Time trends in stroke incidence and modifiable risk factor prevalence in England (2018-2024): A record linkage population-based study.
Source: PubMed, NCBI / U.S. National Library of Medicine
The incidence of stroke at younger ages appears to be increasing, whilst it is falling at older ages. We aimed to determine the current trend and how it might have changed during and after the COVID-19 pandemic. We identified first-ever stroke events in adults in England between 1st April 2018 and 31st March 2024 through record-linkage with multiple overlapping sources including primary care, hospital admission, death certificate, and records from a stroke specific national audit. Standardised age-specific (age < 55 versus ≥ 55 years) stroke incidence was calculated and compared using incidence rate ratio (IRR) during three time periods (pre COVID-19 pandemic: 2018-2020; COVID-19 pandemic: 2020-2022 and post COVID-19 pandemic: 2022-2024). We quantified the age-specific divergence using the Relative Temporal Rate Ratio (RTTR). Diagnosis and treatment of modifiable stroke risk factors (hypertension, diabetes, atrial fibrillation, and hyperlipidaemia) before and after the stroke were also compared across the study periods. Analyses were stratified by sex, ethnicity, deprivation, regions, and stroke subtypes. 643,885 incident strokes were included (2018-2020: 206,290; 2020-2022: 211,420; and 2022-2024: 226,175). At age < 55 years, there was a significant increase of stroke incidence during the pandemic (2020-2022 versus 2018-2020: IRR = 1.07, 95%CI [1.05,1.09], p < 0.001), which was consistent by sex, ethnicity, deprivation,
Abstract
The incidence of stroke at younger ages appears to be increasing, whilst it is falling at older ages. We aimed to determine the current trend and how it might have changed during and after the COVID-19 pandemic. We identified first-ever stroke events in adults in England between 1st April 2018 and 31st March 2024 through record-linkage with multiple overlapping sources including primary care, hospital admission, death certificate, and records from a stroke specific national audit. Standardised age-specific (age < 55 versus ≥ 55 years) stroke incidence was calculated and compared using incidence rate ratio (IRR) during three time periods (pre COVID-19 pandemic: 2018-2020; COVID-19 pandemic: 2020-2022 and post COVID-19 pandemic: 2022-2024). We quantified the age-specific divergence using the Relative Temporal Rate Ratio (RTTR). Diagnosis and treatment of modifiable stroke risk factors (hypertension, diabetes, atrial fibrillation, and hyperlipidaemia) before and after the stroke were also compared across the study periods. Analyses were stratified by sex, ethnicity, deprivation, regions, and stroke subtypes. 643,885 incident strokes were included (2018-2020: 206,290; 2020-2022: 211,420; and 2022-2024: 226,175). At age < 55 years, there was a significant increase of stroke incidence during the pandemic (2020-2022 versus 2018-2020: IRR = 1.07, 95%CI [1.05,1.09], p < 0.001), which was consistent by sex, ethnicity, deprivation, stroke subtype and region, and was most prominent for ethnic minority groups (Black: IRR = 1.13, 95%CI [1.05,1.21], p = 0.0005; Asian: IRR = 1.26, 95%CI [1.20,1.33], p < 0.001). This trend continued after the pandemic (2022-2024 vs. 2020-2022: IRR = 1.04, 95%CI [1.02,1.06], p < 0.001). On the contrary, stroke incidence at age ≥ 55 remained stable during the pandemic (IRR = 0.99, 95%CI [0.99,1.00], p = 0.06), and increased afterwards (IRR = 1.04, 95%CI [1.03,1.04], p < 0.001). Consequently, the age divergence in stroke incidence with a less favourable trend at younger ages widened significantly during the pandemic (RTTR = 1.07, 95%CI 1[1.05,1.08], p < 0.001) and remained unchanged since (RTTR = 0.99, 95%CI [0.97,1.00], p = 0.11). Prevalence of modifiable stroke risk factors remained largely unchanged during and after the pandemic for both age groups. However, there was a significant increase in the frequency of undiagnosed premorbid hypertension and diabetes at age < 55 years during the pandemic (hypertension RR = 1.07, 95%CI [1.02-1.13]; diabetes RR = 1.22, 95%CI [1.08-1.37]). Again, this trend was most prominent for ethnic minority groups and has not improved after the pandemic. A key limitation was the use of routinely collected data, which lacked granularity to explore potential mechanisms. There was an increase in stroke incidence at younger ages, with no increase at older ages, especially for ethnic minority groups, during and after the COVID-19 pandemic. This coincided with worsening in risk factor identification and diagnosis in primary care, highlighting missed opportunities that need to be urgently addressed.