The National Survey of Stroke. Survival and prevalence.

Based on five years of data, 1971-1976, age- and type-specific survival rates were calculated. These rates, in addition to the incidence rates reported in chapter 4, became the basis for generating estimates of prevalence. The results corroborated many of the hypotheses about stroke survival and prevalence. Briefly, the results from the National Survey of Stroke indicate the following: 1. Survival after an initial attack is a function of both age and type of stroke. Younger patients survive longer than do older patients, and infarction patients survive longer than do hemorrhagic stroke patients; 2. Regardless of type of stroke or age at first stroke, there is a period of high mortality for the first 30 days, followed by a fluctuating mortality for the next 150 days, and a constant mortality thereafter for the next four and one-half years; and 3. The prevalence of acute stroke was approximately 1.7 million, a rate of 794 per 100,000 population, as of July 1, 1976. Approximately 75 percent of the prevalence cases represent individuals between the ages of 55 and 84 years, and the age-specific rates show a marked increase with advancing age.