Tools to Assess Medication Adherence

The issue of medication adherence (MA) has long been undestimated but is now growing interest due to both the increase of patients with chronic diseases and the aging of the population. According to the World Health Organization, only 50% of patients with chronic illnesses correctly follow physician's prescriptions in developed countries. Beyond the individual consequences that failure to adherence can engender (increased morbidity, mortality and hospitalizations), this concept also encompasses a collective dimension (risk of transmission of infectious diseases and increased health care costs). Today, improving MA would have more impact on human health than developping new medical therapies. That's why detecting non-adherence constitutes a major public health issue in which pharmacists play a significant role through medication reconciliation and patients' education. The methods wildly used are based on indirect measurement: questionnaires completed by the patient himself or the Medication Possession Ratio (MPR). Each method has its own advantages and disadvantages, but none is considered as the gold standard. The Montpellier University Hospital set up a MA self-report scale ranging from 0 (low) to 10 (high adherence) in the various care units where the clinical pharmacy activity is deployed. The purpose of this study was to assess the MA according to this numerical scale and the MPR calculation, and evaluate the correlation between these two methods.