title: Prevalence and risk factors of clopidogrel non-response among Saudi patients undergoing coronary angiography.
abstract: OBJECTIVE
  To estimate the prevalence of clopidogrel non-response and identify its risk factors among Saudi patients.
  
  
  METHODS
  This cross-sectional study was conducted at Prince Sultan Cardiac Center, Riyadh, Kingdom of Saudi Arabia between January and June 2013, to assess the degree of platelet inhibition using the VerifyNow assay (Accumetrics, San Diego, CA, USA) after receiving clopidogrel standard loading dose. Clopidogrel resistance was defined as ≤15% platelet inhibition or greater than 213 P2Y12 reaction units (PRU).
  
  
  RESULTS
  Three hundred and four patients were included in the study. The mean age was 60.3 ± 11.4 years, and 73% were males. Clopidogrel doses were 300 mg (57%), 600 mg (27%), and 75 mg (16%). All patients used aspirin (81 mg in 94%). Approximately 66% (200/304) showed in vitro clopidogrel non-response, 54% had low platelet inhibitions, and 61% had high post-loading PRU. Using multivariate regression analysis that included all significant characteristics; only diabetes (odds ratio [OR]: 2.36, 95% confidence interval [CI]: 1.30-4.27, p=0.005) and higher preloading PRU (OR: 2.39, 95% CI: 1.40-4.11, p=0.002) remained significantly associated with higher clopidogrel non-response while myocardial infarction (OR: 0.34, 95% CI: 0.15-0.81, p=0.014) remained significantly associated with lower clopidogrel non-response. The associations of morbid obesity and diuretics use with higher clopidogrel non-response were slightly attenuated.
  
  
  CONCLUSIONS
  Our findings indicate a high rate of clopidogrel in-vitro non-response among Saudi patients undergoing coronary angiography.
authors.affiliation: Department of Adult Cardiology, Prince Sultan Cardiac Center, Riyadh, Kingdom of Saudi Arabia. E-mail. himsakr@gmail.com.
authors.forename: Haitham I
authors.initials: HI
authors.lastname: Sakr
authors.forename: Hussein S
authors.initials: HS
authors.lastname: Alamri
authors.forename: Abdulrahman M
authors.initials: AM
authors.lastname: Almoghairi
authors.forename: Ashraf A
authors.initials: AA
authors.lastname: Alkhudair
authors.forename: Ali S
authors.initials: AS
authors.lastname: AlMasood
mesh_terms: D000328:Adult; D000368:Aged; D001241:Aspirin / Q000494:pharmacology / Q000627:therapeutic use; D001792:Blood Platelets / Q000187:drug effects*; D000077144:Clopidogrel; D017023:Coronary Angiography; D003324:Coronary Artery Disease / Q000188:drug therapy; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009203:Myocardial Infarction / Q000453:epidemiology; D016017:Odds Ratio; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology* / Q000627:therapeutic use; D015995:Prevalence; D012307:Risk Factors; D012529:Saudi Arabia / Q000453:epidemiology; D013988:Ticlopidine / Q000031:analogs & derivatives* / Q000494:pharmacology / Q000627:therapeutic use; D017211:Treatment Failure
chemical_list: D010975:Platelet Aggregation Inhibitors; D000077144:Clopidogrel; D013988:Ticlopidine; D001241:Aspirin
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