P0768 - The effect of postnatal glucocorticoids on renal function and blood pressure in very low birth weight infants

Background: Steroids play a major role during prenatal and postnatal renal development and function. Many neonates require postnatal steroids to treat hypotension, severe respiratory distress and prevention and treatment of bronchopulmonary dysplasia. Steroids are highly potent drugs with known adverse effects on infant growth and lead to poor neurodevelopmental outcomes. We investigated the role of cumulative dose and duration of steroid use on renal function and blood pressure in VLBW infants.

Methods: In a retrospective cohort study, medical records of all VLBW infants (Gestational Age ≤ 35 weeks, birthweight ≤ 1500 grams) admitted to a tertiary care NICU between January 2015 and January 2019 were reviewed for infant demographics, clinical characteristics and use of steroids as well as the blood pressure and creatinine at time of discharge from the NICU. Hypertension was defined as blood pressure greater than 95th percentile and severe hypertension as a blood pressure higher than 99th percentiles for corrected gestational age at time of discharge from the NICU. Pulse pressure and creatinine clearance were calculated at time of discharge.

Results: During the study period, 389 babies were born of whom 283 neonates met inclusion criteria with average gestational age (28 ± 3 weeks) and birthweight (1060 ± 381 grams). Among all patients, 21% (60/283) developed hypertension and 10% (27/283) developed severe hypertension at time of discharge from the NICU. Among infants who received postnatal steroids, 28% (33/116) developed hypertension versus 16% (27/167) of controls (Odds ratio = 2.1, p = 0.011). Similarly, among patients who received postnatal steroids, 15% (17/116) developed severe hypertension versus 6% (10/167) of controls (Odds ratio = 2.7, p = 0.018). There was no statistically significant impact on diastolic or mean arterial blood pressure between the two groups. Cumulative dose of postnatal steroids significantly correlated with systolic blood pressure (R2 = 0.0461, p < 0.001). There was a significant association between cumulative dose of postnatal steroids and pulse pressure (R2 = 0.023, p = 0.005). There was a statistically significant decrease in creatinine with increased steroid dose (R2 = 0.08, p < 0.001) and total steroid days (R2 = 0.097, p < 0.001). With increased steroid dosing and total postnatal steroid days, there was a statistically significant increase in creatinine clearance at time of discharge (R2 = 0.13, p < 0.001; R2 = 0.13, p < 0.001, respectively).

Conclusion: The cumulative dose of postnatal steroids along with the duration of use are associated with an increase in systolic and pulse blood pressure in VLBW infants at time of discharge. Postnatal steroids led to improvement in creatinine clearance during the NICU stay. Thus, postnatal steroids should be used very prudently in VLBW infants to prevent long-term cardiovascular morbidity.