Hemorrhagic Stroke

Risk factors for stroke that cannot be controlled include increasing age, gender (males have higher risk), family history, prior stroke, and race. Risk factors that can be controlled with the appropriate lifestyle modifications include hypertension, diabetes mellitus, high cholesterol, alcohol use, and cigarette smoking.

Figure 1 illustrates the degree of increase in a person’s risk for stroke, depending on the particular risk factor. Persons over age 65 are 2 times more likely to have a stroke than those under 65. Those over 75 have 4 times the risk, and those over 85 are 8 times more likely to experience a stroke. Diabetes increases your risk of stroke 3 times, males are 1.5 times more likely to have a stroke compared to females, having a previous stroke increases your risk by 10 times, and smoking increases your risk of stroke 2 times.

Figure 1: Risk Factors for Stroke

Source: National Stroke Association, Stroke Risk Factors and Their Impact

The Hypertension Factor

Hypertension (HTN), or high blood pressure, is a more important risk factor in hemorrhagic stroke (intracerebral hemorrhage, ICH) than it is in ischemic stroke. Hypertension has been consistently shown to increase the risk of ICH. Some studies have shown that hypertension is the main cause of ICH in over 85% of the cases.(1) In Australia, a hospital-based case-control study found that hypertension more than doubled the risk of ICH. Figure 2 demonstrate the various risks of those with hypertension-associated hemorrhagic stroke in this study.(2) Important to note is that those people who were hypertensive but had stopped taking their medications were more than twice as likely to have an ICH compared to hypertensive patients who were taking their medications. Those patients who died in this study were more than 5 times as likely to have ICH due to hypertension compared to survivors.(3)

	OR	95% Confidence Interval (CI)
No HTN medications	4.98	2.25-11.02
Currently taking meds	1.95	1.20-3.16
HTN and <55 years	7.68	2.65-22.5
HTN and current smoker	6.12	2.29-16.35

Figure 2: Odds ratios for patients with hypertension-associated hemorrhagic stroke.

Race and Age Factors

Race is another important risk factor for ICH. Both African Americans and Hispanics are at increased risk of having an ICH compared to non-Hispanic whites. An observatrional study of hospital ICD codes in New Mexico found that Hispanics in New Mexico were twice as likely to have ICH compared to non-Hispanic whites (RR=2.10, p=0.001).(4) In a Texas study between 1980-1995, age and race showed an interaction effect. Between ages 45-59, African Americans and Hispanic Americans had the highest ICH mortality rates compared to whites (RR=4.0 and 1.9, respectively). Between ages 60-74, the relative risk for African Americans and Hispanics was 1.7 and 1.3, respectively. For those over 75, all three races showed similar mortality rates from ICH.(5) This study is in agreement with an observational study of hospital records in Cincinatti in 1988. This study showed that young and middle-aged blacks are more than twice as likely (RR=2.3, 95% Confidence Interval 1.5-3.6) to have ICH compared to whites of a similar age.(6) It has been hypothesized that the reasons for the racial discrepancies may include education and socioeconomic status. Hypertension, which has a higher prevalence among blacks, is one reason for the differences in mortality rates due to ICH.

The good news is that hemorrhagic stroke is highly preventable. A healthy diet and regular physical activity are two ways in which some of these factors can be controlled.(1) But most importantly, reducing hypertension would significantly reduce the amount of hemorrhagic strokes in this nation.

References

1. Kumral E, Ozkaya B, Sagduyu A, Sirin H, Vardarli E, and Pehlivan M. The Edge Stroke Registry: a hospital-based study in the Aegean region, Izmir, Turkey. Analysis of 2,000 stroke patients. [Review] Cerebrovascular Diseases. 8(5):278-88, 1998.

2. Gorelick PB, Sacco RL, Smith DB, et al. Prevention of a first stroke: a review of guidelines and a multidisciplinary consensus statement from the National Stroke Association. [Review] JAMA. 281(12):1112-20, 1999.

3. Thrift AG, McNeil JJ, Forbes A, and Donnan GA. Three important subgroups of hypertensive persons at a greater risk of intracerebral hemorrhage. Melbourne Risk Factor Study Group. Hypertension. 31(6):1223-9, 1998.

4. Bruno A, Carter S, Qualls C, and Nolte KB. Incidence of spontaneous intracerebral hemorrhage among Hispanics and non-Hispanic whites in New Mexico. Neurology. 47(2):405-8, 1996.

5. Morgenstern LB and Spears WD. A triethnic comparison of intracerebral hemorrhage mortality in Texas. Annals of Neurology. 42(6):919-23, 1997.

6. Broderick JP, Brott T, Tomsick T, Huster G, and Miller R. The risk of subarachnoid and intracerebral hemorrhages in blacks as compared with whites. New England Journal of Medicine. 326(11):733-6, 1992.

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