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Introduction: Calculating patients’ medication availability from dispensing or refill data is a common method to estimate adherence. The most often used measures, such as the medication possession ratio (MPR), average medication supplies over an arbitrary period. Averaging masks the variability of refill behavior over time. Goal: To derive a new absolute adherence estimate from dispensing data. Method: Dispensing histories of patients with 19 refills of direct oral anticoagulants (DOAC) between 1 January 2008 and 31 December 2017 were extracted from 39 community pharmacies in Switzerland. The difference between the calculated and effective refill day (ΔT) was determined for each refill event. We graphed ΔT and its dichotomized version (dΔT) against the MPR, calculated mean ΔT and mean dΔT per refill, and applied cluster analysis. Results: We characterized 2204 refill events from 116 DOAC patients. MPR was high (0.975 ± 0.129) and showed a positive correlation with mean ΔT. Refills occurred on average 17.8 ± 27.9 days “too early”, with a mean of 75.8 ± 20.2 refills being “on time”. Four refill behavior patterns were identified including constant gaps within or at the end of the observation period, which were critical. Conclusion: We introduce a new absolute adherence estimate ΔT that characterizes every refill event and shows that the refill behavior of DOAC patients is dynamic.

Background: Therapy with oral anticoagulation (OAC) can be challenging, especially in high risk groups such as chronic patients. Gaps in patient knowledge about OAC are linked to reduced effectiveness and safety of treatment. The objectives of this study were i) to assess OAC knowledge gathered during an intermediate medication review (MR) in patients taking vitamin K antagonists (VKA) or non-vitamin K antagonist oral anticoagulants (NOAC); ii) to assess OAC knowledge two weeks after the MR, and iii) to evaluate patient satisfaction with the MR service in community pharmacies. Methods: Chronic OAC patients were invited for a regular MR service in Swiss community pharmacies, the so-called “Polymedication-Check” (PMC). OAC knowledge was assessed with seven newly generated items asked face-to-face during a PMC and by telephone two weeks later. Knowledge gaps, pharmacists’ spontaneous interventions, and patient satisfaction were documented by observing pharmacy students. Treatment groups were compared. Results: Of all patients (n = 81), the number of patients with one or more knowledge gaps decreased from 66% to 31.3% after PMC (p < 0.001). NOAC patients (n = 31) had more knowledge gaps than VKA patients (n = 50; p < 0.05). Most patients (98.6%) were satisfied with the counselling provided by the pharmacists. Conclusion: The majority of chronic OAC patients shows knowledge gaps. Although spontaneous, the provision of tailored education during a PMC increased patient OAC knowledge.

Several methods exist for measuring medication adherence. The Time4MedTM device (Adherence Innovations, Hong Kong) is a small, electronic card to affix on medication packaging that records date and time of intakes when a button is pushed. We aimed to validate the device with an emphasis on polypharmacy. Twenty volunteers used Time4MedTM devices with a virtual thrice daily intake over 14 days. Diary-recorded date and time were compared to electronically-stored events. Functionality, reliability and recovery for different stress conditions were calculated. User‘s acceptability was assessed with the System Usability Scale (SUS). Eleven elderly outpatients (mean age 80.2 ± 8.1 years) taking >3 medications daily used the device over 4 weeks. Volunteers logged 847 events. Functionality (100%), sensitivity (94.9%), specificity (99.4%) and recovery (100%) were high. Dropping the smart card and storing it in a refrigerator caused either the recording of false events or no recording at all. The mean SUS score was 82.6 (SD 14.8), demonstrating excellent acceptability. Satisfaction was very high for volunteers and patients, except for pushing the button. Time4MedTM devices are highly accurate in recording, retaining and delivering electronic data of multiple medication intake. They are well accepted by elderly patients. They can be recommended in clinical studies and for practitioners who desire to elucidate adherence patterns of ambulatory patients.