Association of blood pressure variability and neurocognition in children with chronic kidney disease

Background Children with chronic kidney disease (CKD) and hypertension have increased blood pressure variability (BPV), which has been associated with lower neurocognitive test scores in adults. Children with CKD are at risk for decreased neurocognitive function. Our objective was to determine whether children with CKD and increased BPV had worse performance on neurocognitive testing compared with children with CKD and lower BPV. Methods This was a cross-sectional and longitudinal analysis of the relation between BPV and neurocognitive test performance in children >= 6 years enrolled in the Chronic Kidney Disease in Children (CKiD) study. Visit-to-visit BPV was assessed by the standard deviation of visit BPs (BPV-SD) and average real variability (ARV). Ambulatory BPV was assessed by SD of wake and sleep periods on 24-h ambulatory BP monitoring. Results We assessed 650 children with a mean follow-up period of 4.0 years. Children with systolic visit-to-visit BPV in the upper tertile had lower scores on Delis-Kaplan Executive Function System (D-KEFS) Verbal Category Switching than those with BPV in the lower tertile (BPV-SD, 8.3 vs. 9.5, p = 0.006; ARV, 8.5 vs. 9.6, p = 0.02). On multivariate analysis, the association between lower Category Switching score and increased BPV remained significant after controlling for mean BP, demographic characteristics, and disease-related variables [BPV-SD, beta = -0.7, 95 % confidence interval (CI) -1.28 to -0.12; ARV, beta = -0.54, CI -1.05 to -0.02). Ambulatory BPV was not independently associated with any cognitive measure. Conclusions Higher systolic visit-to-visit BPV was independently associated with decreased D-KEFS Category Switching scores in children with mild-to-moderate CKD.