Improving medication adherence in patients with chronic disease using a targeted and tailored approach

Abstract

Improving adherence to medications is an opportunity that can yield great improvements in health outcomes and reducing health costs. Supporting adherence to medicines requires insight into a patient’s medication-taking behaviour and their reasons for non-adherence. Adherence interventions that show most promise include multifaceted interventions, and those targeted to non-adherent patients and/or tailored to patient-specific reasons for non-adherence. To identify non-adherent patients and their reasons for non-adherence in the practice setting, I argue that we require inexpensive measures that are easy to use and can inform the discussion with patients about their adherence. Adherence scales are inexpensive, easy-to-administer and have the potential to explore both medication-taking behaviour and reasons for behaviour. The overall aim of the thesis is to determine if a targeted and tailored intervention based on a discussion informed by validated adherence scales, will improve adherence to a recently initiated cardiovascular medication. I hypothesise that targeting and tailoring an intervention to non-adherent participants based on a discussion informed by adherence scales, will improve adherence at three months as measured by the four-item Medication Adherence Questionnaire (MAQ). I will also test whether improvements in adherence at three months are sustained at six months and explore the changes in adherence and reasons for non-adherence over time. The first part of the thesis involved identifying validated adherence scales suitable for use in the intervention. A systematic review was conducted on adherence scales to explore their use and validation. We found that adherence scales measured different aspects of adherence: medication-taking behaviour, barriers to adherence and beliefs associated with adherence. Adherence scales have been validated in different disease populations and against different measures of adherence. We selected two adherence scales for our study: the MAQ and Beliefs about Medicines Questionnaire-Specific (BMQ-S). The MAQ is one of the most commonly used adherence scales that has been validated in many disease populations and against different measures of adherence including electronic monitoring. The BMQ-S has been extensively used to elicit medication beliefs associated with medication adherence and validated in a number of diseases including cardiovascular disease, asthma and depression. A randomised controlled trial was conducted to determine if a targeted and tailored intervention would improve medication adherence. Four hundred and eight patients were assessed for eligibility from two community pharmacies, from which 152 patients were enrolled into the study. All enrolled participants completed the MAQ, BMQ-S and Brief Illness Perceptions Questionnaire (BIPQ). There were 120 participants identified as non-adherent using the MAQ, who were randomised into an intervention or control group. The remaining 32 participants were identified as adherent. In the intervention group, the results from the MAQ, BMQ-S, and BIPQ were used by the researcher (TN) to identify reasons for non-adherence and inform the implementation of a tailored strategy. There was no difference between the mean MAQ scores at baseline: 1.58 ± 0.79 (intervention) and 1.60 ± 0.67 (control) (p=0.9008). At three months, the mean MAQ score in the intervention group was significantly lower than the control group, reflecting an improvement in adherence (mean MAQ 0.42 ± 0.59 v 1.58 ± 0.65; p<0.001). The significant improvement in the mean MAQ score in the intervention group compared to control was sustained at six months (0.48 ± 0.68 vs 1.48 ± 0.83; p<0.001). The intervention consisted of an interview and the implementation of a tailored strategy. The participant’s reasons for non-adherence were explored using their responses to the MAQ, BMQ-S and BIPQ. Where possible the researcher used responses to the adherence scales to inform further discussion regarding the participant’s adherence and the factors that supported or impeded them taking their medicine. The researcher and participant then selected and implemented an evidence-based tailored strategy to support the participant’s adherence based on the information discussed in the interview. Tailored strategies included reminders, cognitive-educational strategies, both a reminder and cognitive-educational strategy, behavioural-counselling and social support. For example, if the main barrier to adherence is identified as forgetfulness, then the participant will receive a reminder strategy. Changes in the responses to the questionnaires were explored in the adherent, intervention and control groups, and also within the different types of strategies. In the intervention group, patients who received a cognitive-educational strategy had improved perceived understanding of their illness corresponding to improvements in their adherence score on the MAQ. As expected, patients who received a reminder strategy on its own had no significant changes in their beliefs about medicines and illness perceptions. An intervention that targeted non-adherent participants and tailored to the participant-specific reasons for non-adherence was successful at improving medication adherence. Better understanding how a patient’s adherence and beliefs about their medicines change over time, will inform improved interventions to support adherence. This intervention was quick and easy to administer and has the potential for clinical implementation if proven successful in larger studies that assess clinical outcomes.