Antihypertensive Treatment Based on Blood Pressure Measurement at Home or in the Physician’s Office - A Randomized Controlled Trial
Jan A. Staessen, MD, PhD, Elly Den Hond, PhD, Hilde Celis, MD, Robert Fagard, MD, PhD, Louis Keary, MD, Guy Vandenhoven, MD, Eoin T. O’Brien, MD, FRCP, for the Treatment of Hypertension, Based on Home or Office Blood, Pressure (THOP) Trial Investigators
Context. Self-measurement of blood pressure is increasingly used in clinical practice, but how it affects the treatment of hypertension requires further study.
Objective. To compare use of blood pressure (BP) measurements taken in physicians’ offices and at home in the treatment of patients with hypertension.
Design, Setting, and Participants. Blinded randomized controlled trial conducted from March 1997 to April 2002 at 56 primary care practices and 3 hospitalbased outpatient clinics in Belgium and 1 specialized hypertension clinic in Dublin, Ireland. Four hundred participants with a diastolic BP (DBP) of 95 mm Hg or more as measured at physicians’ offices were enrolled and followed up for 1 year.
Interventions. Antihypertensive drug treatment was adjusted in a stepwise fashion based on either the self-measured DBP at home (average of 6 measurements per day during 1 week; n=203) or the average of 3 sitting DBP readings at the physician’s office (n=197). If the DBP guiding treatment was above (>89 mm Hg), at (80-89 mm Hg), or below (<80 mm Hg) target, a physician blinded to randomization intensified antihypertensive treatment, left it unchanged, or reduced it, respectively.
Mean Outcome Measures. Office and home BP levels, 24-hour ambulatory BP, intensity of drug treatment, electrocardiographic and echocardiographic left ventricular mass, symptoms reported by questionnaire, and costs of treatment.
Results. At the end of the study (median follow-up, 350 days; interquartile range, 326-409 days), more home BP than office BP patients had stopped antihypertensive drug treatment (25.6% vs 11.3%; P<.001) with no significant difference in the proportions of patients progressing to multiple-drug treatment (38.7% vs 45.1%; P=.14). The final office, home, and 24-hour ambulatory BP measurements were higher (P<.001) in the home BP group than in the office BP group. The mean baseline-adjusted systolic/diastolic differences between the home and office BP groups averaged 6.8/3.5 mm Hg, 4.9/2.9 mm Hg, and 4.9/2.9mmHg, respectively. Left ventricular mass and reported symptoms were similar in the 2 groups. Costs per 100 patients followed up for 1 month were only slightly lower in the home BP group (€3875 vs €3522 [$4921 vs $4473]; P=.04).
Conclusions. Adjustment of antihypertensive treatment based on home BP instead of office BP led to less intensive drug treatment and marginally lower costs but also to less BP control, with no differences in general well-being or left ventricular mass. Selfmeasurement allowed identification of patients with white-coat hypertension. Our findings support a stepwise strategy for the evaluation of BP in which self-measurement and ambulatory monitoring are complementary to conventional office measurement and highlight the need for prospective outcome studies to establish the normal range of home-measured BP.