Changing trends in hypertension detection and control: the Chicago experience.

Of 177,692 persons screened in 1977 as part of an ongoing City-Wide Hypertension Screening Program in Chicago, 14,988 (8.4%) had diastolic blood pressure (BP) greater than or equal to 95 mm Hg as compared to 13.2% of a similar population in 1976. Only 7% (3,910) of the hypertensive population (diastolic BP greater than or equal to 95 mm Hg or presently on antipressor drugs) had previously undetected hypertension in contrast to 11.9% (4,184) the year before and 48.7% in the same community in 1972. Conversely, 73.2% (40,738) had adequately controlled blood pressure as contrasted to 59.3% (20,897) the previous year and 20.6% in 1972. Of the remaining hypertensives, 7.5% (4,201) were known but not treated and 12.3% (6,824) were under treatment but not controlled in contrast to 12.1% (4,251) and 16.8% (5,905) respectively the year before. This upward trend in controlled hypertension was present in all strata of the population.

Evaluation of an automated blood pressure measuring device intended for general public use.

Responding to Chicago newspaper reports, measurements of blood pressure by a publicly available, automated coin-operated device were compared with those of human observers using the standard cuff and auscultatory technique. One machine was examined in the laboratory, and eight others at randomly selected sites. Analysis of readings made on 100 persons in the laboratory and 227 in the field led to the following conclusions: 1) On the average, the machines measured fifth phase diastolic blood pressure at nearly the same level as did human observers; 2) The machines were more variable measuring systolic blood pressure with four differing from the average human reading by 1mm Hg or less, but two differing by 8mm Hg or more; 3) The agreement between machine-human pairs of readings was not as good as between human-human pairs, but the differences in level of agreement--both in determining the actual value and in categorizing the values as normal, borderline, or high--were small and have little practical importance; 4) Linear regression analyses of the relationship between simultaneously determined machine and human readings indicated that the average human-machine difference was the same over the range of pressures tested. Publicly available blood pressure measuring devices should be labeled concerning their purposes, capabilities, and limitations. Rules and regulations governing their use in the City of Chicago are being prepared by this city's Legal Department.