[Compliance to therapy -- its importance in research and clinical practice]

Compliance, defined as patients behaviour to treatment schedule over time, specially in chronic diseases, is an important parameter to be measured in clinical trials. Compliance to a specific drug may compromise the final efficacy expected result assumed by phase I II and III studies. The medication events monitors systems (MEMS) appeared to get a more specific and sensitive measurement than the classic counting pills and drug or markers levels to analyses of compliance. The authors made a revision of literature in order to evaluate the benefits of compliance measurement in trials (specially hypertension as a paradigm of chronic disease) and clinical practice. Partial compliance with antihypertensive treatment could be an obstacle to an effective control or to demonstrate long term efficacy on decreasing morbidity and mortality. A short discussion is made about the possible benefits of using MEMS on clinical trials to evaluate patient's quality of life and behaviour to long term treatment for chronic diseases.