Rates, risks and routes to reduce vascular dementia (R4VaD), a UK-wide multicentre prospective observational cohort study of cognition after stroke: baseline data and statistical analysis plan (ISRCTN18274006)

BackgroundStroke is often followed by vascular cognitive impairment and vascular dementia; these are the most feared complication of stroke. However, there is limited understanding of post-stroke cognitive impairment. MethodsRates, Risks and Routes to Reduce Vascular Dementia (R4VaD) is an observational cohort study of post-stroke cognition. Patients with haemorrhagic or ischaemic stroke, or transient ischaemic attack, were recruited within six weeks of stroke from hospitals across the UK. Consent was obtained from patients with capacity or from relatives/friends in those without capacity. The primary outcome is cognition and its severity assessed using a 7-level ordinal outcome. Final cognition will be compared in those with mild stroke/TIA (worst NIHSS <=7) versus severe stroke (NIHSS >7). Secondary outcomes will include function, mood and quality of life. ResultsWe recruited 2441 patients from 50 hospitals. Of these, 2437 (99.8%) had a qualifying event of stroke or TIA. The mean age was 68.2 years (standard deviation 13.5), females 981 (40.3%), onset to recruitment 6 days [interquartile range 3-13] and diagnosis ICH 193 (7.9%), ischaemic stroke 2101 (86.2%), TIA 143 (5.9%). The distribution of cognition at baseline was: normal 1256 (51.6%), minor neurocognitive disorder-single domain 530 (21.8%), minor neurocognitive disorder-multi domain 320 (13.1%), major neurocognitive disorder-mild 237 (9.7%), major neurocognitive disorder-moderate 90 (3.7%) and major neurocognitive disorder-severe 3 (0.1%). We provide the statistical analysis plan in the appendix. ConclusionWe provide baseline data and the SAP. Final follow-up will be completed in quarter 2 2024. The data highlight the substantial under-appreciated cognitive burden of stroke, even in the first few days and weeks.