Clinical evaluation of 24 h ambulatory monitoring of blood pressure under various environmental conditions (home and work versus hospital).

: OBJECTIVE: To assess the effects of activity and environment on the spontaneous changes in 24 h blood pressure monitoring (BPM) and how these factors influenced the diagnosis of white-coat hypertension in the hypertensive subjects. PATIENTS AND METHODS: We examined 44 white-collar workers with untreated, uncomplicated mild hypertension, mean age 35 years, twice using 24 h BPM: on the day of natural activity, at home and at work (work-day 24 h BPM); and on the fourth day of hospitalization (hospital-day 24 h BPM). RESULTS: The mean value of blood pressure during activity period in hospital (hospital-day blood pressure) wqas significantly lower than that for ambulatory monitoring day (work-day blood pressure; 132/82 versus 138/85 mmHg). For work-day 24 h BPM the mean systolic blood pressure (SBP) and diastolic blood pressure (DBP) from the period 0800-1600 h were substantially higher than the values from 1600-2300 h; for hospital-day 24 h BPM the mean SBP and DBP from two parallel activity periods did not differ significantly. The average office blood pressure of outpatients was 147.9 mmHg for SBP and 92.4 mmHg for DBP. Using the same threshold value of work-day and hospital-day blood pressures < 135/85 mmHg, the prevalence of white-coat hypertension was higher during a hospital day than it was on the work day. Basing our analysis of work-day 24 h BPM, white-coat hypertension was diagnosed in 28% of patients; basing our analysis on hospital-day 24 h BPM it was diagnosed in 49% of patients. mean night SBP and DBP at home and at hospital did not differ significantly. The correlation coefficients for relationship between home-night and hospital-night blood pressures were higher than those for work-day and hospital-day blood pressures (0.6 versus 0.44 for SBP; 0.63 versus 0.56 for DBP).CONCLUSIONS: Modification of the environmental conditions during activity period of men with mild hypertension causes an essential change in values and rhythm of blood pressure during this period, but does not influence the mean night blood pressure. Disregarding this fact during clinical interpretation of the results of 24 h BPM, especially with this group of patients, might be the main cause of a significant mistake in diagnosing white-coat hypertension.