Trends in Stroke Incidence in High-Income Countries in the 21st Century: Population-Based Study and Systematic Review

Abstract

Background and Purpose- Population-based studies provide the most reliable data on stroke incidence. A previous systematic review of population-based studies suggested that stroke incidence in high-income countries decreased by 42% between the 1970s and early 2000s. However, it is uncertain whether this trend of steady decline has been maintained in more recent periods. Methods- Data from OCSP (Oxfordshire Community Stroke Project; 1981-1986) and OXVASC (Oxford Vascular Study; 2002-2017) along with other published population-based stroke incidence studies that reported temporal trends of stroke incidence since 1990 in high-income countries were included. Age-standardized relative incidence rate ratios were calculated for each study and then pooled with inverse-variance weighted random-effects meta-analysis. Projection estimates were calculated for the number of incident stroke patients in the United Kingdom from year 2015 to 2045. Results- In Oxfordshire, stroke incidence fell by 32% from OCSP to OXVASC, with a similar trend before or after year 2000. With the projected aging population, if the age-specific stroke incidence continued to decrease at its current rate (6% every 5 years), there would still be a 13% increase of the number of first-ever strokes in the United Kingdom up to year 2045. Incorporating the Oxfordshire data with other 12 population-based studies, stroke incidence declined steadily between the 1990s and 2010s within each study, resulting in a 28% decline over an average period of 16.5 years (pooled incidence rate ratio, 0.72 [95% CI, 0.66-0.79]; P<0.0001). The trend was the same for men (0.69 [95% CI, 0.61-0.77]; P<0.0001) and women (0.66 [95% CI, 0.59-0.74]; P<0.0001) and remained consistent after year 2010 in OXVASC. Proportion of disabling or fatal stroke also decreased over time (early versus later period, 53.6% versus 46.1%; P=0.02). Conclusions- Stroke incidence is continuing to decline with steady rate in Oxfordshire and in other high-income settings. However, the absolute number of strokes occurring is not falling.

Keywords: cohort study; incidence; stroke; systematic review.

Figure 1.

Temporal trends of standardized stroke incidence in population-based studies reporting at least 1 time point after year 2010 (1990–2010).

Figure 2.

Meta-analysis (random effects) of standardized incidence rate ratio (IRR; temporal trend) in population-based studies of first-ever stroke (1990–2010). †Raw numbers of incident stroke cases for each study for the 2 time periods included are presented in Table 1.

Figure 3.

Meta-analysis (random effects) of standardized incidence rate ratio (IRR; temporal trend) in population-based studies of first-ever stroke stratified by stroke severity. A, Change of the proportions of disabling or fatal stroke. B, Change of IRR. OR indicates odds ratio. †Raw numbers of incident stroke cases for each study for the 2 time periods included can be derived from A.