How should we measure medication adherence in clinical trials and practice?
Authors Jeannie K Lee, Karen A Grace, Terri G Foster, Monica J Crawley, Goldina I Erowele, et al
Published Date October 2007 Volume 2007:3(4) Pages 685—690
Published 4 October 2007
Jeannie K Lee, Karen A Grace, Terri G Foster, Monica J Crawley, Goldina I Erowele, Hazel J Sun, Phuong T Turner, Lance E Sullenberger, Allen J Taylor
Pharmacy and Cardiology Services, Walter Reed Army Medical Center, Washington, DC, USA
Objective: To determine if simple adherence measures, such as twenty-four hour recall and refill history, are accurate for routine use, compared to more time-consuming measures such as pill counts.
Design: Randomized, double-blind, placebo-controlled trial.
Setting: Walter Reed Army Medical Center, a tertiary medical center in Washington.
Patients: Men and women >30 years old with known coronary heart disease and taking a statin medication.
Intervention: Clinical pharmacists met with patients for adherence assessments.
Main outcome measures: Adherence was measured by pill counts, twenty-four hour recall by patient, and refill history per computer record. Temporal changes in these adherence measures were assessed using general linear models for repeated measures.
Results: Adherence was consistently greater for the experimental agent than for the statin therapy (n = 148). Mean pill count adherence for statin drug was 78.7 ± 25.2% compared to 93.5 ± 11.6% (P < 0.001) for the study agent. Refill history and twenty-four hour recall inaccurately measured adherence when compared to pill counts. Adherence, as determined by pill count, for both experimental (P = 0.029) and statin therapy (P = 0.015) showed significant variability across time in general linear models. Neither refill history nor twenty-four hour recall was sensitive to temporal changes.
Conclusions: Twenty-four hour recall and refill history inaccurately measure medication adherence for both clinical trial and clinical practice pharmacotherapies. Further, these measures are insensitive to changes in adherence. For a single or multiple assessments across time, pill count more accurately measures medication adherence. Pill count should be the standard for monitoring medication adherence for both clinical trials and clinical practice.
Keywords: adherence, hyperlipidemia, niacin, pharmacist, pill count, simvastatin
Readers of this article also read:
Letter to the editor regarding "Study design of 'Friends for Life': a process and effect evaluation of an indicated school-based prevention program": response to Lima et al
Kösters MP, Chinapaw MJ, Zwaanswijk M, van der Wal MF, Koot HM
Published Date: 23 April 2014
Published Date: 16 April 2014
Shrinking the room for invasive mechanical ventilation in acute chronic hypercapnic respiratory failure: yes, but must be sure to have opened windows for noninvasive ventilation
Rodriguez AME, Scala R, Ambrosino N
Published Date: 9 July 2013
Muc-Wierzgoń M, Nowakowska-Zajdel E, Klakla K, Dzięgielewska-Gęsiak S, Fatyga E, Kokot T
Published Date: 3 July 2013
Intervention for improving the appropriateness of physician orders for oral medications in geriatric VIP patients during the journey to JCI accreditation
Zhu LL, Zhou Q
Published Date: 28 May 2013
Tuohy E, Litt E, Alikhan R
Published Date: 20 May 2013
Published Date: 8 March 2012
Schneider EW, Johnson MW
Published Date: 16 September 2011
Sudenga SL, Royse KE, Shrestha S
Published Date: 15 September 2011
Espandar L, Sikder S, Moshirfar M
Published Date: 6 February 2011