SAT-325 RELATIONSHIP AND PATTERN BETWEEN AMBULATORY BLOOD PRESSURE MONITORING PARAMETERS AND ESTIMATED GLOMERULAR FILTRATION RATE IN CHILDREN WITH GLOMERULAR AND NON-GLOMERULAR CONDITIONS

Abstract

Ambulatory blood pressure monitoring (ABPM) is an important tool for evaluation of blood pressure (BP) among high risk children including those with renal diseases. Our study aimed to describe and compare the ABPM parameters between children with glomerular and non-glomerular renal conditions, and explore the relationship between the various ABPM parameters and the estimated glomerular filtration (eGFR). We performed a cross-sectional review of the office BP records and ABPM reports of children followed up in the paediatric nephrology clinic of Queen Elizabeth Hospital, Hong Kong from year 2013-2017. ABPM reports with <70% success rate were excluded. Among subjects with ≥1 ABPM reports, only the first available report was included for analysis. The renal diagnosis was categorized into glomerular diseases and non-glomerular disease comprising congenital anomalies of kidney and urinary tract (CAKUT), cystic kidney diseases, renovascular hypertension, neurogenic bladder / bladder dysfunction and other conditions. Altogether there were 67 patients included in the final analysis. The median age (interquartile range) of the cohort was 14.5 (5.4) years and the median BMI was 19.3 (5.0) kg/m2. Glomerular diseases accounted for 23.9% of all renal conditions and the median eGFR of the whole cohort was 96.3 (34.6) ml/min/1.73m (Table 1)2. There were 62.7% of subjects having ABPM hypertension (ABPM systolic or diastolic hypertension in either wake or sleep periods), and 40.3% of subjects were non-dippers (nocturnal dipping <10%). Office BP hypertension was found in 35.9% of subjects and 25% of subjects had masked hypertension. Only 16.7% of subjects with ABPM hypertension were receiving anti-hypertensive medications. The baseline characteristics of subjects with glomerular and non-glomerular diseases showed no significant difference, and the ABPM parameters in both wake and sleep periods were comparable between the two groups (Table 2). Most subjects with non-glomerular diagnoses had no hypertension (35.4%), whereas ambulatory hypertension (both office BP hypertension and ABPM hypertension) was the commonest BP category (37.5%) among those with glomerular conditions (p=0.934) (Figure 1). The median eGFR of children with glomerular and non-glomerular diseases showed no significant difference (p=0.538). All systolic or diastolic BP indices and BP loads in wake and sleep periods showed a significantly inverse relationship with the eGFR among children with glomerular diseases (Table 3). The relationship was stronger for glomerular than non-glomerular conditions. A lower eGFR among children with glomerular disease could be observed in those having wake or sleep ABPM hypertension (systolic or diastolic) or ABPM hypertension, as well as non-dippers. And a significant difference could be found among those with wake period diastolic hypertension (p=0.036) and sleep period systolic hypertension (p=0.044). Masked hypertension and non-dippers were common among children with renal conditions and most children with ABPM hypertension were not receiving anti-hypertensives. Both the wake and sleep period ABPM parameters demonstrated a negative correlation with eGFR among children having glomerular diseases at a relatively normal eGFR. The results indicated that regular ABPM should be performed for children with renal conditions, even without chronic kidney disease.