Recent evidence suggests that pulse pressure (PP) is an independent predictor of cardiovascular risk. The objective of this study was to compare mean values and reproducibility of PP obtained in the clinic (CPP), at home (HPP) and with ambulatory monitoring (APP) and to evaluate potential implications for trials aiming to assess drug effects on PP.
A total of 393 hypertensive subjects [mean age 51.5 ± 11.5 (SD) years, 59% men, 35% treated] measured CPP (two visits), HPP (6 days) and APP (24 h). The reproducibility of PP was assessed using the SD of differences (SDD) between measurements in 133 untreated subjects who had repeated CPP (five visits), HPP (6 days) and APP measurements (two occasions).
There was no difference between mean CPP (51.0 ± 13.3 mmHg) and HPP (50.2 ± 11.0) whereas APP (48.8 ± 8.4) was lower than both CPP [mean difference 2.3 ± 10.3 mmHg; 95% confidence interval (CI), 1.2, 3.3;P< 0.01] and HPP (1.5 ± 7.8; 95% CI, 0.7, 2.3;P< 0.01). The SDD between repeated measurements was about 10 mmHg for CPP (one visit), 5.2 mmHg for HPP (2 days) and 4 mmHg for APP (24-h). For a parallel comparative trial aiming to detect a difference of 3 mmHg PP in the effect of two drugs, 415 subjects would be required when using CPP, compared to 127 using HPP and 63 using APP.
These data suggest that although differences among mean values of CPP, HPP and APP are small, differences in their reproducibility are important and should be taken into account in the design of trials assessing drug effects on PP.
Hypertension Center, Third University Department of Medicine, Sotiria Hospital, Athens, Greece.
Correspondence and requests for reprints to George S. Stergiou MD, Hypertension Center, Third University Department of Medicine, Sotiria Hospital, 152 Mesogion Ave, Athens 11527, Greece. Tel: +30 (1) 771 9975; fax: +30 (1) 771 9981; e-mail: firstname.lastname@example.org
Received 8 January 2002
Revised 26 April 2002
Accepted 10 June 2002