Abstract
Objective
To develop and validate an instrument to assess adherence to each individual drug taken by patients undergoing long-term treatment.
Design Multicentre prospective observational validation study.
Setting Six general practitioners' clinics and 6 university hospitals in Paris, France.
Participants Patients 18 years and older receiving at least one long-term treatment.
Methods
The instrument was developed from a literature search and interviews with experts. Clarity and wording were assessed during pilot testing with 51 patients. The tool was validated in a sample of consecutive patients. We assessed agreement between adherence measured with our tool and drug diaries and compared measurements from our instrument with (1) the Lu instrument; (2) the Adherence Estimator (AE); (3) patient's adherence assessed by physicians; (4) the Morisky Medication Adherence Scale-4 items (MMAS-4); and (5) the Treatment Burden Questionnaire (TBQ). Reliability was assessed by a test–retest method.
Results
A total of 243 patients taking 961 drugs were recruited in 2014. We found good agreement between adherence measured by our tool and drug diaries (intraclass correlation coefficient (ICC) 0.69, 95% CI 0.34 to 0.91) and a linear relationship between measurement with our tool and (1) the Lu instrument (p<0.01); (2) 2 items of the AE (perceived need for medication (p<0.01) and concerns about medication (p<0.01)); (3) patients' adherence assessed by their physicians (p<0.01); (4) the MMAS-4 (p<0.01) and (5) the TBQ (p<0.01). Reliability of the retest was good (ICC 0.67, 95% CI 0.42 to 0.85).
Conclusions
We developed an instrument with acceptable validity and reliability to assess adherence for each drug taken by patients, usable in hospital and primary care settings.
Citation: Stéphanie Sidorkiewicz, Viet-Thi Tran, Cécile Cousyn Development and validation of an instrument to assess treatment adherence for each individual drug taken by a patient BMJ Open 2016;6:e010510 doi:10.1136/bmjopen-2015-010510
Received: 10 November 2015 Revised: 3 February 2016 Accepted: 5 February 2016 Published: 10 May 2016
Copyright: This is an Open Access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Acknowledgments
The authors thank Caroline Barnes and Cathia Zak for help with questionnaire translation and Laura Smales for reviewing the manuscript before submission. They are particularly indebted to Gerard Reach, Jean-François Bergmann, Virginie Savoldelli and Fabienne Marcellin for sharing their time and expertise during meetings.
