Table 1 compares the feedback and control groups with respect to demographic variables, respiratory illness, lung function, and smoking status at 4 months. The two groups were similar with regard to most of these characteristics with the following exceptions. Significantly more feedback participants than control participants were nonsmokers at 4 months (p = 0.04). Baseline lung function was marginally worse in the control group (p = 0.05). In addition, a substantially larger proportion of control subjects demonstrated a significant acute respojnse at baseline to bronchodilator therapy (isoproterenol) as indicated by 10 percent or more improvement in FEVi within 10 min after inhalation of the bronchodilator (p<0.0001).
Table 2 compares the feedback and control groups on the measures of adherence derived from the NC at the first 4-month follow-up. Between-center differences were not significant; therefore, the data are pooled. Compared with the control group, the feedback group averaged significantly closer adherence to the prescribed three inhaler uses per day (1.95 ±0.68 [SD] vs 1.63 ±0.82 sets per day [p = 0.003]). The feedback group averaged 23 percent more sets per day than the control group. In addition, significantly more feedback group participants averaged two or more sets per day compared with the control group (p = 0.0003).

Table 1—Demographic and Baseline Variables and Four-Month Smoking Status: Feedback vs Control Groups

Table 2—Comparison of Feedback and Control Groups on Measures of Inhaler Adherence