrhage (ICH) (n = 146) or subarachnoid haemorrhage (SAH) (n = 217), hospitalized to a Dutch tertiary referral hospital from 1 January 2017 to 31 December 2018. We calculated NEWS for each 8 h time span during the first 72 h after hospitalization. We also decomposed NEWS into its three components respiration, circulation and consciousness. The primary outcome was death or dependency (modified Rankin Scale score ⩾3) at 90 days after stroke. The association of vital instability with functional dependency was examined using Poisson regression.
Results: Two hundred and twenty-seven (58%) patients with ischaemic stroke, 101 (69%) with ICH and 142 (65%) with SAH had at least one episode of vital instability. In patients with ischaemic stroke or SAH, vital instability was associated after adjustment for confounders with death or dependency (adjusted relative risk 1.55 ((95% CI) 1.25-1.93 and 2.13 (1.35-3.36), respectively)). This was mainly driven by impaired consciousness, which was associated with death or dependency in all types of stroke. Respiratory insufficiency and circulatory instability were associated with death or dependency only in SAH.
Conclusion: Vital instability in the first 72 h of hospitalization for ischaemic stroke or SAH is associated with death or dependency at 90 days. Impaired consciousness was the main driver of this relationship. NEWS may not be appropriate for patients with acute stroke, mainly due to the dichotomous manner in which the level of consciousness is classified, and modification of NEWS should be considered for these patients.
Keywords: NEWS; Stroke; functional outcome; intracerebral haemorrhage; ischaemic stroke; modified Rankin scale; mortality; subarachnoid haemorrhage; vital instability.