Self-Reported Adherence to Cholesterol-Lowering Medication in Patients with Familial Hypercholesterolaemia: The Role of Illness Perceptions

Abstract

The objectives of this study are to describe levels of adherence to cholesterol-lowering medication and to identify predictors of adherence in patients with familial hypercholesterolaemia (FH). Descriptive questionnaire study. 336 adults patients with FH attending one of five outpatient lipid clinics in South East England underwent a clinical assessment by a nurse and completed a questionnaire. The questionnaire assessed self-reported adherence to cholesterol-lowering medication, anxiety, depression, and patient perceptions of heart disease. Overall, participants reported high levels of medication adherence, although 63% reported some level of non-adherence. Total medication adherence (never deviating from the regimen) was more likely to be reported by older participants, those with no formal educational qualifications, those with a personal history of cardiovascular disease, those with a lower total cholesterol level, and those with a greater difference between untreated cholesterol levels and current cholesterol levels. The illness perceptions associated with reported total adherence were lower perceived risk of raised cholesterol, perceiving greater control over FH, and perceiving genes and cholesterol to be important determinants of a heart attack. Emotional state was not associated with medication adherence. In logistic regression analysis, predictors of total medication adherence were having personal history of cardiovascular disease, having no formal qualifications, and perceiving genes to be important determinants of a heart attack. Both clinical factors and patients' illness perceptions were associated with self-reported cholesterol-lowering medication adherence. The association with illness perceptions was small and many of these associations may be a consequence, rather than a cause, of greater adherence. Given this, intervention strategies aimed at helping patients' to establish routines for medication taking may be more effective in increasing adherence than interventions designed to alter perceptions related to taking statins.