Objective adherence to inhaled therapy by patients with COPD has not been reported. The aim of this study was to objectively quantify adherence to preventer DiskusTM inhaler therapy by patients with COPD with an electronic audio recording device (INCATM). This was a prospective observational study. On discharge from hospital patients were given a salmeterol/fluticasone inhaler with an INCATM device attached. Analysis of this audio quantified the frequency and proficiency of inhaler use. COPD patients (n=265) were recruited. The mean age 71 years, mean Forced Expiratory Volume in 1-second 1.3 Litres, and 80% had evidence of mild/moderate cognitive impairment. By combining time of use, interval between doses and critical technique errors, thus incorporating both intentional and unintentional non-adherence, a measure "Actual Adherence" was calculated. Mean Actual Adherence was 22.9% of that expected if the doses were taken correctly and on time. Seven percent had an Actual Adherence>80%. Hierarchical clustering found three equally sized well-separated clusters corresponding to distinct patterns: Cluster 1 (34%) had low inhaler use and high error rates, Cluster 2 (31%) had high inhaler use and high error rates, and Cluster 3 (30%) had overall good adherence. Lung function and co-morbidities were predictive of poor technique, while age and cognition with poor lung function distinguished those with poor adherence and frequent errors in technique. These data may inform clinicians both in understanding why a prescribed inhaler is not effective and to devise strategies to promote adherence in COPD.
Royal College of Surgeons in Ireland ->