Adherence with a Hand-Held Electronic Device versus Conventional Peak Expiratory Flow Rate Monitoring in Children with Asthma

Peak flow monitoring is recommended by the National Heart, Lung and Blood Institute once daily for patients with moderate to severe persistent asthma. Previous studies have shown suboptimal adherence to peak flow monitoring and therefore the utility of peak flows has been questioned. Our objective was to perform a prospective study examining adherence of pediatric patients to peak expiratory flow rate (PEFR) monitoring with a device that measures peak flow and forced expiratory volume in 1 second (FEV1) at home (AirWatch®, (iMetrikus, Inc., Carlsbad, CA) versus standard peak flow monitoring (ASSESS® peak flow meter, Respironics, Cedar Grove, NJ) and to determine if home FEV1 monitoring offered an advantage over peak flow. Thirty-nine patients, age 6 to 17 years with moderate to severe persistent asthma were enrolled in an 8-month crossover study. The study consisted of four phases: a 2-month phase 1 to assess compliance; 4-month long crossover phases 2 and 3 when patients used either ASSESS® or AirWatch®, and a 2-month phase 4 when all patients used AirWatch®. Patients who were compliant with AirWatch® and PEFR recording during phase 1 were randomized to either AirWatch® or daily ASSESS® peak flow. Patients sent AirWatch® data by modem at least once per month. Assess® data was collected on a monthly basis from the patient’s diary. Patients using AirWatch® performed at least one peak flow approximately 77% of the days during the study period. Patients using ASSESS® reported that they performed one or more peak flows on 93% of the days. AirWatch® predicted exacerbations of asthma 55% of the time versus ASSESS® 50% of episodes. Most patients (87.5%) preferred AirWatch®. Overall adherence with once daily peak flows occurred over 75% of the time for patients using either device. There was no difference between standard ASSESS® peak flow meter and AirWatch® in predicting exacerbations, although most patients preferred AirWatch®. (Pediatr Asthma Allergy Immunol 2006; 19[2]:118–125.)