Circadian variation of blood pressure in patients with chronic renal failure on continuous ambulatory peritoneal dialysis

The circadian pattern of blood pressure variation was investigated in 10 patients with advanced chronic renal failure on continuous ambulatory peritoneal dialysis (CAPD) and in an age-matched group of controls without renal disease with similar office blood pressure level. Monitoring was done using a non-invasive ambulatory blood pressure recorder. Average 24-h blood pressure was significantly higher in the group of CAPD patients than in the group of healthy controls, i.e. 141 +/- 22/82 +/- 8 mmHg (systolic and diastolic blood pressure +/- SD) vs. 126 +/- 18/80 +/- 7, p < 0.1. This was a result of abnormal 24-h blood pressure profiles among CAPD patients. In the group of controls these profiles were in accordance with the established normal pattern, whereas nocturnal blood pressure reductions were significantly less pronounced in the patient group. The reduction +/- SD in the mean arterial blood pressure was 2 +/- 6 mmHg in patients versus 10 +/- 5 mmHg in controls, p < 0.01. The mean arterial blood pressure values during daytime (0800-2000 h) exceeded the night time values (2000-0800 h) in all healthy controls, whereas four of 10 patients had higher blood pressure values during the night time. In patients with chronic renal failure undergoing CAPD, an otherwise unnoticed 24-h hypertension and nocturnal blood pressure elevation can be discovered by use of 24-h blood pressure monitoring and this may indicate a need of earlier start of antihypertensive treatment in CAPD patients with borderline daytime hypertension.