Self-reported hypertension treatment practices among primary care physicians: blood pressure thresholds, drug choices, and the role of guidelines and evidence-based medicine.

BACKGROUND: Primary care physician treatment practices affect the rate of hypertension control to the goal of 140/90 mm Hg. Awareness of and agreement with national hypertension management guidelines, and grounding in evidence-based medicine principles, may be important determinants of practice.
METHODS: A 26-item mail questionnaire was sent to a national sample of 1200 primary care physicians. The questionnaire elicited (1) the blood pressure (BP) criteria physicians use to initiate and intensify hypertension treatment, (2) first-line drug treatment choices, (3) familiarity with the Joint National Committee on Detection, Evaluation, and Treatment of High Blood Pressure (JNC) hypertension treatment guidelines, and (4) familiarity with research methods used to develop evidence-based medicine guidelines. The analysis focused on (1) determining the percentage of physicians who reported treatment practices consistent with JNC recommendations and (2) the relation between familiarity with JNC guidelines, evidence-based medicine methods, and reported treatment practices.
RESULTS: The overall response rate was 34%, with no important differences in demographic or professional training variables between respondents and nonrespondents. For middle-aged patients with uncomplicated hypertension, 33% of physicians would not start drug therapy unless the diastolic BP was greater than 95 mm Hg, and 43% would not start unless the systolic BP was greater than 160 mm Hg. In patients without complications who were receiving drug treatment, 25% of physicians would not intensify therapy for a persistent diastolic BP of 94 mm Hg, and 33% would not intensify therapy for a systolic BP of 158 mm Hg. Physicians were generally less aggressive in older patients. Angiotensin-converting enzyme inhibitors were the most common first-line drug choice. Forty-one percent of physicians had not heard of or were not familiar with the JNC guidelines. In multiple logistic regression models, familiarity with the JNC guidelines was associated with lower treatment thresholds, and increased familiarity with research methods was associated with greater use of diuretics or beta-blockers as first-line agents.
CONCLUSIONS: Many physicians have higher BP thresholds for the diagnosis and treatment of hypertension than the 140/90 mm Hg criterion recommended by the JNC. Therefore, further improvements in population hypertension control will require physician behavior change. Physician practice is associated with awareness of practice guidelines and familiarity with evidence-based medicine methods, but the precise nature and extent of this relation requires further study.