Myths and reality concerning hypertension in peritoneal dialysis patients: results of a multicenter study

OBJECTIVES: To evaluate the prevalence of hypertension, the average blood pressure level, the 24 h blood pressure profile, and the efficacy of antihypertensive therapy for a large population of peritoneal dialysis patients.DESIGN: A cross-sectional, observational multicenter study. METHODS: From 504 peritoneal dialysis patients (18% of the Italian peritoneal dialysis population) involved in a multicenter observational study, we selected 414 who had undergone successful ambulatory blood pressure monitoring (i.e. no hours with data absent, >/= 75% successful readings and monitoring duration >/= 24 h). Office blood pressure measurements and ambulatory blood pressure monitoring were performed for each patient on the same day with a standard mercury sphygmomanometer and a SpaceLabs 90207 device, respectively.RESULTS: According to World Health Organization/International Society of Hypertension criteria, 44 peritoneal dialysis patients (10.6%) were normotensive and 370 patients (89.4%) were hypertensive, 304 (82.1%) of whom were being administered antihypertensive therapy. Daytime systolic and diastolic blood pressures were both significantly lower than office systolic and diastolic blood pressures (140.7 +/- 19.7/72.1 +/-11.1 versus 148.3 +/- 23.6/85.6 +/- 12 mmHg; P < 0.001). The difference between office blood pressure and daytime blood pressure was significantly correlated to office blood pressure (P < 0.001 for systolic and P < 0.001 for diastolic). The diurnal blood pressure rhythm evaluated by visual inspection of hourly mean plots was not influenced by sex, age, antihypertensive treatment, and peritoneal dialysis modality. Systolic and diastolic blood pressures exhibited a day-night mean decreases of 8.6 +/- 11.7 and 7.7 +/- 6.9 mmHg, respectively, and daytime blood pressure values were significantly higher than night-time ones (P < 0.001). Two hundred and twenty patients (53.1%) were nondippers according to O'Brien's criteria, 247 patients (59.7%) were nondippers according to Verdecchia's criteria, and 269 patients (65.0%) were nondippers according to Staessen's criteria. Only 39 patients (9.4%) had a reversed circadian rhythm. The day-night differences of systolic and diastolic blood pressures were in a unimodal distribution. Among hypertensive patients not being administered antihypertensive therapy, only six patients ( five women and one man) had white-coat hypertension. Among hypertensive patients being administered antihypertensive therapy, 235 patients (77.3%) had 24 h blood pressure loads > 30%.CONCLUSION: There is a high prevalence of hypertension among peritoneal dialysis patients. White-coat hypertension is very rare in this population. Despite the extensive use of antihypertensive therapy, control of blood pressure is maintained in a large number of our peritoneal dialysis patients. Any classification of patients into dipers and nondippers must be interpreted cautiously.