Prevalence of masked uncontrolled hypertension according to the number of office blood pressure measurements

Abstract

Introduction and objectivesThe reported prevalence of masked uncontrolled hypertension (MUCH) varies because many studies are not comparable as they use different measurement methodologies. To evaluate the influence of the number of office blood pressure readings on the prevalence of MUCH we conducted a cross-sectional, multicenter study in treated hypertensive patients. Patients and methodsWe carried out an observational, cross-sectional, multicenter study in 33 Spanish hospital-based hypertension units, involving 35 investigators and 12 Autonomous Communities. Six blood pressure readings and a 24-h ambulatory blood pressure monitoring were performed in treated hypertensive patients. The means of the first 3 readings (P123), the 2nd, 3rd and 4th readings (P234), the 3rd, 4th and 5th readings (P345) and the last 3 readings (P456) were compared with mean 24-h blood pressure. MUCH was defined as office blood pressure <140/90mmHg and 24-h blood pressure ≥130/80mmHg, considering the first 3 readings (MUCH123), the 2nd, 3rd and 4th readings (MUCH234), the 3rd, 4th and 5th readings (MUCH345) and the last 3 readings (MUCH456). ResultsWe included 498 hypertensive patients. Mean (standard deviation) office blood pressure measurements were: (P123) 141(18)/82(11); (P234) 139(17)/81(11); (P345) 138(17)/81(11) and (P456) 137(16)/80(10) mmHg. Mean 24-h blood pressure was 127(13.8)/75(9.5) mmHg. The correlation coefficients between ambulatory and office systolic/diastolic blood pressure were (P123):0.48/0.50; (P234):0.50/0.52; (P345):0.50/0.54; and (P456):0.50/0.55 (p<0.001, all). The prevalences of MUCH123, MUCH234, MUCH345 and MUCH456 were 14.5%, 18.9%, 19.5% and 21.1%, respectively. ConclusionsThe prevalence of MUCH diagnosis depends on the serial office blood pressure readings, being much higher for the last three blood pressure readings. Discarding the first and second office blood pressure measures seems to be the most accurate method for diagnosing MUCH.