Relationship between adherence, atopic status and symptom control
In order to determine whether change in symptom control with ICS treatment was related to objective biomarkers that determine steroid responsiveness, we assessed adherence and TRACK score at baseline and follow-up in atopic and non-atopic wheezers separately. Overall adherence was similar in atopic and non-atopic children (Table 3). There was a significant and clinically meaningful increase (TRACK increase of >10) in symptom score only in atopic wheezers from baseline to follow-up (Table 3 & Fig 2A), while TRACK remained similar in non-atopic wheezers (Fig 2B). When all atopic wheezers were divided into those with moderate or good adherence (> 60%), compared to those with poor adherence (<60%), only atopic wheezers with adherence > 60% had a significant increase in TRACK score from baseline to follow-up visits (Fig 3). This suggests symptom control and ICS adherence are only positively related in the sub-group of wheezers who have a steroid responsive phenotype.