Respiratory Outcomes Stratified by ICS Therapy
Respiratory outcomes that were assessed, included having a diagnosis of asthma as well as acute care use before and after the first pulmonary clinic visit under the assumption that subjects receiving ICS therapy were all prescribed it by the conclusion of their pulmonary visit. In terms of acute care usage prior to the first pulmonary visit, subjects initiated on ICS therapy as outpatients had more absolute numbers of emergency department (ED) visits (p <0.001) and hospital admissions (p <0.001) than those on ICS therapy at NICU discharge or not started at all (Supplemental Table 3 ). There were no differences in acute care usage after first pulmonary clinic visit between the three groups.
The frequency of asthma diagnosis (73.4%) in those initiated on ICS therapy as outpatients was much higher than in those on ICS therapy at NICU discharge (51.9%) or not initiated at all (36.4%;p <0.001). However, given that differences in the age at the time of first pulmonary clinic visit existed (p <0.001), as well as duration of follow-up time (p =0.001) between the three groups, we also performed adjusted logistic regression to account for these differences and to adjust for potential confounders related to prematurity. Adjusted logistic regression revealed that children started on an ICS at any point as an outpatient had a higher likelihood of an ED visit (2.68±0.70;p <0.001) and/or rehospitalization (4.81±1.16;p <0.001) prior to their first outpatient pulmonary visit compared to children never on an ICS (Table 4 ). After any time following the first pulmonary visit, the likelihood of ED visits and re-hospitalizations for those started on ICS therapy as an outpatient, dropped to 1.73±0.35 (p =0.007) and 1.78±0.37 (p =0.006), respectively, when compared to children never on an ICS. There were no differences in the likelihood of ED visits or rehospitalizations between those on ICS therapy at NICU discharge versus those never on an ICS.
The likelihood of a diagnosis of asthma was higher in both children started on an ICS as an outpatient (3.58±0.84; p <0.001) and those prescribed an ICS continuously since NICU discharge (1.97±0.65; p =0.040) compared to those never on an ICS. Additionally, of those diagnosed with asthma in the outpatient setting, the time until asthma diagnosis was earliest in the children started on an ICS as an outpatient (p <0.001) (Figure 1 ).