Evaluation of administrative case definitions for hypertension in Canadian children

Long-Term Cardiovascular Outcomes in Children and Adolescents With Hypertension

Importance

Hypertension affects 6% of all children, and its prevalence is increasing. Childhood hypertension tracks into adulthood and is associated with subclinical cardiovascular disease; however, there is a lack of evidence linking childhood hypertension to cardiovascular outcomes, which may contribute to underdiagnosis and undertreatment.

Objective

To determine the long-term associated risk of major adverse cardiac events (MACE) among children diagnosed with hypertension.

Design, Setting, and Participants

This was a population-based, retrospective, matched cohort study conducted from 1996 to 2022. The study included all children (aged 3-18 years) alive in Ontario, Canada, from 1996 to 2021, who were identified using provincial administrative health databases. Children with prior kidney replacement therapy were excluded.

Exposure

Incident hypertension diagnosis, identified by validated case definitions using diagnostic and physician billing claims. Each case was matched with 5 controls without hypertension by age, sex, birth weight, maternal gestational hypertension, prior comorbidities (chronic kidney disease, diabetes, cardiovascular surgery), and a propensity score for hypertension.

Main Outcomes and Measures

The primary outcome was MACE (a composite of cardiovascular death, stroke, hospitalization for myocardial infarction or unstable angina, or coronary intervention). Time to MACE was evaluated using the Kaplan-Meier method and Cox proportional hazards regression.

Results

A total of 25 605 children (median [IQR] age, 15 [11-17] years; 14 743 male [57.6%]) with hypertension were matched to 128 025 controls without hypertension. Baseline covariates were balanced after propensity score matching, and prior comorbidities were uncommon (hypertension vs control cohort: malignancy, 1451 [5.7%] vs 7908 [6.2%]; congenital heart disease, 1089 [4.3%] vs 5408 [4.2%]; diabetes, 482 [1.9%] vs 2410 [1.9%]). During a median (IQR) of 13.6 (7.8-19.5) years of follow-up, incidence of MACE was 4.6 per 1000 person-years in children with hypertension vs 2.2 per 1000 person-years in controls (hazard ratio, 2.1; 95% CI, 1.9-2.2). Children with hypertension were at higher associated risk of stroke, hospitalization for myocardial infarction or unstable angina, coronary intervention, and congestive heart failure, but not cardiovascular death, compared with nonhypertensive controls.

Conclusions and Relevance

Children diagnosed with hypertension had a higher associated long-term risk of MACE compared with controls without hypertension. Improved detection, follow-up, and control of pediatric hypertension may reduce the risk of adult cardiovascular disease.

Temporal Trends in Practice Patterns After Introduction of Pediatric Hypertension Guidelines in Canada

Importance

In 2016 and 2017, respectively, new Canadian and US guidelines for diagnosis and management of pediatric hypertension (HTN) were published. Six years after their publication, it is unknown whether the recommendations have led to changes in primary care practice patterns.

Objectives

To determine whether HTN guidelines are associated with changes in practice patterns among primary care clinicians.

Design, Setting, and Participants

This retrospective, multicenter, population-based cohort study was conducted across 3 phases: January 1, 2011, to December 31, 2015 (era 1), January 1, 2016, to December 31, 2017 (washout period), and January 1, 2018, to December 31, 2019 (era 2). Data were collected from 7 Canadian provinces using the Canadian Primary Care Sentinel Surveillance Network Electronic Medical Record database. Eligible participants included children and adolescents (aged ≥3 to <18 years) with 1 or more encounters in the database. Data analysis was conducted from February 2022 to February 2023.

Exposure

Implementation of the 2016 Hypertension Canada and 2017 American Academy of Pediatrics guidelines.

Main Outcomes and Measures

The primary outcomes were annual BP screening documentation, high BP follow-up documentation at 6 months and 1-year, HTN prevalence, laboratory testing rates, and medication prescription rates. Interrupted time series analysis was used to assess the association of the introduction of the Canadian and US guidelines with outcomes.

Results

The study included 343 191 children and adolescents (mean [SD] age at first encounter, 6.7 (4.6) years; 173 290 female [50.5%]; 169 901 male [49.5%]), including 235 094 patients in era 1 and 193 473 patients in era 2. In era 1, 55 550 patients (23.6%) had at least 1 BP measurement, and in era 2, 45 006 patients (23.3%) had at least 1 BP measurement. There was a significant increase in BP screening in era 2 from 26 876 of 148 554 screenings (18.1%) to 28 556 of 141 192 screenings (20.2%; β = 0.202; 95% CI, 0.009 to 0.390; P = .04), and the increasing trend was sustained. There was a significant decrease in the trend of follow-up of high BP measurement at 6 months (1265 of 4941 patients with BP measurements [25.6%] to 1718 of 7321 patients with BP measurements [23.5%]; β = -0.490; 95% CI, -0.758 to -0.223; P = .001) and 1 year (1974 of 4941 measurements [40.0%] to 2314 of 7321 measurements [31.6%]; β = -1.392; 95% CI, -1.573 to -1.212; P < .001) in era 2. The proportion of patients meeting HTN criteria significantly increased from 2540 of 55 550 patients (4.6%) in era 1 to 5690 of 45 006 patients (12.6%) in era 2 (β = 0.0210; 95% CI, 0.0021 to 0.0410; P = .03). There was no significant change in the trend of laboratory testing rates in era 2 (949 of 4941 patients tested [19.2%] to 1149 of 7321 patients tested [15.7%]; β = -0.159; 95% CI, -0.364 to 0.046; P = .12). The trend in prescribing of medications to patients with HTN also decreased in era 2 (1305 of 4941 patients prescribed medication [26.4%] to 1415 of 7321 patients prescribed medication [19.3%]; β = -0.605; 95% CI, -0.830 to -0.358; P < .001).

Conclusions and Relevance

The findings of this cohort study within the Canadian primary care setting suggest that there was a significant increase in BP screening and HTN prevalence after the publication of national and international HTN guidelines; however, the follow-up of high BP was still suboptimal. Increasing rates of pediatric HTN emphasize the need for better adherence to pediatric HTN guidelines to improve care and outcomes.