MEASURING ADHERENCE WITH THERAPY FOR CHRONIC DISEASES - IMPLICATIONS FOR THE TREATMENT OF HETEROZYGOUS FAMILIAL HYPERCHOLESTEROLEMIA

The failure of patients to adhere adequately to prescribed medication and behavioral regimens is an important medical problem. Poor adherence is most common when the treatment regimen is preventive rather than curative, when patients are asymptomatic, and when the duration of treatment is long. For these reasons, adherence with dietary therapy for hypercholesterolemia is well recognized to be a significant clinical and research challenge. Medication adherence has been acknowledged to be a problem for those treatments with significant side effects, such as flushing and pruritus or the low palatability of bile acid sequestering agents. The availability of drugs that lack these effects has long been viewed as an important contribution to improving overall patient compliance. However, the literature on patient adherence with life-long treatment regimens that are simple and palatable (e.g., antihypertensives) suggests that while these improved treatments can enhance adherence, the overall rates of patient compliance still average only 50%. The fact that patients with heterozygous familial hypercholesterolemia are at high risk for early coronary artery disease and death if they fail to adhere to therapy is not sufficient to assure high rates of appropriate therapy over long periods of time, as demonstrated by the poor or erratic adherence commonly reported to treatments for other life-threatening diseases, such as advanced renal disease, hemophilia, and type I diabetes. The measurement of patient adherence to hypercholesterolemia therapy is often neglected in clinical practice and inadequate in hypercholesterolemia research. This review will examine issues in the measurement of adherence to therapy for chronic diseases in a clinical setting, and, specifically, the measurement of adherence to treatment for hypercholesterolemia in clinical trials.