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.
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.
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).
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/
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.