Stroke in Sierra Leone: Case fatality rate and functional outcome after stroke in Freetown

Abstract

Background: There is limited information on long term outcomes after stroke in Sub-Saharan Africa (SSA). Current estimates of case fatality rate (CFR) in SSA are based on small sample sizes with varying study design and report high heterogeneity. Aims: We report CFR and functional outcomes from a large, prospective, longitudinal cohort of stroke patients in Sierra Leone and describe factors associated with mortality and functional outcome. Methods: A prospective longitudinal stroke register was established at both adult tertiary government hospitals in Freetown, Sierra Leone. It recruited all patients ≥18 years with stroke, using the World Health Organization definition, from May 2019 until October 2021. To reduce selection bias onto the register all investigations were paid by the funder and outreach conducted to raise awareness of the study. Sociodemographic data, National Institute of Health Stroke Scale (NIHSS) and Barthel Index (BI) was collected on all patients on admission, at seven days, 90 days, one year and two years post stroke. Cox proportional-hazards models were constructed to identify factors associated with all-cause mortality. A binomial logistic regression model reports odds ratio (OR) for functional independence at one year. Results: 986 patients with stroke were included, of which 847 (85.9%) received neuroimaging. Follow up rate was 81.5% at one year, missing item data was <1% for most variables. Stroke cases were equally split by sex and mean age was 58.9 (SD: 14.0) years. 625 (63%) were ischaemic, 206 (21%) primary intracerebral haemorrhage, 25 (3%) subarachnoid haemorrhage and 130 (13%) were of undetermined stroke type. Median NIHSS was 16 (9-24). CFR at 30 days, 90 days, 1 year and 2 years was 37.1%, 44.4%, 49.7% and 53.2% respectively. Factors associated with increased fatality were male sex HR:1.28 (1.05-1.56), previous stroke HR:1.34 (1.04-1.71), atrial fibrillation HR:1.58(1.06-2.34), subarachnoid haemorrhage HR:2.31 (1.40-3.81), undetermined stroke type HR: 3.18(2.44-4.14) and in-hospital complications HR: 1.65 (1.36-1.98). 93% of patients were completely independent prior to their stroke, declining to 19% at one year after stroke. Functional improvement was most likely to occur between 7 and 90-days post stroke with 35% patients improving, and 13% improving between 90 days to one year. Increasing age OR: 0.97(0.95-0.99), previous stroke OR: 0.50 (0.26-0.98), NIHSS OR 0.89 (0.86-0.91), undetermined stroke type OR:0.18 (0.05-0.62) and ≥1 in hospital complication OR:0.52 (0.34-0.80) were associated with lower OR of functional independence at one year. Whilst hypertension OR:1.98 (1.14-3.44) and being the primary breadwinner of the household OR:1.59 (1.01-2.49) were associated with functional independence. Discussion: Stroke in Sierra Leone affected younger people, and resulted in high rates of fatality and functional impairment relative to global averages. Key clinical priorities for reducing fatality include preventing stroke-related complications through evidence-based stroke care; improved detection and management of atrial fibrillation, and increasing coverage of secondary prevention. Further research into care pathways and interventions to encourage care seeking for less severe strokes should be prioritized. Data availability: Requests for access to anonymized data for academic use should be made to the SISLE team https://www.kcl.ac.uk/research/stroke.