Long-term kidney outcomes in children and adolescents with hypertension: a propensity-matched cohort study

Hypertension affects 6% of all children and adolescents, is increasing in prevalence, and is associated with adverse cardiovascular outcomes. In childhood chronic kidney disease, hypertension is associated with progression to kidney failure. However, direct evidence linking childhood hypertension with long-term adverse kidney outcomes is scarce. We aimed to determine the long-term risk of major adverse kidney events (MAKEs) among children and adolescents diagnosed with hypertension.

In this population-based retrospective cohort study, we assessed data from all children and adolescents (aged 3-18 years) diagnosed with hypertension from April 1, 1996, to March 31, 2023, in Ontario, Canada, using validated case definitions in health administrative databases. Each case was propensity score-matched with up to five controls without hypertension by age, sex, birthweight, maternal gestational hypertension, pre-existing diabetes, previous cardiovascular surgery, obesity, previous acute kidney injury, and a propensity score for hypertension diagnosis. The primary outcome was major adverse kidney events (MAKEs; ie, all-cause mortality, incident chronic kidney disease, or kidney failure defined as start of chronic dialysis or receipt of kidney transplantation), assessed using weighted Cox regression using robust variance estimators to estimate hazard ratios (HRs) and 95% CIs.

26 324 children and adolescents with hypertension were matched with 126 834 controls without hypertension, who were balanced on baseline covariates by propensity score matching. For children and adolescents with hypertension, median age at entry was 15 years (IQR 12-17), there were 10 868 (41·3%) females and 15 456 (58·7%) males, and previous personal and maternal comorbidities were uncommon (1169 [4·4%] had congenital heart disease, 1787 [6·8%] malignancy, 432 [1·6%] diabetes, 2356 [9·0%] complex chronic conditions, and 379 [3·0%] born to mothers with hypertension). During a median 14·2-year follow-up (IQR 7·4-20·7) in the hypertension cohort and 13·7-year follow-up (7·1-21·2) among controls, MAKE incidence was 5·52 per 1000 person-years (95% CI 5·28-5·76) in children and adolescents with hypertension versus 1·66 per 1000 person-years (1·60-1·72) in matched non-hypertensive controls (7·7% vs 2·4%; HR 3·03 [95% CI 2·86-3·21]).

Children and adolescents diagnosed with hypertension are at greater long-term risk of MAKEs compared with non-hypertensive controls. Improved recognition and control of paediatric hypertension might prevent progressive kidney dysfunction. These findings should be confirmed by large-scale, well-controlled prospective studies.

Department of Pediatrics at McMaster University.