Extreme preterm birth linked to hypertension at school age

1. Within a cohort of infants born extremely preterm (EPT), there were elevated rates of high systolic blood pressure (SBP≥90%ile) and hypertension (SBP≥95%ile) when these children reached school age.

2. School age children with high SBP who were born EPT, were significantly more likely to have been born to mothers with gestational diabetes, and as children, were more likely to have higher body mass indices (BMIs), larger waist circumference, and greater triceps skinfolds.

Evidence Rating Level: 1 (Excellent)

Study Rundown: Preterm infants are at increased risk of developing high systolic blood pressure (SBP≥90%ile) and hypertension (SBP≥95%ile) as they age. The purpose of this study was to evaluate rates of high SBP and hypertension in former EPT infants, defined as infants born <28 weeks’ gestation, at 6-7 years of age. This prospective study was completed as a subgroup analysis of the Surfactant Positive Airway Pressure and Pulse Oximetry Randomized Trial (SUPPORT), a multicenter randomized controlled trial that investigated ventilation and oxygenation strategies in EPT infants. Their data showed that approximately 1/5 of former EPT infants studied had high SBP and 1/10 had hypertension at 6-7 years of age. Maternal factors associated with high SBP and/or hypertension included gestational diabetes. Childhood anthropometric factors associated with high SBP included BMI>85%ile, waist circumference >90%ile, triceps skinfold >85%ile and weight gain velocity between 18 months to 6-7 years. Limitations of this analysis include lack of a term control group and lack of blood pressure measurements at ages prior to 6-7 years of age. For providers, this study highlights the high frequency of high SBP and hypertension in former EPT infants, that may necessitate the need for closer surveillance and management.

Click to read the study published today in Pediatrics

Relevant Reading: Systematic review and meta-analysis of preterm birth and later systolic blood pressure

In-Depth [prospective cohort]: The final analysis of this prospective study included 379 children of an original cohort of 498. The primary outcomes were high SBP and hypertension at 6 to 7 years of age in EPT infants. Secondary outcomes included the association between maternal risk factors, anthropometric outcomes at 6-7 years old and abnormal blood pressures. Of all children with follow-up, 20.6% had high SBP and 10.8% had hypertension. For maternal risk factors, EPT infants born to mothers with maternal gestational diabetes had a greater percent of high SBP and/or hypertension compared to those whose mothers did not (12% vs. 5%, p = 0.02). Children with high SBP were more likely to have BMIs ≥ 85 (34% vs 20%, p = 0.008), have a waist circumference >90%ile (19% vs. 5%, p < 0.001), have triceps skinfold >85%ile (34% vs. 16%, p < 0.001). In regression models for the total cohort, only gestational diabetes (RR = 1.67; 95%CI: 1.04-2.67) and weight gain velocity between 18 months to 6-7 years (RR = 1.28; 95%CI: 1.06-1.53) predicted high SBP or diastolic blood pressure.

Image: PD

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