Hypertension screening in general practice. Report on behalf of the General Practitioner Hypertension Study Group.

In 1974 eight general practitioners decided to co-operate in a hypertension screening exercise in their practices. The reasons for the survey and the methodology are described and the results of screening over 28,000 patients are given. The cut-off point for normal diastolic blood pressure was 89 mmHg and 23,979 (85 per cent) patients were considered to be normosensitive on this criterion, 694 (2.5 per cent) patients were already known by their doctors to have hypertension; 991 (3.5 per cent) had an initial abnormal reading but subsequent readings were normal. The survey identified 2,018 patients (7.12 per cent) as being hypertensive and 575 (2 per cent) failed to complete the survey. Because of the ever-changing population in the practices, 100 per cent surveillance was not achieved. It is considered necessary to carry out continuous case finding for the presence of hypertensive patients in general practice.