Introduction:
24-hour ambulatory blood pressure monitoring helps to identify the blood pressure variability and non-dipping/ reverse dipping status which are strong predictors of adverse cardiovascular outcomes. We designed this study to determine the ambulatory blood pressure profile and to find out the factors affecting blood pressure variability and nocturnal non dipping in patients with chronic kidney disease on continuous ambulatory peritoneal dialysis.
Methods:
Patients with chronic kidney disease, with age above 18 years and who were on continuous ambulatory peritoneal dialysis for more than at least 6 weeks, being followed up at a tertiary care centre in South India between August 2018 and January 2019 were recruited. Baseline demographic data were collected, and a standardised 4-hour peritoneal equilibration test was done to characterise the peritoneal membrane transport status. Adequacy of CAPD was calculated by measuring the combined (renal and peritoneal) Kt/V. Blood pressure using ABPM machine was recorded every 30 minutes during the day and every hour during the night.24 hours blood pressure variability was expressed as average real variability (ARV). Non dipping BP was defined as a fall in nocturnal BP of <10% and was found out for both systolic and diastolic BP. Univariable logistic regression analysis was performed to determine which risk factors were associated with non-dipper status and significant difference in mean blood pressure variability. P value less than 0.05 was taken as significant.
Results:
Patients had a higher mean systolic and diastolic BP on ambulatory blood pressure monitoring, when compared to office BP measurements (148.2±18.8 mm of Hg and 84.9±6.1 mm of Hg). In 24-hour ABPM measurements, mean systolic BP was 160.0±22.0 mm of Hg with a mean variability of 17.5±7.3 mm of Hg and a mean diastolic BP was 87.5±15.4 mm of Hg with a mean variability of 11.3±4.7 mm of Hg. 26 patients (81.3%) had non-dipping of systolic BP, while 30 patients (93.8%) had non dipping of diastolic BP. The risk factors for nocturnal nondipping were a total volume of 24-hour urine output and 24-hour ultrafiltrate less than 1 litre (p value:0.03, 95% CI 0.841-0.996) and use of calcium channel blockers(C) (p value:0.038, 95% CI 0.764-0.998). The mean BP variability was found to be higher in those taking beta blockers (21.1±7.3 vs 14.2±5.8 p value 0.006) and central sympatholytic class of antihypertensives (20.1±8.0 vs 14.1±4 p value 0.018) when compared to those not taking. Age, sex, body mass index, dialysis vintage, peritoneal membrane transport status and dialysis adequacy did not have an association with non-dipping status and did not affect the mean BP variability.
Conclusions:
Ambulatory blood pressure monitoring is crucial in detecting the non-dipping status and and mean BP variability in patients on continuous ambulatory peritoneal dialysis. A combined volume of net peritoneal ultrafiltration and urine output less than 1 litre can be a risk factor for nocturnal non dipping, hence adequate ultrafiltration and preservation of residual urine output is crucial for adequate blood pressure control in these patients. The class of antihypertensives used can have an effect on non-dipping status and blood pressure variability, which needs further research.
I have no potential conflict of interest to disclose.
I did not use generative AI and AI-assisted technologies in the writing process.