Effects of reduced blood pressure dipping on the progression of chronic kidney disease in children

Background: Hypertension is a common complication of chronic kidney disease (CKD) in children. It is related to the progression of CKD. However, current guidelines for hypertension management in CKD patients mainly focus on managing patients with above-target blood pressure. The effects of reduced nocturnal blood pressure dipping on CKD progression in children are poorly understood. Methods: This single-center, retrospective cohort study analyzed the clinical data of children with stage 2–5 non-dialysis CKD undergoing ambulatory blood pressure monitoring (ABPM), Clinical characteristics and laboratory parameters of children with and without hypertension and/or reduced nocturnal blood pressure dipping were analyzed. Results: Ninety-four children were included, with a median age of 10 years (interquartile range [IQR] 6–12 years), of whom 65 were male (69.1%). The median estimated glomerular filtration rate (eGFR) was 41 ml/min/1.73 m ² , and the median 24-hour proteinuria level was 637 mg. There were 41 (43.6%) cases of ambulatory BP at target and 53 (56.4%) cases of ambulatory hypertension. Nocturnal dipping without ambulatory hypertension was found in 10 cases (10.6%), nocturnal non-dipping without ambulatory hypertension in 31 cases (33.0%), nocturnal dipping with ambulatory hypertension in 5 cases (5.3%), and nocturnal non-dipping with ambulatory hypertension in 48 cases (51.1%). The nocturnal non-dipping with ambulatory hypertension group had the lowest hemoglobin (F=2.798, P=0.045), eGFR (F=3.228, P=0.026), and 25 (OH) D3 (F=3.428, P=0.023). During a median follow-up of 15 months (IQR 7–31 months), 27 patients (28.7%) showed a decrease in eGFR of >3 ml/min/1.73 m ² /year. Further, 21 patients (22.3%) progressed to end-stage kidney disease requiring kidney replacement therapy. The nocturnal non-dipping with ambulatory hypertension group had the highest risk of renal progression (hazard ratio [HR]=3.634; 95% confidence interval [CI], 0.866–15.258), while the nocturnal dipping with ambulatory hypertension group (HR=1.945; 95% CI, 0.273–13.865) had similar risks to the nocturnal non-dipping without ambulatory hypertension group (HR=1.584; 95% CI, 0.350–7.171). Multivariate Cox regression analysis revealed that persistent proteinuria and reduced nocturnal blood pressure dipping were associated with renal outcomes. Conclusion: Regardless of whether ambulatory blood pressure was normal, reduced blood pressure dipping was correlated with the risk of renal progression in children with CKD.