DOI: 10.5061/dryad.cfxpnvx46
title: Data from: Nationwide trends in incidence and mortality of stroke among younger and older adults in Denmark

description: Objective: To investigate the extent to which the incidence and mortality
 of a first-time stroke among younger and older adults changed from 2005 to
 2018 in Denmark using nationwide registries. Methods: We used the Danish
 Stroke Registry and the Danish National Patient Registry to identify
 patients aged 18–49 years (younger adults) and those aged 50+ years (older
 adults) with a first-time ischemic stroke, intracerebral hemorrhage, or
 subarachnoid hemorrhage. We computed age-standardized incidence rates and
 30-day and one-year mortality risks separately for younger and older
 adults and according to smaller age groups, stroke subtype, sex, and
 severity (Scandinavian Stroke Scale). Average annual percentage changes
 (AAPC) were computed to assess temporal trends. Results: We identified
 8,680 younger adults and 105,240 older adults with an ischemic stroke or
 intracerebral hemorrhage. The incidence rate per 100,000 person-years of
 ischemic stroke (20.8 in 2005 and 21.9 in 2018, AAPC: -0.6 [95% CI: -1.5
 to 0.3]) and intracerebral hemorrhage (2.2 in 2005 and 2.5 in 2018, AAPC:
 0.6 [95% CI: -1.0 to 2.3]) remained steady in younger adults. In older
 adults, rates of ischemic stroke and intracerebral hemorrhage declined,
 particularly in those aged 70 or older. Rates of subarachnoid hemorrhage
 declined, but more so in younger than older adults. Stroke mortality
 declined over time in both age groups, largely attributable to declines in
 the mortality after severe strokes. Most trends were similar for men and
 women. Conclusion: Incidence of ischemic stroke and intracerebral
 hemorrhage was steady in younger adults from 2005 to 2018, while it
 dropped in adults older than 70 years. Stroke mortality declined during
 this time.
description: <b>eTable 1. </b>Description of the data sources used
 in this study. <b>eTable 2.
 </b><i>International Classification of Diseases</i>
 (ICD) and <i>Anatomical Therapeutic Chemical Classification System
 </i>(ATC) codes used in the study.
 <b>eTable 3</b>. Characteristics (N, %) of patients
 with a first-time subarachnoid hemorrhage, Denmark, 2005–2018.
 <b>eTable 4. </b>Number of Joinpoints and
 corresponding Joinpoints segments, annual percent change (APC), and
 average annual percent change (AAPC) for age- and sex-specific incidence
 rates of ischemic stroke, intracerebral hemorrhage, and subarachnoid
 hemorrhage, 2005–2018. <b>eTable 5.
 </b>Number of Joinpoints and corresponding Joinpoints segments,
 annual percent change (APC), and average annual percent change (AAPC) for
 age-, severity-, and etiology-specific incidence rates of ischemic stroke
 and intracerebral hemorrhage, 2005–2018.
 <b>eTable 6. </b>Number of Joinpoints and
 corresponding Joinpoints segments, annual percent change (APC), and
 average annual percent change (AAPC) for age- and sex-specific 30-day and
 1-year mortality risks of ischemic stroke, intracerebral hemorrhage, and
 subarachnoid hemorrhage, 2005–2018. <b>eTable 7.
 </b>Number of Joinpoints and corresponding Joinpoints segments,
 annual percent change (APC), and average annual percent change (AAPC) for
 age- and severity-specific 30-day and 1-year mortality risks of ischemic
 stroke and intracerebral hemorrhage, 2005–2018.
 <b>eFigure 1. </b>Age-standardized incidence rates
 with corresponding 95% confidence intervals of a first-time ischemic
 stroke or unspecified stroke (specific codes) in younger and older adults,
 2005–2018. Fitted smoothed lines are Loess smoothers. Notice varying
 y-axes. <b>eFigure 2. </b>Age- and
 etiology-specific incidence rates with corresponding 95% confidence
 intervals of a first-time ischemic stroke (atrial fibrillation associated,
 rare risk factor associated, others) or intracerebral hemorrhage
 (hypertension associated, anticoagulation associated, others) in younger
 and older adults, 2005–2018. Atrial fibrillation diagnoses identified
 during hospitalization or within the following 180 days. Fitted smoothed
 lines are Loess smoothers. Notice varying y-axes.
 <b>eFigure 3. </b>Age-specific 1-year mortality risks
 and corresponding 95% confidence intervals following a first-time ischemic
 stroke or intracerebral hemorrhage in younger and older adults, 2005–2018.
 Fitted smoothed lines are Loess smoothers. Notice varying
 y-axes. <b>eFigure 4. </b>Age- and
 sex-specific 30-day mortality risks and corresponding 95% confidence
 intervals following a first-time ischemic stroke or intracerebral
 hemorrhage in younger and older adults. Dotted lines represent women;
 solid lines represent men), 2005–2018. Fitted smoothed lines are Loess
 smoothers. Notice varying y-axes. <b>eFigure 5.
 </b>Age-standardized and severity-specific 30-day mortality risks
 and corresponding 95% confidence intervals of a first-time ischemic stroke
 or intracerebral hemorrhage in younger and older adults, 2005–2018. Fitted
 smoothed lines are Loess smoothers. Notice varying y-axes.
 <b>eFigure 6. </b>Age-standardized and
 severity-specific 1-year mortality risks and corresponding 95% confidence
 intervals of a first-time ischemic stroke or intracerebral hemorrhage in
 younger and older adults, 2005–2018. Fitted smoothed lines are Loess
 smoothers. Notice varying y-axes. <b>eFigure 7.
 </b>Age-specific 30-day mortality risks and corresponding 95%
 confidence intervals following a first-time subarachnoid hemorrhage in
 younger and older adults, 2005–2018. Fitted smoothed lines are Loess
 smoothers. Notice varying y-axes. <b>eFigure 8.
 </b>Age-specific 1-year mortality risks and corresponding 95%
 confidence intervals following a first-time subarachnoid hemorrhage in
 younger and older adults, 2005–2018. Fitted smoothed lines are Loess
 smoothers. Notice varying y-axes.