Follow-up Study of a Randomized Controlled Trial of Postnatal Dexamethasone Therapy in Very Low Birth Weight Infants: Effects on Pulmonary Outcomes at Age 8 to 11 Years

Objective

To determine whether postnatal dexamethasone (DEX) exposure affects pulmonary outcomes at school age in children born with very low birth weight (VLBW).

Study design

Follow-up study of 68 VLBW children who participated in a randomized controlled trial of postnatal DEX. Pulmonary function was assessed by spirometry. Current asthma status was obtained from a parent.

Results

Sixty-eight percent of the placebo group had below-normal forced expiratory volume in 1 second (FEV₁), compared with 40% of the DEX group (χ² = 4.84; P = .03), with trends for lower forced vital capacity (FVC) and FEV₁ values in the placebo group. Fifty percent of the placebo group and 34% of DEX group had below normal FEV₁/FVC (χ² =1.59; P =.21). Parent-reported prevalence of asthma did not differ between groups. Logistic regression analysis suggested that the positive effects of DEX on pulmonary function at follow-up were mediated in part by shortened exposure to mechanical ventilation.

Conclusions

Postnatal DEX exposure was associated with higher expiratory flow with no adverse effects on pulmonary outcomes at school age. The prevalences of asthma and impaired pulmonary function underscore the influence of neonatal illness on health at school age, and stress the importance of repeated follow-up examinations of these children.

Abbreviations: BMI, Body mass index, BPD, Bronchopulmonary dysplasia, CI, Confidence interval, CLD, Chronic lung disease, DEX, Dexamethasone, D_LCO, Carbon monoxide diffusing capacity, FEF_25-75, Forced expiratory flow between 25% and 75% of forced vital capacity, FEV₁, Forced expiratory volume in 1 second, FVC, Forced vital capacity, OR, Odds ratio, PFT, Pulmonary function testing, RV, Residual volume, SGA, Small for gestational age, TLC, Total lung capacity, VLBW, Very low birth weight