Long-term trends in incidence and risk factors for ischaemic stroke subtypes: Prospective population study of the South London Stroke Register

Abstract

BackgroundAs the average life expectancy increases, more people are predicted to have strokes. Recent studies have shown an increasing incidence in certain types of cerebral infarction. We aimed to estimate time trends in incidence, prior risk factors, and use of preventive treatments for ischaemic stroke (IS) aetiological subtypes and to ascertain any demographic disparities.Methods and findingsPopulation-based data from the South London Stroke Register (SLSR) between 2000 and 2015 were studied. IS was classified, based on the underlying mechanism, into large-artery atherosclerosis (LAA), cardio-embolism (CE), small-vessel occlusion (SVO), other determined aetiologies (OTH), and undetermined aetiologies (UND). After calculation of age-, sex-, and ethnicity-specific incidence rates by subtype for the 16-year period, we analysed trends using Cochran-Armitage tests, Poisson regression models, and locally estimated scatterplot smoothers (loess). A total of 3,088 patients with first IS were registered. Between 2000–2003 and 2012–2015, the age-adjusted incidence of IS decreased by 43% from 137.3 to 78.4/100,000/year (incidence rate ratio [IRR] 0.57, 95% CI 0.5–0.64). Significant declines were observed in all subtypes, particularly in SVO (37.4–18; p < 0.0001) and less in CE (39.3–25; p < 0.0001). Reductions were recorded in males and females, younger (<55 years old) and older (≥55 years old) individuals, and white and black ethnic groups, though not significantly in the latter (144.6–116.2; p = 0.31 for IS). A 4-fold increase in prior-to-stroke use of statins was found (adjusted odds ratio [OR] 4.39, 95% CI 3.29–5.86), and despite the increasing prevalence of hypertension (OR 1.54, 95% CI 1.21–1.96) and atrial fibrillation (OR 1.7, 95% CI 1.22–2.36), preventive use of antihypertensive and antiplatelet drugs was declining. A smaller number of participants in certain subgroup-specific analyses (e.g., black ethnicity and LAA subtype) could have limited the power to identify significant trends.ConclusionsThe incidence of ISs has been declining since 2000 in all age groups but to a lesser extent in the black population. The reported changes in medication use are unlikely to fully explain the reduction in stroke incidence; however, innovative prevention strategies and better management of risk factors may contribute further reduction.

Population-based stroke surveillance using Big Data: epidemiological trends in admissions and mortality in Australia

“…Here and elsewhere, 30,[32][33][34][35]37,38 trends differed according to age when analysing individual age bands; however, we found no evidence that trends differed according to age when assessed using interaction terms. Analysis of individual age-bands is more susceptible to random variation, particularly in younger age-groups with relatively fewer cases, therefore such results should be interpreted cautiously.…”

“…Several studies have demonstrated recent declines in stroke rates and mortality, although this experience is not universal. [30][31][32][33][34][35][36][37][38][39] Two studies utilising administrative data from England 30 and Sweden 31 While neither study included subarachnoid haemorrhage nor reported statistics separately for intracerebral and ischaemic stroke, both reported reductions in stroke incidence and mortality. Our finding of unchanged risk of subarachnoid haemorrhage and declining mortality corroborates other findings.…”

Long-term trends in death and dependence after ischaemic strokes: A retrospective cohort study using the South London Stroke Register (SLSR)

“…Increasing emphasis has been put on measures to improve cardiovascular health at the individual and community levels [46], including smoking cessation programs and lower target levels of cholesterol and blood pressure. We have previously demonstrated increasing use of statins in our study population [36]. These agents may have beneficial effects beyond their impact on incidence and risk factors and may contribute to lower IS severity and lower subsequent morbidity and mortality [47].…”

“…https://doi.org/10.1371/journal.pmed.1003048.g002 (Table 3). Using a conservative estimate of 52,000 incident ISs per year in the UK [36], we estimate additional survival beyond 30 days and 1 year of 3,200 and 6,300 patients, respectively (based on 6.2% and 12.1% absolute improvements in the adjusted 30-day and 1-year CFRs). We also estimate aversion of more than 3,200 cases of significant disability among those who…”

Long-Term Trends in Ischemic Stroke Incidence and Risk Factors: Perspectives from an Asian Stroke Registry

“…Our finding of a significant decrease in the overall incidence of AIS across a 12-year period from 2005 to 2016 is consistent with studies done in non-Asian and less heterogeneous populations. 2 This decrease can be attributed, in part, to reductions in the prevalence of smoking and diabetes, both being common risk factors for AIS, especially in Asia. 5 These trends are encouraging and worth further exploration to understand how stroke incidence can be further reduced, especially amongst Malays, which has seen an increase in incidence.…”