P2C242: Preterm Birth, Low Birth Weight, and Hypertension Severity in Youth Referred for Hypertension Disorders: A SUPERHERO Interim Analysis

Background: Youth-onset hypertension (HTN) is an increasing public health concern with both short and long-term negative consequences. Previous research has shown that youth who were born preterm ( < 37 weeks’ gestation) or with low birth weight (LBW, < 2500 g) have an increased risk of HTN. However, it is unknown if preterm birth or LBW are associated with more severe HTN once diagnosed. The objective of this study is to determine whether youth referred for HTN disorders who were born preterm or had LBW have an increased risk of worse blood pressure (BP) or target organ injury (TOI).

Methods: This is a cross-sectional analysis of preliminary baseline data from The Study of the Epidemiology of Pediatric Hypertension (SUPERHERO) Registry, an ongoing multisite retrospective cohort of youth referred to specialty clinics for HTN disorders. Inclusion criteria were < 19 years of age, initial visit between 1/01/2015–12/31/2021 (index date), and ICD-10 diagnostic codes for HTN disorders. Exclusion criteria were pregnancy, kidney failure on dialysis, or kidney transplantation by ICD-10 codes. We classified BP and defined HTN based on age, sex, and height per pediatric guidelines. Preterm birth, LBW, TOI, and growth restriction were based on ICD-10 codes at the index date. The sample size of those with ICD-10 codes for growth restriction was too small so it was omitted from the final analysis. Statistical analyses included the Welch two-sample t-test and unadjusted generalized linear models.

Results: Of the 12,148 participants, 23% identified as Black/African American, 13% as Hispanic/Latino, 40% were female, and the mean age was 11.6 years (SD 5.2). Only 39/12148 (0.3%) had an ICD-10 code for preterm birth, 35/12148 (0.3%) had an ICD-10 code for LBW, and 48% had stages 1 or 2 HTN. Participants born preterm had significantly lower SBP compared to those without preterm birth (-16 mmHg, 95% CI -23 to -9.2). Participants with LBW had significantly lower SBP and DBP compared to those without LBW (-9.2 mmHg, 95% CI -15 to -3.2 and -13 mmHg, 95% CI -22 to -3.1). Preterm birth and LBW were not associated with a higher risk of HTN severity or with prevalence of TOI (RR 0.77, 95% CI 0.38 to 1.60 & RR 2.15, 95% CI 0.84 to 6.58).

Conclusion: Youth referred for HTN disorders who had ICD-10 codes for preterm birth had lower SBP and those who had ICD-10 codes for LBW had lower SBP and DBP. There was no difference in risk of TOI. It is possible that preterm birth and LBW are not accurately documented through ICD-10 codes. Ongoing analyses include obtaining actual gestational age at birth, birth weight, and laboratory and echocardiogram data.