Exploring the determinants of medication use in patients with chronic conditions

Abstract

Medications are dispensed with the expectation that they will be taken exactly as prescribed. Adherence is therefore a determinant of the effectiveness of treatment and ultimately of the health system. Poor adherence has been shown to have both health and economical negative consequences. This underpins the importance for the exploration of barriers and facilitators to adherence. The individual’s beliefs and behaviours that may be hindering adherence need to be also explored as part of the of patient-centred care approach. These could lead to the implementation of tailored and targeted interventions based on a strong theoretical scaffold, so as to make the intervention more effective. The overall aim of this study was to explore the determinants of medication use in patients suffering from chronic conditions. The study was divided into two phase. The aims of Phase 1 of this study were to systematically review published literature that applied the Theoretical Domains Framework to explore the behavioural determinants which affect prescribed medication adherence in adults patients who are suffering from chronic conditions. The Theoretical Domains Framework (TDF) is a model which allows systematic evaluation and assessment of barriers and enablers that influence behaviour change. It was therefore an appropriate framework to apply whilst studying aspects which affect adherence to medication. The elicited determinants were further investigated in Phase 2 of the study, where a cross-sectional study was carried out amongst community- dwelling adults suffering from chronic conditions. The beliefs about medications and the medication-related burden were assessed using the Beliefs about Medicines Questionnaire (BMQ) and the Living with Medicines Questionnaire (LMQ) v3 respectively. The possible relationship between the beliefs about medicines and the burden of medicine taking was also explored.

First a systematic review was conducted where, in line with the registered protocol (PROSPERO 2017:CRD42017067454), seven electronic major databases, were searched for articles in the English language that explored medication adherence amongst patients (<18 years) using or were mapped to the TDF domains. Studies which included patients of any ethnicity who are at least on one prescribed acute or regular medication were included in the study. Data extraction and quality assessment using a critical appraisal tool were conducted. Out of the 562 titles retrieved, only seven were eligible for review (five qualitative studies and two systematic reviews). Overall, the papers were of good quality but the research design was only of partially good quality. The systematic review has identified the most prevalent behavioural determinants based on the TDF that act as barriers and facilitators to prescribed medication adherence. The TDF domain ‘Beliefs about consequences’ was found to be the most cited facilitator and barrier to adherence in the systematic review. Other determinants that were elicited belonged to the TDF domains 1) Social influence, 2) Knowledge, 3) Beliefs about Capabilities, 4) Behaviour regulation. The cross-sectional study of Maltese residents aged 18 years or older and suffering from chronic illness was carried out on patients in the community. Those meeting the inclusion criteria were invited to participate in the study during an event organised by any of the 68 local councils or community groups around Malta and Gozo. A questionnaire was employed to determine demographics, beliefs about medicines using the Beliefs about Medicines Questionnaire (BMQ) General and Specific and the medicine-related burden were assessed using the Living with Medicines Questionnaire (LMQ) v3 to attendees who accepted to participate. Maltese patients were found to have high medication beliefs in terms of benefit, over use and concerns. Patients with cardiovascular disease had significantly higher medication necessity beliefs but lower harm and concern beliefs. Male patients experienced higher medication-related burden than females. Patients residing in the western region of Malta experienced higher medication related beliefs when compared to those living in the South Eastern Region. Polynomial regression was applied to determine the multidimensional relationship of ‘necessity’ and ‘concerns’ beliefs for medication-related burden. P-values ≤ 0.05 were taken to be significant. Ethics approval for this study has been granted. Confirmatory polynomial regression rejected the differential score model for the data obtained from the cross-sectional study. Exploratory polynomial regression found that quadratic terms indicated the best fitting model for predicting medication-related burden. Medication-related burden was found to be dependent on ‘concerns’ beliefs and increased as the ‘concerns’ beliefs predictor increased. Patients < 65 years old have high concern beliefs and were statistically significant associated with the VAS score. Factors contributing to the Medication-related Burden amongst the Maltese population were related to 1) Relationship with Healthcare Professional about Medicines, 2) Practical Difficulties, 3) Cost-related Burden, 4) Concerns about Medication use, 5)Varying the regimen of the chronic medications. The necessity beliefs of the medication may not influence medication-related burden but concern beliefs are predictive of medication-related burden. Alleviating patients’ concerns can also lower medication-related burden and so enhance medication use. This study supports further the importance of considering the multidimensional characteristics of Necessity-Concerns Framework (NCF) by employing polynomial regression rather than considering the differential score as one variable outcome of two factors: ‘necessity’ and ‘concerns’ beliefs.