Prospective analysis of ldl-c goal achievement and self-reported medication adherence among statin users in primary care

Background: Improvements in the control of LDL-C levels have occurred in the past decade due to the introduction of increasingly potent statins, such as atorvastatin and rosuvastatin. Many patients, however, do not achieve their LDL-C goals, which presents a practical dilemma for clinicians and highlights the need to identify adherence problems in a clinically relevant manner. Objective: The purpose of this study was to evaluate the relationship between LDL-C goal achievement and both medication adherence and beliefs assessed using structured questioning. Methods: All patients were aged ≥40 years and participated in the cardiovascular risk factor management program STOP-HF (St. Vincent's Screening To Prevent Heart Failure study). One hundred and eighty-five participants who had been prescribed statins, split between those who achieved and those who did not achieve LDL-C goal, were randomly selected for a prospective study examining the relationship between adherence, assessed by the Morisky Medication Adherence Scale (MMAS), and LDL-C goal achievement. Patients' beliefs about medicines were assessed using the Beliefs about Medicines Questionnaire-General (BMQ-G). Main outcome measures were predictors of LDL-C goal achievement and medication adherence and predictors of adherence among patients using the MMAS. Results: The average age of the selected patients was 64.9 (9.9) years; 45% were male, 46% had hypertension, 17.5% had coronary artery disease, and 10% had diabetes. Questionnaires were answered by 119 patients, 71 of whom (59.7%) were goal achievers. LDL-C goal achievers were more likely to respond to the questionnaires than nonachievers (76.8% vs 52.7%; P = 0.002). Fifty-eight respondents (48.7%) reported that they were not fully adherent to medication and in multivariable analysis were twice as likely to miss LDL-C goal compared with those who were adherent. Approximately 25% of patients who reported nonadherence were intentionally so. Patients' beliefs about medicines were a significant predictor of self-reported adherence but not of LDL-C goal achievement. Conclusions: Medication nonadherence may be responsible for failure to achieve goal in many patients who are prescribed statins. In routine clinical care, the structured MMAS questionnaire may provide clinicians with an effective tool to assess medication nonadherence in the context of statin therapy failure. STOP-HF ClinicalTrials.gov identifier: NCT00921960.