Essential Hypertension

Abstract

THIS follow-up study was undertaken to clarify the natural history of essential hypertension.Information of this type is in- dispensable to evaluation of therapy for this disease.Keith, Wagener, and Barker' in 1939 dem- onstrated the value of their classification of hypertensive changes in the retina as an aid to prognosis in hypertensive patients.However, the number of patients with milder forms of hypertension in that series was small and the study covered a period of less than 10 years.Consequently, we thought that a more exten- sive investigation of the prognostic value of ophthalmoscopic findings and other criteria would be desirable. Material and MethodThis study was based on 631 cases in which essential hypertension was first diagnosed at the Mayo Clinic in 1940.The follow-up period was at least 5 years in 557 cases and at least 20 years in 540.An attempt was made to obtain follow-up information for all patients with group-3 or group- 4 hypertension.However, to prevent the number of cases of group-i and group-2 hypertension from becoming unwieldy, follow-up information was sought from every patient in these categories who was seen in the first 6 months of 1940 and from only every third patient who was seen in the last 6 months of 1940.Patients with a systolic blood pressure of 160 mm.Hg or more or with a diastolic pressure of 90 mm. or more, or with both, were considered hypertensive.Only 17 patients in the entire series failed to have at least one recorded dias- tolic-blood-pressure reading of 90 mm. or more, and all these had a systolic pressure in excess of 160 mm.Of the 540 patients traced for at least From the Mayo Clinic and Mayo Foundation, Rochester, Minnesota.The Section on Biometry and Medical Statistics, Mayo Clinic, gave helpful advice and provided the statistics that appear in this paper.