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Adherence to evidence-based therapies

Clinical bottom line

Within six month of discharge, up to 20% of patients with myocardial infarction or unstable angina are no longer taking their medication


It is well known that patients do not take the medicines prescribed for them. The extent of this lack of adherence varies with the population and the medicine. Adverse events can be a major driver for lack of adherence, as can be the consequences of lack of adherence.


KA Eagle et al. Adherence to evidence-based therapies after discharge for acute coronary syndromes: an ongoing prospective, observational study. American Journal of Medicine 2004 117: 73-81.


The study involved patients enrolled in a an ongoing prospective study of a sample of patients with acute coronary syndromes from North and South America, Europe, and Australasia. Here those enrolled between 1999 and 2003 constituted the sample, if they had a discharge diagnosis of myocardial infarction or unstable angina, and had follow up data at 5 to 12 months after discharge.


There were 21,408 patients enrolled, and 13,830 (65%) were alive at 5 to 12 months after discharge. Median age was 65 years, and 32% were women.

At a median of six months after discharge:


The value of this study is that it is large and international. It concentrates on patients who have had a very serious scare, and who would be expected to be highly incentivised to take medicines prescribed for them. What is impressive is that 80%-90% of the medicines were still taken at six months. This is higher than is seen in other studies.