Relationship between circadian rhythm of blood pressure and renal failure severity in patients with chronic renal failure

Blood pressure decreases during sleep and is markedly increased in the morning in healthy individuals. Lack of nocturnal blood pressure fall (non-dipping) has been associated with cardiovascular morbidity, mortality and other organ damage. However, their importance in chronic renal failure is unclear. This study aimed to investigate relationship between circadian rhythm of blood pressure and renal failure severity in patients with chronic kidney disease.
This cross-section study was done in April 2016. The study population was 95 patients, more than 30 year old with hypertension and chronic renal failure. Patients were selected from clinics of two private and university hospitals affiliated to Qom University of Medical Sciences Shahid Beheshti Hospital and Vali-e-Asr Hospital, Iran. Checklist containing data such as age, sex, duration of renal failure and cause of renal failure were filled. Serum creatinine and serum urea levels were measured and entered in the checklist. The circadian rhythm of blood pressure in all patients was assessed by Holter monitoring. patients who had less than 10% decrease in blood pressure overnight were considered non-dipper and those who had 10% or more decrease in blood pressure overnight were considered dipper.
Average (SD) 24-hour ambulatory systolic and diastolic of blood pressure was 136.56 (16.66) and 84.84 (10.86) mmHg, respectively. 70 patients (73.7%) had non-dipper blood pressure pattern and 25 patients (26.3%) had dipper blood pressure pattern. There was no significant difference between two groups (dipper and non-dipper) based on distribution of gender (P=0.744), age (P=0.407), serum creatinine (P=0.569), serum urea (P=0.689) and renal failure duration (P=0.812). Mean of glomerular filtration rate in dipper group was 68.64±4.13 and in non-dipper group was 65.09±16.27 (P=0.337).
The results of this study did not show a significant relationship between circadian rhythm of blood pressure and renal failure severity. In addition, patients with chronic renal failure showed higher rates of non-dipping pattern of blood pressure.