Population-Based Survey Evaluates Stroke in China

January 11, 2017—A study reporting on the prevalence, incidence, and mortality of stroke in China was published online ahead of print in Circulation by Wenzhi Wang, MD, et al. The investigators concluded that the stroke burden in China has increased over the last 30 years and remains particularly high in rural areas; furthermore, there is a north-to-south gradient, with the greatest stroke burden observed in the northern and central regions.

According to the investigators, China bears the biggest stroke burden in the world. However, little is known about the current prevalence, incidence, and mortality of stroke at the national level and the trends over the last 30 years.

As summarized in Circulation, a nationally representative door-to-door survey was conducted in 2013. The survey was conducted in 155 urban and rural centers in 31 provinces in China and included of 480,687 adults who were 20 years of age or older. All stroke survivors were considered as prevalent stroke cases at the prevalent time (August 31, 2013). First-ever strokes that occurred during 1 year preceding the survey point–prevalent time were considered as incident cases.

Using CT, MRI, and autopsy findings, strokes were categorized into ischemic stroke, intracerebral hemorrhage, subarachnoid hemorrhage, and stroke of undetermined type. 

Of 480,687 participants, 7,672 were diagnosed with a prevalent stroke (1596 per 100,000 people) and 1,643 had incident strokes (345.1 per 100,000 person-years). The age-standardized prevalence rate was 1,114.8 per 100,000 people. The incidence and mortality rates were 246.8 and 114.8 per 100,000 person-years, respectively. Pathological type of stroke was documented by CT/MRI brain scanning in 90% of prevalent and 83% of incident stroke cases. 

The investigators found that ischemic stroke constituted 69.6% and 77.8%, intracerebral hemorrhage 23.8% and 15.8%, subarachnoid hemorrhage 4.4% and 4.4%, and undetermined type 2.1% and 2%, among incident and prevalent strokes, respectively. 

Age-specific stroke prevalence in men who were 40 years of age or older was significantly greater than those in women (P < .001). The most prevalent risk factors among stroke survivors were hypertension (88%), smoking (48%), and alcohol use (44%). 

Stroke prevalence estimates in 2013 were statistically greater than those reported in China 3 decades ago, especially among rural residents (P = .017). The highest annual incidence of and mortality due to stroke was in the Northeast areas of China (365 and 159 per 100,000 person-years), then Central areas (326 and 154 per 100,000 person-years). The lowest incidence was in Southwest area of China (154 per 100,000 person-years), and the lowest mortality was in South China (65 per 100,000 person-years) (P < .002), reported the investigators in Circulation.