CAPD patients exhibit a nocturnal fall in blood pressure: a single-centre study.
BACKGROUND
In 29 CAPD (continuous ambulatory peritoneal dialysis) patients the height and diurnal variation of the blood pressure (BP) and heart-rate (HR) were analyzed by means of 24-hour ambulatory blood pressure monitoring (ABPM).


METHODS
Normal diurnal variation was defined as a fall of 10% or more during nighttime (NT) compared with daytime (DT) BP or HR (DT = 10.00 a.m.-9.00 p.m., NT = midnight-06.00 a.m.). To evaluate high BP in the course of time we used the concept of "whole-day BP load", defined as the percentage of BP readings above 140/90 mmHg during a 24-h period. A "hypertensive BP load" was defined as a systolic BP (SBP) load of more than 50% and/or a diastolic BP (DBP) load in excess of 40%. In addition to analysis of the circadian rhythm of BP and HR and the prevalence of a hypertensive BP load in CAPD patients, the influence of various factors such as gender, creatinine clearance, recombinant human erythropoietin, antihypertensive medication, haematocrit, whole-day BP load, and the nightly dialysis glucose concentration on the diurnal variation of BP and HR were studied.


RESULTS
Based on the 95% confidence intervals for the proportional nocturnal decrease, normal diurnal variation of BP and HR was present in most CAPD patients. No correlation could be demonstrated between a blunted circadian rhythm and the variables mentioned above. However, when other time-period definitions (DT = 6.00 a.m.-11.00 p.m., NT = 11.00-6.00 and DT = 8.00 a.m.-8.00 p.m., NT = 8.00 p.m.-8.00 a.m.) were applied to the data, considerably fewer patients displayed normal diurnal variation. Whereas all patients showed normal home BP readings, ABPM of 21 out of 29 patients displayed a hypertensive BP load.


CONCLUSIONS
The majority of our CAPD patients exhibited normal diurnal variation of SBP and DBP depending, however, on the definitions of DT and NT used. The absence of a normal circadian rhythm could not be explained by any of the variables analyzed. Surprisingly, uncontrolled hypertension, as defined by a hypertensive BP load, was found in 72% of the patients.
Heebels
A E
AE
Department of Nephrology and Dialysis, Medical Center Alkmaar, Netherlands.
Nubé
M J
MJ
van Limbeek
J
J
Grooteman
M P
MP
van Geelen
J A
JA
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000959:Antihypertensive Agents / Q000627:therapeutic use; D001794:Blood Pressure; D015924:Blood Pressure Monitors; D002940:Circadian Rhythm; D016001:Confidence Intervals; D003971:Diastole; D005260:Female; D006339:Heart Rate; D006801:Humans; D006973:Hypertension / Q000188:drug therapy; D008297:Male; D008875:Middle Aged; D010531:Peritoneal Dialysis, Continuous Ambulatory; D013599:Systole
D000959:Antihypertensive Agents