Effectiveness of a tailored intervention to improve medication adherence

Adherence to chronic medication is problematic in clinical practice and leads to poor disease control with a burden on patients’ quality of life and health care systems. Research shows that about 50% of patients with a chronic condition are not adherent, with estimates ranging from 17 to 80% adherence. Especially drugs for asymptomatic chronic conditions are found to have low adherence rates. In several studies, non adherence was shown to be highest in the first year after start with chronic medication. Consequently, interventions to warrant good compliance are most efficient at drug initiation.

The multifaceted nature of the adherence problem illustrates that improving adherence is complex and needs interventions tailored to the individual patient. Possible interventions can be distinguished to focus more on perceptual barriers (intentional non-adherence) or on practical barriers (non-intentional non-adherence), with different options for interventions and different involvement of primary health care providers. As at start of therapy the future drug use by prescribing or dispensing patterns is not known, a predictive tool is needed to assign a patient to one of the main intervention lines. Furthermore to implement interventions in primary health care in an effective and efficient way so that they become part of usual care, a good cooperation between pharmacists and technicians on the one hand and General Practitioners (GPs) and practice nurses and assistants on the other hand is needed.

Philips Research and the University of technology in Eindhoven developed the Probabilistic Medication Adherence Scale (ProMAS), which is an 18-item questionnaire to assess actual non-adherence behaviour. In parallel, Philips Research developed the Adherence Control Engine (ACE), a questionnaire with 23 questions that assess the underlying causes of non-adherence. The result of ACE provides insight into perceptual and practical barriers that may hamper a patient’s adherence. Such an insight can support care professionals in selecting the appropriate intervention set. Consequently, in patients starting chronic medication and at high risk for non-adherence as assessed by PROMAS a subsequent ACE outcome could be used to assign them to an intervention strategy to overcome perceptual or practical barriers.
Taken together, this study aims to assess the effectiveness of combined use of ProMAS and ACE in starters with cardiovascular or oral blood glucose lowering medication in improvement of medication adherence. Moreover, since an explicit tailored adherence intervention is not yet implemented in the primary care group context, a second main objective is to develop the implementation strategy such that it can run in a manner acceptable to all stakeholders in the health care collaborative (being pharmacists, general practitioners and patients).

Patients receiving the intervention (testing for risk for non-adherence and offering a tailored intervention based on the patient’s ACE profile when at high risk for non-adherence) will be more adherent compared to patients who will not receive the intervention

baseline measurement and 8-months follow-up

In the pharmacy, the pharmacist will intervene at the moment of the second dispense when an intervention is appropriate. In the intervention pharmacies for patients with a risk for non-adherence, the Adherence Control Engine (ACE) questionnaire will be used as a systematic decision support tool to tailor interventions based on the patient’s ACE profile that identifies potential perceptual (intentional non-adherence) and practical (unintentional non-adherence) barriers. Depending on the nature of the barriers, an intervention strategy is chosen.
All interventions start with a discussion of the ACE results in a manner that makes use of the patient-centered techniques. When perceptual barriers (e.g. concerns, motivational issues, fear of side effects) appear to exist for the specific patient, the pharmacist discusses the relevant issues in the ACE profile using the patient-centered communication techniques and aims to take away or diminish the perceptual barriers. In addition to the conversation, self-assessment of clinical measures will be proposed, since these have been shown to increase medication adherence. When agreed by the patient, these will be initiated in the pharmacy. When practical barriers appear to be the most important barriers for the specific patient, the pharmacist offers one of several practical solutions, e.g. pill organizer, use of a Baxter system, reminders, seek the help of the patient’s social network, simplification of dosage scheme. The pharmacist monitors the result of the intervention.