From the Guidelines
Stroke is a significant global health concern, with ischemic strokes accounting for approximately 87% of all cases while hemorrhagic strokes make up the remaining 13%. The worldwide annual incidence of stroke is about 15 million people, with 5 million resulting in death and another 5 million leading to permanent disability 1. In the United States specifically, about 795,000 people experience a stroke each year, with 610,000 being first-time events and 185,000 being recurrent strokes 1.
Incidence and Prevalence
The prevalence of stroke increases dramatically with age, doubling for each decade after age 55. Ischemic strokes, caused by blood clots or other blockages in brain arteries, have an incidence rate of approximately 130-140 per 100,000 person-years in Western countries. Hemorrhagic strokes, which include intracerebral hemorrhage and subarachnoid hemorrhage, have a lower incidence of about 20-30 per 100,000 person-years 1.
Risk Factors
Risk factors for both types include:
- Hypertension
- Smoking
- Diabetes
- High cholesterol though hemorrhagic strokes are particularly associated with uncontrolled hypertension and anticoagulant use 1.
Global Prevalence
The global prevalence of stroke survivors is estimated at 33 million, with higher rates in developed countries due to better survival rates despite treatment 1. Understanding these epidemiological patterns is crucial for healthcare planning and preventive strategies.
From the Research
Incidence and Prevalence of Ischemic and Hemorrhagic Stroke
- The incidence of ischemic stroke is higher than that of hemorrhagic stroke, with approximately 73% to 86% of strokes being ischemic and 8% to 18% being hemorrhagic 2.
- However, a study found that 41.9% of strokes were hemorrhagic and 58.1% were ischemic, which may be due to improved CT scan availability or an increase in therapeutic use of antiplatelet agents and warfarin 2.
- Arterial hypertension is a major risk factor for both ischemic and hemorrhagic strokes, and approximately 30% of ischemic strokes occur after a previous stroke or transient ischemic attack 3.
Risk Factors and Mortality
- Factors that favor ischemic strokes over hemorrhagic strokes include diabetes, atrial fibrillation, previous myocardial infarction, previous stroke, and intermittent arterial claudication 4.
- Smoking and alcohol consumption are more commonly associated with hemorrhagic strokes, while age, sex, and hypertension do not predict stroke type 4.
- Hemorrhagic strokes are associated with a higher mortality risk, particularly in the first 3 months after stroke, with an initial 4-fold increased risk that decreases to 1.5-fold after 3 weeks 4.
Treatment and Prevention
- The use of blood pressure-lowering drugs, such as angiotensin-converting enzyme inhibitors, can reduce the risk of primary stroke by 38% 5.
- Combination therapy with antiplatelets, ACE inhibitors, and statins may have additive protective effects in reducing ischemic stroke severity and tissue at risk 6.
- Guidelines for secondary prevention of ischemic stroke support the use of blood pressure-lowering drugs, which can reduce the risk of subsequent stroke by 1.9% 3.