C038: Categorization of blood pressure by conventional versus ambulatory blood pressure measurement

• Published in: American journal of hypertension 2000-04, Vol.13 (S2), p.223A-223A
• Main Authors: Schwartz, G.L., Meissner, I., Whisnant, J.P., Sheps, S.G., O'Fallon, W.M., Covalt, J.L., Sicks, J.D., Baily, K.R., Wiebers, D.O.
• Format: Article
• Language: English
• Subjects: ambulatory blood pressure; Measurement
• ISSN: 0895-7061; 1941-7225; 1879-1905
• DOI: 10.1016/S0895-7061(00)00758-5

We categorized blood pressure (BP) status (normotension [NTN] or hypertension [HTN]) in a population-based sample of 495 adults ≥45 years old by home, and office measurements of BP (conventional), and by 24-hour ambulatory BP monitoring (ABPM). Categorization using conventional measures of BP was determined by the average of two random-zero measurements obtained at home plus four measures obtained in the office. HTN was defined as systolic (S) BP ≥ 140 mm Hg or diastolic (D) BP ≥ 90 mm Hg (JNC VI criteria). Categorization using ABPM was determined by the average of readings measured every 10 minutes during the awake period (AP), and separately on the average of readings measured every 10 minutes during the asleep period (SP) (JNC VI criteria). HTN during the AP was defined as average SBP ≥ 135 mm Hg or average DBP ≥ 85 mm Hg. HTN during the SP was defined as average SBP ≥ 120 mm Hg or average DBP ≥ 75 mm Hg. Of 209 subjects categorized as HTN by conventional measurement, 30 (14%) were categorized as NTN by average AP BP. Of 286 subjects categorized as NTN by conventional measurement, 71 (25%) were categorized as HTN by average AP BP and 70 (24%) were categorized as HTN by average SP BP. Of 245 subjects classified as NTN by average AP BP, 47 (19%) were categorized as HTN by average SP BP. Compared to conventional measurement, ABPM identifies more individuals at risk from elevated BP. Conventional BP is associated with high rates of both white coat NTN (24%) and white coat HTN (14%). These observations argue for more routine use of 24-hour ABPM to determine individual risk from elevated BP.