Non-adherence to lipid-lowering therapies: a need for more studies to evaluate reasons for medication non-adherence

Abstract

Linked Comment: Refiker. Int J Clin Pract 2011; 65: 1321. To the Editor: The letter by Ege et al. (1) has highlighted some of the factors associated with suboptimal adherence to lipid-lowering therapies as found in our recent study (2). Admittedly, although these factors were evaluated from a relatively large Chinese population, their generalisability to other patient groups requires caution as medication adherence is affected by health beliefs and cultural-specific attitudes, as well as its therapeutic-specific features like dosage, frequency and side effect profiles. The use of statins in clinical practice is strongly supported by a substantial body of evidence. A recent review of statin trials has established the efficacy and safety of statins in primary prevention across a wide range of high-risk patients (3). In secondary prevention trials, intensive therapy was shown to be safe and could offer further clinical benefits including reduction in cardiovascular risk and hospitalisation for heart failure patients, as well as clinical events in patients with acute coronary syndrome (3). In clinical practice, physicians play an important role to reduce the impact brought forth by dyslipidaemia. Family physicians are influential on its control – this has been impressively demonstrated by a recent study in a US, community-based, independent family medicine practice, where statin therapeutic substitution could be successfully performed within the context of its typical patient care (4). In addition, there is a modelled annual cost savings associated with medication switching. This shows that changes in the model of care of the healthcare system on drug adherence could positively influence clinical outcomes. However, there are simply so many factors influencing patient adherence and there are still a scarcity of studies evaluating the impact of these factors. Retrospective studies conducted on large database (1) are unlikely to explore the underlying reasons of statin non-adherence. One must bear in mind that medication adherence is affected by: (i) demographic variables like age, gender, race, socioeconomic status, educational levels and areas of residence, (ii) Clinical factors like patients’ knowledge on medications, beliefs about treatment, self-efficacy, the presence of cognitive impairment, the presence of comorbidities, smoking and drinking, (iii) drug-related factors like complexity of medication regimen, adverse drug reactions, initial medication dose, mono- vs. combination therapy and (iv) Physician factors like single vs. multiple medical provider; patient–clinician relationship; shared decision-making approach between physicians and patients on the initiation of drugs and their continuation (5). Nevertheless, more studies on the adherence profiles and identification of the most influential factors leading to poor adherence in different clinic settings among different patient groups are earnestly needed. As one can hardly search a comprehensive list of reasons why patients prescribed lipid-lowering therapies are not medication-adherent, evaluation of the reasons of medication non-adherence in patients of different backgrounds represents an important future research direction. The authors have no conflicts of interests to declare.