Patients who do not stay on clopidogrel after a heart attack for the NICE-recommended 12 months are more than 2.5 times more likely to die or experience a further non-fatal heart attack than those who see out the full year of treatment, new research reports.
Researchers also found that post-myocardial infarction patients who discontinue clopidogrel within 12 months have a 45% higher risk of death or a further non-fatal heart attack than those who had never taken the treatment.
Evidence of a powerful rebound effect for patients taking clopidogrel emerged after a study of records for 7,543 patients in England and Wales admitted to hospital with acute coronary syndrome between 2003 and 2009, 4,650 of whom were prescribed clopidogrel within three months of discharge.
About half of patients with non-ST-elevation MI (NSTEMI), and roughly the same proportion of those who had an ST-elevation MI (STEMI), started taking clopidogrel but then stopped before the end of the 12-month watershed. The hazard ratio for all-cause mortality or non-fatal MI in these patients was 2.62 compared with those who continued treatment.
The results, published in the latest issue of the European Heart Journal, showed discontinuation was more likely in older patients or those who had bleeding. In the same patients, 84-89% were still taking statins a year later, suggesting general compliance was not the issue.
Study leader Professor Keith Fox, professor of cardiology at the University of Edinburgh, said: ‘Although there was a drop in clopidogrel prescribing in the first year, these results still represent better adherence in the year after discharge than seen in some other studies. The key message for GPs is to urge continued adherence.’
Dr Terry McCormack, council member of the Primary Care Cardiovascular Society and a GP in Whitby, Yorkshire, said the study emphasised the need for GPs to warn patients in advance of clopidogrel side-effects, so that they did not use these as a reason to give up: ‘The major reason people stop taking clopidogrel is that they get bruising. GPs need to tell them beforehand that if they get bruising they should report it.’
Clopidogrel is marketed by Bristol-Myers Squibb under the brand name Plavix. Dr Mahendra Sibartie, director of cardiovascular and metabolic at Bristol-Myers Squibb UK, said: ‘The findings of this research clearly reinforce for GPs the need for patients to take the full course of medication, as recommended by NICE guidelines.’