OBJECTIVES: To describe the systolic and diastolic blood pressure criteria used by community physicians to: 1) establish a diagnosis of hypertension; and 2) increase dosage or change drug therapy in treated hypertensives. METHODS: A multiethnic population sample of adults at or above 40 years old was surveyed, by random digit phone dialing in a major metropolitan area, regarding blood pressure measurement and hypertension awareness and treatment status. Respondents with and without known hypertension were asked to: 1) identify their health care providers; and 2) agree to sign and return a release form allowing the investigators to obtain copies of their medical records. Medical records received were abstracted in a standardized format. RESULTS: Medical records were obtained for 169 patients who collectively had 940 visits with 175 different providers during a consecutive 2-year period. Overall, 25% of these patients had 24-month average blood pressures of at or above 140/90 mm Hg without a diagnosis of hypertension being recorded by a physician. Over two-thirds of the undiagnosed had systolic blood pressure of 140-159 mm Hg, with diastolic pressure of less than 90 mm Hg. In persons on antihypertensive drugs (n equals 81), the average blood pressure was 147/86 mm Hg, and only 24% met the Joint National Committee-VI blood pressure goal of less than 140/90 mm Hg. A visit-level analysis indicated that when diastolic blood pressure was greater than 90 mm Hg, physicians intensified drug therapy 24% of the time, but intensification actions occurred in only 4% of visits when systolic pressure was less than 140 mm Hg and diastolic pressure was less than 90 mm Hg. Kaplan-Meier survival curves and multiple logistic regression modeling demonstrated that almost no action would be taken for persistently elevated systolic blood pressure over 20 consecutive visits. CONCLUSIONS: Community physicians do not give equal weight to systolic blood pressure of greater than 140 mm Hg as to diastolic pressure of greater than 90 mm Hg in diagnosing hypertension and intensifying treatment. This is a major determinant of the current level of unawareness of hypertension and uncontrolled, known hypertension found in national surveys. (c)2000 by Le Jacq Communications, Inc.