Antihypertensive drug exposure in premature infants from 1997 to 2013

BACKGROUND: Systemic hypertension is increasingly recognised in premature infants. There is limited evidence regarding treatment, and most published treatment recommendations are based solely on expert opinions. METHODS: We identified all infants born ⩽32 weeks of gestation and ⩽1500 g birth weight discharged from one of 348 neonatal ICUs managed by the Pediatrix Medical Group between 1997 and 2013. We defined antihypertensive drugs as vasodilators, angiotensin-converting enzyme inhibitors, β receptor blockers, calcium channel blockers, and central α2 receptor agonists. We compared characteristics between infants who were treated with at least one antihypertensive drug during their initial hospitalisation and infants who were not prescribed antihypertensive drugs using Wilcoxon's ranked sum test or Pearson's χ2-test. RESULTS: We identified 2504/119,360 (2.1%) infants who required at least one antihypertensive drug. The median postnatal age of first exposure was 48 days (25th, 75th percentile 15, 86), and the median length of therapy was 6 days (1, 16). Hydralazine was the most commonly prescribed antihypertensive with 1280/2504 (51.1%) treated infants exposed to the drug. More than two antihypertensive drugs were administered in 582/2504 (23.2%) infants, and 199/2097 (9.5%) of the treated infants were discharged home on antihypertensive therapy. Infants who received antihypertensive drugs were of lower gestational age (p<0.001) and birth weight (p<0.001) compared with infants not prescribed antihypertensive drugs. CONCLUSIONS: Our study is the largest to describe current antihypertensive drug exposure in a cohort of exclusively premature infants born ⩽32 weeks of gestation. We found wide variations in practice for treating hypertension in premature infants.