Doctor: Stéphanie Sidorkiewicz

Title: Medication adherence among patients taking long-term treatments

Supervisor: Philippe Ravaud

Doctoral school: ED 393 Epidemiology and Biomedical Information Sciences, Université Paris Cité

Date of thesis defense: 27/11/2017

Jury: Sylvie Bastuji-Garin, Olivier Saint-Lary, Dominique Costagliola, Gérard Reach, Philippe Ravaud


Against the backdrop of population ageing and medical progress, the prevalence of long-term disorders is rising worldwide. As a consequence, an increasing number of patients need to take medications daily. Medication adherence, which can be defined as the extent to which patients’ medication-taking behaviors coincides with medical prescriptions, may become ever harder to achieve. Non-adherence is a main challenge for physicians and for researchers, especially given its complexity and its dynamic evolution over time.

First, we developed a new instrument to assess medication adherence to each individual medication taken by patients undergoing long-term treatment, taking into account different types of medication-taking behavior. We assessed the instrument’s validity and reliability among 243 outpatients and inpatients taking 961 medications, in France.

Second, we focused on the discordance between medication adherence as reported by patients and drug importance as reported by their physicians. We compared the opinions of 128 patients and physicians and showed that some drugs considered important by the physicians were not correctly taken by patients, a situation that may lead to potential severe consequences. On the contrary, some drugs considered less important by physicians were correctly taken by physicians, which may lead to potential overprescription and avoidable burden of treatment.

Third, we used a crowd sourcing approach to assess physicians’ estimation of the threshold for unacceptable risk of non-adherence, for two distinct types of behavior (episodic missing doses and drug holidays) for the most prescribed drugs in France. Physicians’ estimations varied considerably according to the drugs assessed, suggesting that according to physicians, some drugs are “more forgiving” than others.

Our findings confirm that medication adherence is a complex phenomenon that should not be simply dichotomized into « good adherence » and « bad adherence ». Future work will consist in developing and validating a new online tool inspired from our first study. We will try to sharpen our understanding of the results in our third study by comparing physicians’ estimations to patients’ adherence data. Future interventions are still needed to improve patient-physician discussion about medications in order to reach an “optimal adherence” rather than a “perfect adherence”, taking into account patients’ perspectives.

Link to download the thesis (written in French)


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