Reliability of resting blood pressure measurement and classification using an oscillometric device in children with chronic kidney disease.

Objective: To compare the reliability of blood pressure (BP) readings obtained with an oscillometric device with those obtained by auscultation and assess for differences in BP status classification based on the 2 techniques.
Study Design: Resting BP was measured by auscultation and with an oscillometric device at the same encounter in 235 subjects enrolled in the Chronic Kidney Disease in Children study. Resting auscultatory BP values were averaged and compared with averaged oscillometric readings. BP agreement by the 2 methods was assessed using Bland-Altman plots, and BP status classification agreement was assessed by calculation of kappa statistics.
Results: Oscillometric BP readings were higher than auscultatory readings, with a median paired difference of 9 mm Hg for systolic BP (SBP) and 6 mm Hg for diastolic BP (DBP). Correlation for mean SBP was 0.624 and for mean DBP was 0.491. The bias for oscillometric BP measurement was 8.7 mm Hg for SBP (P < .01) and 5.7 mm Hg for DBP (P < .01). BP status classification agreement was 61% for SBP and 63% for DBP, with Kappa values of .31 for SBP and .20 for DBP.
Conclusions: Compared with auscultation, the oscillometric device significantly overestimated both SBP and DBP, leading to frequent misclassification of BP status.
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