Executive Summary of Stroke Statistics in Korea 2018: A Report from the Epidemiology Research Council of the Korean Stroke Society

Abstract

Despite the great socioeconomic burden of stroke, there have been few reports of stroke statistics in Korea. In this scenario, the Epidemiologic Research Council of the Korean Stroke Society launched the "Stroke Statistics in Korea" project, aimed at writing a contemporary, comprehensive, and representative report on stroke epidemiology in Korea. This report contains general statistics of stroke, prevalence of behavioral and vascular risk factors, stroke characteristics, pre-hospital system of care, hospital management, quality of stroke care, and outcomes. In this report, we analyzed the most up-to-date and nationally representative databases, rather than performing a systematic review of existing evidence. In summary, one in 40 adults are patients with stroke and 232 subjects per 100,000 experience a stroke event every year. Among the 100 patients with stroke in 2014, 76 had ischemic stroke, 15 had intracerebral hemorrhage, and nine had subarachnoid hemorrhage. Stroke mortality is gradually declining, but it remains as high as 30 deaths per 100,000 individuals, with regional disparities. As for stroke risk factors, the prevalence of smoking is decreasing in men but not in women, and the prevalence of alcohol drinking is increasing in women but not in men. Population-attributable risk factors vary with age. Smoking plays a role in young-aged individuals, hypertension and diabetes in middle-aged individuals, and atrial fibrillation in the elderly. About four out of 10 hospitalized patients with stroke are visiting an emergency room within 3 hours of symptom onset, and only half use an ambulance. Regarding acute management, the proportion of patients with ischemic stroke receiving intravenous thrombolysis and endovascular treatment was 10.7% and 3.6%, respectively. Decompressive surgery was performed in 1.4% of patients with ischemic stroke and in 28.1% of those with intracerebral hemorrhage. The cumulative incidence of bleeding and fracture at 1 year after stroke was 8.9% and 4.7%, respectively. The direct costs of stroke were about ₩1.68 trillion (KRW), of which ₩1.11 trillion were for ischemic stroke and ₩540 billion for hemorrhagic stroke. The great burden of stroke in Korea can be reduced through more concentrated efforts to control major attributable risk factors for age and sex, reorganize emergency medical service systems to give patients with stroke more opportunities for reperfusion therapy, disseminate stroke unit care, and reduce regional disparities. We hope that this report can contribute to achieving these tasks.

Keywords: Epidemiology; Statistics; Stroke.

Figure 1.

Age- and sex-standardized incidence rates of first-ever stroke by stroke type. Standardized rate denotes the number of patients per 100,000 population. Standardization was made based on the 2005 Population and Housing Census of Korea. Stroke incidence was evaluated using the National Health Insurance Service–National Sample Cohort (NHIS-NSC) database from 2002 to 2013.

Figure 2.

Secular trends of age-standardized prevalence (age ≥50 years) of stroke. Standardization was made based on the 2005 Population and Housing Census of Korea. Stroke prevalence was obtained using the Korea National Health and Nutrition Examination Survey (KNHANES) database from 1998 to 2014.

Figure 3.

Secular trends of age-standardized stroke mortality by stroke type. Standardized mortality denotes the number of deaths per 100,000 population. Standardization was made based on the 2005 Population and Housing Census of Korea. Stroke mortality was estimated using Annual Reports on the Cause of Death and Population and Housing Census of Korea from 2006 to 2015.

Figure 4.

Age-standardized stroke mortality by region. Standardized mortality denotes the number of deaths per 100,000 population. Standardization was made based on the 2005 Population and Housing Census of Korea. Stroke mortality was estimated using Annual Reports on the Cause of Death and Population and Housing Census of Korea from 2006 to 2015.

Figure 5.

Age-standardized prevalence of hypertension in the general population by region. Standardization was made based on the 2005 Population and Housing Census of Korea. Prevalence of hypertension was obtained using the Korea National Health and Nutrition Examination Survey (KNHANES) database from 2010 to 2014.

Figure 6.

Prevalence of (A) current cigarette smoking^* and (B) high-risk alcohol intake^† in the general population (adults aged ≥19 years) by sex. ^*Current smoking was defined as a current smoker with a lifetime history of smoking ≥5 packs (100 cigarettes). ^†High-risk alcohol intake was defined as drinking with average alcohol consumption above 7 glasses in men (5 glasses in women) and twice or more a week. ^{*, †}These two footnotes: standardization was made based on the 2005 Population and Housing Census of Korea. Prevalence of smoking and alcohol drinking was estimated using the Korea National Health and Nutrition Examination Survey (KNHANES) database from 1998 to 2014.

Figure 7.

Age-standardized prevalence^* of obesity^† in the stroke population (adults aged ≥19 years). ^*Standardization was made based on the 2005 Population and Housing Census of Korea. Prevalence of obesity was estimated using the Korea National Health and Nutrition Examination Survey (KNHANES) database from 2008 to 2014. ^†Obesity was defined as a body mass index (BMI) >30 according to the World Health Organization classification. BMI was calculated as weight in kilograms divided by height in square meters.

Figure 8.

Prevalence of atrial fibrillation in patients with acute ischemic stroke. Calculated using the Clinical Research Collaboration for Stroke in Korea (CRCS-K) database from January 2010 to March 2015 in all age groups.

Figure 9.

Stroke type in Korea. Obtained from the 5th (2013) and 6th (2014) Acute Stroke Quality Assessment Program (ASQAP) database. SAH, subarachnoid hemorrhage; ICH, intracerebral hemorrhage.

Figure 10.

Secular trends in ischemic stroke subtypes. Ischemic stroke subtype was evaluated using the Clinical Research Collaboration for Stroke in Korea (CRCS-K) database from April 2008 to March 2015. The magnetic resonance imaging-based diagnostic algorithm for acute ischemic stroke subtype classification (MAGIC) [37] was applied to all patients with stroke hospitalized since July 2011.

Figure 11.

Stroke severity at admission in (A) acute ischemic^* and (B) hemorrhagic stroke.^† NIHSS, National Institutes of Health Stroke Scale; GCS, Glasgow Coma Scale. ^*Stroke Severity data (NIHSS scores) in patients with acute ischemic stroke were obtained from the Clinical Research Collaboration for Stroke in Korea (CRCS-K) database from April 2008 to March 2015; ^†Stroke Severity data (GCS scores) in patients with acute hemorrhagic stroke were obtained from the 5th (2013) and 6th (2014) Acute Stroke Quality Assessment Program (ASQAP) database.

Figure 12.

Secular trends of (A) onset-to-arrival time and (B) proportions of patients with stroke arriving within 3 hours from onset. Time to arrival and proportions of patients with stroke by arrival time were obtained from the Acute Stroke Quality Assessment Program (ASQAP) database from 2nd (2008) to 6th (2014).

Figure 13.

Ambulance utilization rates among patients with stroke by region. Ambulance utilization rates were obtained from the 5th (2013) and 6th (2014) Acute Stroke Quality Assessment Program (ASQAP) database.

Figure 14.

Intravenous thrombolysis (IVT) rates by region. IVT rates were calculated using the 5th (2013) and 6th (2014) Acute Stroke Quality Assessment Program (ASQAP) database.

Figure 15.

Secular trends in proportions of hospitals with stroke unit care. Information on hospitals providing stroke unit care was obtained from the Acute Stroke Quality Assessment Program (ASQAP) database from 2nd (2008) to 6th (2014).

Figure 16.

Distribution of hospitals with stroke units certified by the Korean Stroke Society in 2016.

Figure 17.

Antiplatelet and anticoagulant prescription for ischemic stroke or transient ischemic attack at admission and discharge. Data on antiplatelet and anticoagulant prescription were obtained from the Clinical Research Collaboration for Stroke in Korea (CRCS-K) database from April 2008 to March 2015. NOAC, non-vitamin K antagonist oral anticoagulants. (A) Antiplatelets at admission. (B) Antiplatelets at discharge. (C) Anticoagulants at admission. (D) Anticoagulants at discharge.

Figure 18.

Direct costs (KRW) of stroke under the coverage of the National Health Insurance Services (NHIS) in Korea. Direct costs of stroke were obtained using the NHIS big data database from 2011 to 2015. 1 USD was approximately 1,200 won (KRW) on May 1, 2018.