either two or more readings per encounter, taken at two or more encounters, with blood pressures that average over 95 mm Hg diastolic or over 160 mm Hg systolic in adult patients; or two or more readings at a single encounter with an average diastolic blood pressure of 120 mm Hg or more; plus evidence of abnormalities of the heart (enlargement, failure), kidney (albuminuria, azotemia), eye, or the brain attributed to hypertension