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Hypertension affects 6% of all children and its prevalence is increasing. Pediatric hypertension tracks into adulthood and is associated with subclinical cardiovascular disease. However, there is limited direct evidence linking pediatric hypertension to long-term cardiovascular outcomes, contributing to under-diagnosis and -treatment. Our aim was to determine the long-term risk of cardiovascular outcomes among children with hypertension.
Retrospective cohort study of all children (3-18 years) with an incident hypertension diagnosis from 1996-2021 in Ontario, identified using provincial administrative health databases with validated case definitions. Children with prior hypertension or kidney replacement therapy were excluded. Each case was matched with five pediatric controls without hypertension by age, sex, birthweight, maternal gestational hypertension, prior co-morbidities (chronic kidney disease, diabetes mellitus, and cardiovascular surgery), and a propensity score for hypertension. Children were followed until death (0.7%), provincial emigration (11.2%), or March 2022 (88.1%). The primary outcome was major adverse cardiac events (MACE; a composite of cardiovascular death, stroke, myocardial infarction or unstable angina hospitalization, or coronary intervention). Secondary outcomes were individual cardiovascular events, cardiovascular procedures, and all-cause mortality.
A total of 25,605 children with hypertension were matched to 128,025 non-hypertensive controls. Baseline covariates were well-balanced after propensity score matching. Median age was 15 years (IQR 11-17), 42% were female, and prior co-morbidities were uncommon (4% congenital heart disease, 6% malignancy, and 2% diabetes). During median 12.9-year (IQR 6.8-19.8) follow-up, the incidence rate (IR) of MACE was 5.4/1000 person-years (py) in children with hypertension vs. 1.5/1000py in controls (adjusted hazard ratio (aHR) 2.1, 95%CI 1.9-2.2, p<0.001). Children with hypertension were at increased risk of all-cause mortality (IR 2.7 vs. 0.5/1000py; aHR 1.9, 95%CI 1.7-2.0), congestive heart failure (IR 2.2 vs. 0.3/1000py; aHR 2.6, 95%CI 2.4-2.9), and cardiovascular procedures (IR 2.3 vs. 0.4/1000py; aHR 2.6, 95%CI 2.3-2.8) vs. non-hypertensive controls.
Children with hypertension are at higher long-term risk of adverse cardiovascular outcomes vs. non-hypertensive controls. This justifies improved screening and management of pediatric hypertension, to prevent complications. These findings should be confirmed by large-scale, well-controlled prospective studies.