Nocturnal Dipping and Left Ventricular Mass Index in the Chronic Kidney Disease in Children Cohort.

Background and Objectives: The physiologic nocturnal BP decline is often blunted in patients with CKD; however, the consequences of BP nondipping in children are largely unknown. Our objective was to determine risk factors for nondipping and to investigate if nondipping is associated with higher left ventricular mass index in children with CKD.
Design, Setting, Participants, & Measurements: We conducted a cross-sectional analysis of ambulatory BP monitoring and echocardiographic data in participants of the Chronic Kidney Disease in Children study. Multivariable linear and spline regression analyses were used to evaluate the relationship of risk factors with dipping and of dipping with left ventricular mass index.
Results: Within 552 participants, mean age was 11 (±4) years, mean eGFR was 53 (±20) ml/min per 1.73 m ² , and 41% were classified as nondippers. In participants with nonglomerular CKD, female sex and higher sodium intake were significantly associated with less systolic and diastolic dipping ( P ≤0.05). In those with glomerular CKD, Black race and greater proteinuria were significantly associated with less systolic and diastolic dipping ( P ≤0.05). Systolic dipping and diastolic dipping were not significantly associated with left ventricular mass index; however, in spline regression plots, diastolic dipping appeared to have a nonlinear relationship with left ventricular mass index. As compared with diastolic dipping of 20%-25%, dipping of <20% was associated with 1.41-g/m ^2.7 -higher left ventricular mass index (95% confidence interval, -0.47 to 3.29), and dipping of >25% was associated with 1.98-g/m ^2.7 -higher left ventricular mass index (95% confidence interval, -0.77 to 4.73), although these relationships did not achieve statistical significance.
Conclusions: Black race, female sex, and greater proteinuria and sodium intake were significantly associated with blunted dipping in children with CKD. We did not find a statistically significant association between dipping and left ventricular mass index.
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