Clopidogrel discontinuation after myocardial infarction and risk of thrombosis: a nationwide cohort study.
OBJECTIVE
The benefit of extending clopidogrel treatment beyond the 12-month period recommended in current guidelines after myocardial infarction (MI) is debated. We analysed the risk of adverse cardiovascular outcomes after discontinuation of 12 months of clopidogrel treatment.


RESULTS
This Danish retrospective nationwide study included all patients treated with clopidogrel after discharge from a first-time MI during 2004-09. The risk of death or recurrent MI after the discontinuation of clopidogrel was studied by multivariable Poisson regression models. Patients treated with and without percutaneous coronary intervention (PCI) were analysed separately. The follow-up was 18 months. Of the 29,268 patients included, 3214 (11.0%) experienced death or recurrent MI. There were 9819 (33.6%) patients treated only medically and 19,449 (66.4%) patients treated with PCI. Twelve months after the index MI, for patients treated only medically, the risk of death or recurrent MI in the first 90-day period of clopidogrel discontinuation was 1.07 (0.65-1.76; P= 0.79) [adjusted incidence rate ratio (IRR) and 95% confidence interval] compared with the next 90-day period of discontinuation. For patients treated with PCI, the corresponding IRR was 1.59 (1.11-2.30; P= 0.013). The risk of recurrent MI yielded an IRR of 0.77 (0.36-1.67; P= 0.51) for patients treated only medically and 1.87 (1.11-3.15; P= 0.019) for PCI-treated patients.


CONCLUSIONS
Discontinuation of clopidogrel 12 months after MI is associated with an increased risk of death or recurrent MI in the first 90 days of discontinuation compared with the next 90-day period of discontinuation for patients treated with PCI, but not for patients not treated with PCI.
Department of Cardiology, Copenhagen University Hospital Gentofte, Hellerup, Denmark. mc@heart.dk
Mette
M
Charlot
Lars Hougaard
LH
Nielsen
Jesper
J
Lindhardsen
Ole
O
Ahlehoff
Anne-Marie S
AM
Olsen
Morten Lock
ML
Hansen
Peter Riis
PR
Hansen
Jan Kyst
JK
Madsen
Lars
L
Køber
Gunnar H
GH
Gislason
Christian
C
Torp-Pedersen
D000328:Adult; D000368:Aged; D000077144:Clopidogrel; D003718:Denmark / Q000453:epidemiology; D004334:Drug Administration Schedule; D004812:Epidemiologic Methods; D005260:Female; D006083:Graft Occlusion, Vascular / Q000209:etiology / Q000401:mortality; D006470:Hemorrhage / Q000139:chemically induced; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000188:drug therapy* / Q000401:mortality; D062645:Percutaneous Coronary Intervention / Q000379:methods / Q000401:mortality; D010975:Platelet Aggregation Inhibitors / Q000627:therapeutic use*; D011475:Prosthesis Failure; D012008:Recurrence; D015607:Stents; D013927:Thrombosis / Q000209:etiology*; D013988:Ticlopidine / Q000031:analogs & derivatives* / Q000627:therapeutic use; D028761:Withholding Treatment
D010975:Platelet Aggregation Inhibitors; D000077144:Clopidogrel; D013988:Ticlopidine