Abstract MP42: Do Adult Ambulatory BP Cut-points Predict Target Organ Damage Better Than Pediatric ABP Percentiles?

Ambulatory hypertension (HT) is more strongly related to cardiac target organ damage (TOD) than clinic BP. Therefore, correct classification of ambulatory blood pressure (ABP) phenotype is needed to determine which patients to refer for imaging. Pediatric ABPM interpretation is based on percentiles of ABP while adult ABPM interpretation is based on static cut-points. We sought to determine which ABP classification system was the best predictor of TOD in adolescents. We measured adiposity, LV mass index (LVMI), systolic and diastolic function (strain, E/e’ ratio) in 315 adolescents (15.9 + 1.4 years, 64% white, 59% male). BP phenotype was determined by mean of 6 casual aneroid SBPs, and 24-hour SBP on ABP (Spacelabs Inc., Snoqualmie, WA) 1) by age, sex and height specific pediatric cut-points and 2) by adult ABPM cut-points (day &lt;130, night &lt; 110, 24-hour &lt; 125 mmHg). We evaluated concordance in classification and prevalence of TOD with Chi square and kappa statistic for agreement. For daytime SBP, 5% of all subjects (16 of 315) reclassified from normotensive (NT) to masked hypertension (MH) and 8% (24 of 315) reclassified from white coat (WC) to HT. Results were similar for night and 24-hour ABP. Fewer NT and WC subjects had any form of TOD by adult vs pediatric cut-point (NT 32 vs 36%, WC 8 vs 13%; chi square &lt; 0.0001, kappa 0.73). The only significant differences in cardiac TOD by ABP phenotype were found using adult ABP cut-points (LVMI higher and strain lower HT vs NT, diastolic E/e’ higher HT and MH vs NT all p &lt;=0.05). We conclude that classification of ABP by adult cut-points is superior in identifying adolescents at risk for cardiac TOD. These findings may inform future pediatric ABP guidelines. </jats:p

Machine Learning–Based Prediction of Masked Hypertension Among Children With Chronic Kidney Disease

Background: Ambulatory blood pressure monitoring (ABPM) is routinely performed in children with chronic kidney disease to identify masked hypertension, a risk factor for accelerated chronic kidney disease progression. However, ABPM is burdensome, and developing an accurate prediction of masked hypertension may allow using ABPM selectively rather than routinely. Methods: To create a prediction model for masked hypertension using clinic blood pressure (BP) and other clinical characteristics, we analyzed 809 ABPM studies with nonhypertensive clinic BP among the participants of the Chronic Kidney Disease in Children study. Results: Masked hypertension was identified in 170 (21.0%) observations. We created prediction models for masked hypertension via gradient boosting, random forests, and logistic regression using 109 candidate predictors and evaluated its performance using bootstrap validation. The models showed C statistics from 0.660 (95% CI, 0.595–0.707) to 0.732 (95% CI, 0.695–0.786) and Brier scores from 0.148 (95% CI, 0.141–0.154) to 0.167 (95% CI, 0.152–0.183). Using the possible thresholds identified from this model, we stratified the dataset by clinic systolic/diastolic BP percentiles. The prevalence of masked hypertension was the lowest (4.8%) when clinic systolic/diastolic BP were both &lt;20th percentile, and relatively low (9.0%) with clinic systolic BP&lt;20th and diastolic BP&lt;80th percentiles. Above these thresholds, the prevalence was higher with no discernable pattern. Conclusions: ABPM could be used selectively in those with low clinic BP, for example, systolic BP&lt;20th and diastolic BP&lt;80th percentiles, although careful assessment is warranted as masked hypertension was not completely absent even in this subgroup. Above these clinic BP levels, routine ABPM remains recommended. </jats:sec

Mean Arterial Pressure and Chronic Kidney Disease Progression in the CKiD Cohort

Consensus blood pressure guidelines vary in their recommended ambulatory blood pressure targets for children with chronic kidney disease (CKD) because of limited research in this area. We analyzed longitudinal ambulatory blood pressure monitoring data from 679 children with moderate CKD enrolled in the observational CKiD (Chronic Kidney Disease in Children) cohort by time-varying mean arterial pressure (MAP) percentile categories based on the highest wake or sleep MAP percentile. Analyses were stratified by nonglomerular and glomerular diagnoses, with 3 models constructed: unadjusted, adjusted for age, sex, and race, and additional adjustment for proteinuria. The outcome of interest was time to renal replacement therapy or 50% decline in baseline renal function. We found that among children with nonglomerular CKD, MAP percentile was not associated with accelerated disease progression risk until after 4 years of follow-up at which point a high MAP (&gt;90th percentile) was associated with a higher risk of progression to the composite end point (HR, 1.88 [CI, 1.03–3.44]). Among those with glomerular CKD, differential risk for progression began from baseline with the highest risk in those with MAP &gt;90th percentile (HR, 3.23 [CI, 1.34–7.79]). These relationships were attenuated somewhat after adjustment for level of proteinuria, but the trend for higher MAP being associated with higher risk of progression remained significant. Thus, in children with CKD, having ambulatory wake or sleep MAP &gt;90th percentile was associated with higher risk of kidney disease progression with the highest levels of MAP associated with the greatest risk of progression. Registration: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT00327860 </jats:sec