The INCA^TM (Inhaler Compliance Assessment^TM): A comparison with established measures of adherence^†

^†Research conducted in Beaumont Hospital, Royal College of Surgeons in Ireland, Dublin, Ireland.

Abstract

Objective: To compare the Inhaler Compliance Assessment^TM (INCA^TM), a novel audio-recording device objectively measuring timing and proficiency of inhaler use, against established adherence measures, and explore its discriminant and predictive validity.

Design: Prospective observational study; 184 chronic obstructive pulmonary disease (COPD) patients used an INCA^TM-enabled salmeterol/fluticasone inhaler for one-month post-hospital discharge.

Main outcome measures: INCA^TM (Attempted, Attempted Interval, Actual) adherence correlated with Doses Used Rate, self-reported adherence and prescription refill for concurrent validity. Discriminant validity for reason for admission, cognition and lung function; predictive validity for health status and quality-of-life.

Results: Rates of Attempted, Attempted Interval and Actual adherence were 59, 47 and 23%, respectively. Only 7% of participants had Actual adherence >80%. INCA^TM variables significantly correlated with Doses Used Rate but not with self-report; Attempted and Attempted Interval were weakly associated with prescription refill. Higher cognitive and lung functioning groups had better INCA^TM adherence. Attempted and Attempted Interval predicted health status, while Doses Used Rate predicted quality-of-life.

Conclusion: INCA^TM did not strongly correlate with self-report or prescription refill data. Discriminant and predictive validity demonstrated by INCA^TM suggests the potential utility of the INCA^TM as a method to identify intentional and unintentional adherence to inhaled medication and facilitate targeted intervention.

Keywords:

• chronic obstructive pulmonary disease (COPD)
• adherence
• inhaler
• electronic monitor
• construct validity
• predictive validity

View correction statement:

Corrigendum

Acknowledgements

This project is a research-initiated study supported by the Royal College of Surgeons in Ireland Research Institute [grant number 1855] and hosted in Beaumont Hospital, Royal College of Surgeons in Ireland, Dublin, Ireland. The INCA^TM device was manufactured and supplied by Vitalograph, Ennis, Ireland and the salmeterol/fluticasone Diskus^TM inhalers were provided by GlaxoSmithKline. The authors’ responsibilities were as follows: LM, FD, GM and RWC designed the research; RBR and RWC developed the electronic engineering and signal processing methodology; IS & RWC developed the INCA^TM adherence calculation methods; LM, FD, IS, GG and RWC advised on the statistical analysis; CM was primarily involved in patient recruitment, data collection and data analysis; KB retrieved the prescription refill data and calculated MPR and PDC variables; CM and LM wrote the manuscript; LM had primary responsibility for the final content. All co-authors edited and approved this manuscript. We would like to extend our sincerest gratitude to all participants for contributing their time and effort, and also to the staff of Beaumont hospital for their support in facilitating this research.

Notes

^† Research conducted in Beaumont Hospital, Royal College of Surgeons in Ireland, Dublin, Ireland.

This article was originally published with errors. This version has been amended. Please see Corrigendum (http://dx.doi.org/10.1080/08870446.2017.1352219)