Objective airway monitoring improves asthma control in the cold and flu season: a cluster randomized trial

Abstract

Background: The goals of asthma care are reductions in risk and impairment, but achieving these goals requires collaborative work between patients and their clinicians. The purpose of this study was to improve inhaled corticosteroid (ICS) adherence and asthma control by cueing therapeutic communication between patients with asthma and their primary care clinicians.

Methods: We conducted a prospective, cluster-randomized, controlled effectiveness trial to assess the effect of providing visually standardized, interpreted peak flow graphs (CUE intervention) to patients and their clinicians on ICS adherence and asthma control. Asthma control outcomes were analyzed by season to account for seasonal variations in exacerbation frequency.

Results: Although mean log-transformed ICS adherence was not significantly different between the two groups, there was a trend toward preserved adherence in the intervention group over time (P = .16). Intervention patients required fewer courses of oral steroids during winter (9% vs 23%, P < .001) and spring (3% and 17%, P < .001) compared with control subjects. Intervention patients also had fewer periods of worsening symptoms (65% vs 89%, P < .001) and fewer urgent care visits (10% vs 23%, P < .001) during winter compared with control subjects. Post hoc analysis showed significant improvement in the intervention group with respect to ICS adherence during winter months (P < .05), the likely explanation for the reduction in prednisone use and symptoms. Day-to-day peak flow variability in the intervention group fell consistently throughout the study from an average of 32% at baseline to 23% at final measurement (P < .001), indicating less airway reactivity over time.

Conclusions: Our findings provide evidence of the value of peak flow monitoring for patients with asthma during seasons of greatest vulnerability, the cold/flu season. The peak flow information apparently led to improvements in ICS adherence resulting in less need for prednisone rescue and fewer episodes of worsening symptoms.

Trial registration: ClinicalTrials.gov NCT00201188.

Figure 1.

Patient enrollment and assignment.

Figure 2.

Peak flow graph interpretation sheet.

Figure 3.

Sample peak flow trend. PEF = peak expiratory flow.

Figure 4.

Asthma control outcomes by season. A, Prednisone use. B, Worsening symptoms. C, Urgent care utilization. D, Primary care utilization.

Figure 5.

Intervention group peak flow variability.