Kurland, Leonard T.

This study has attempted to identify all patients in the population of Rochester, Minnesota, who had stroke during the period 1955 through 1969, and to determine the course and survival of patients who have had stroke. Cerebral infarction from all causes, including embolic infarction, accounted for 79% of all strokes. Intracerebral hemorrhage accounted for 10% of the cases, and subarachnoid hemorrhage accounted for 6%. The average annual incidence rate for the 15 years of the study was 164 per 100,000 population per year. The rates for all strokes and for cerebral infarction were significantly higher for men than for women, except in the youngest age group. After the end of an earlier study, 1945 through 1954, the average annual incidence rate for all strokes decreased in each succeeding five-year interval and reached 141 during the period 1965 through 1969. The decrease in rates is apparent for all strokes and for cerebral infarction, and is more apparent for women than for men. The prevalence rate on January 1, 1960, and January 1, 1965, of about 700 per 100,000 population was higher than the rate for January 1, 1970, reflecting decreasing incidence rates. A study of the functioning capacity of survivors of stroke after six months indicates that only 4% required total care and nearly 30% were functioning normally. Fifty-four percent had some neurological deficit that may have been benefited by rehabilitative care. Aphasia was an important residual incapacity in 10%. The first-year recurrence rate of stroke was 10%, and the five-year recurrence rate was 20%. Among patients with stroke who died, 38% died of the initial stroke, 10% of a subsequent stroke, and 18% of heart disease. During the 25-year period, 1945 through 1969, there has been a trend toward gradually increasing survival for cerebral infarction in this community.

The records of the Mayo Clinic have been used as the primary basis for the study of stroke in the population of Rochester, Minnesota, from 1945 through 1954. The incidence rate for first stroke of all types was 1947/100,000/year. The rates increased with age, and at age 65 to 74 years, about 1% of the population was affected annually. No significant differences were noted between men and women. The rate for cerebral thrombosis was 146/l00,000/year for all ages. Cerebral hemorrhage represented less than 10% of all strokes and occurred in less than 15% of those who died; this is contrary to what is published in the U.S. Mortality Statistics . The prevalence rate was 547/100,000 on January 1, 1955. Twenty-one percent of these persons who had previously had a stroke were functioning with no incapacity on the date of prevalence determination and only 3% were bedridden. Death certificates were reviewed for all those who died after a stroke. Among those who died within a month after a stroke, some type of stroke was noted as the underlying or an associated cause of death in 91%. However, among those who died more than a month after a stroke, only 54% had such a diagnosis recorded. Probability of surviving after each type of stroke was determined and compared with survival in a normal population. The curve showing probability of surviving from cerebral thrombosis diverges throughout its course from that of the expected survival but diverges more sharply in the first several months. Among those patients with stroke who died, 41% died of causes related to the acute stroke and 10% died of a subsequent stroke. Heart disease was the cause of nearly twice as many deaths as was a subsequent stroke among those who survived the initial stroke. Autopsies were performed on approximately 50% of those persons who died following a stroke, and information from these studies confirmed the high degree of accuracy of the clinical appraisals.