title: Concomitant use of calcium channel blockers with dual antiplatelet therapy and re-hospitalization for acute coronary syndrome.
abstract: BACKGROUND
  Existing studies suggested that concomitant use of calcium channel blockers (CCBs) may interfere with the antiplatelet effect of clopidogrel. The objective of this study was to examine the effect of concomitant use of CCBs and clopidogrel on risks of acute coronary syndrome (ACS) re-hospitalization in patients receiving percutaneous coronary intervention.
  
  
  METHODS
  Using the Taiwan National Health Insurance Research Database, we identified 51 925 patients who were admitted for newly diagnosed ACS, received percutaneous coronary intervention, and used clopidogrel within 1 year after discharge. We further stratified them into three groups based on their uses of guideline-recommended secondary prevention medications for ACS (fully, partially, and non-compliant groups) to assess the potential modification effect of guideline compliance. For each group, we conducted a 1:1 propensity score matching to minimize selection bias. Cox proportional hazard models were used to investigate the effect of concomitant use of CCBs (overall, subclasses, and individual CCBs) and clopidogrel on risks of ACS re-hospitalization.
  
  
  RESULTS
  Concomitant use of CCBs in patients discharged with clopidogrel was significantly associated with a lower risk of ACS re-hospitalization in the fully compliant group (HRfully compliant= 0.82 [95% confidence interval 0.75-0.89], p < 0.001) but was associated with increased risk of ACS re-hospitalization in the non-compliant group (HRnon-compliant= 1.22 [1.03-1.45], p = 0.0252).
  
  
  CONCLUSIONS
  Different guideline compliance of secondary prevention medications could modify the potential drug-drug interaction between clopidogrel and CCBs. Concomitant use of CCBs and clopidogrel was significantly associated with increased risk of ACS re-hospitalization in ACS patients not compliant to guideline-recommended secondary prevention drugs. Copyright © 2017 John Wiley & Sons, Ltd.
authors.affiliation: Graduate Institute of Clinical Pharmacy, College of Medicine, National Taiwan University, Taipei, Taiwan.|School of Pharmacy, College of Medicine, National Taiwan University, Taipei, Taiwan.
authors.forename: Chen-Yu
authors.initials: CY
authors.lastname: Wang
authors.affiliation: Graduate Institute of Clinical Pharmacy, College of Medicine, National Taiwan University, Taipei, Taiwan.|School of Pharmacy, College of Medicine, National Taiwan University, Taipei, Taiwan.|Department of Pharmacy, National Taiwan University Hospital, Taipei, Taiwan.
authors.forename: Zhen-Fang
authors.initials: ZF
authors.lastname: Lin
authors.affiliation: Department of Internal Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan.
authors.forename: Chii-Ming
authors.initials: CM
authors.lastname: Lee
authors.affiliation: Institute of Health and Welfare, National Yang-Ming University, Taipei, Taiwan.
authors.forename: Yi-Wen
authors.initials: YW
authors.lastname: Tsai
authors.affiliation: Department of Pharmaceutical Health Services Research, School of Pharmacy, University of Maryland, Baltimore, MD, USA.
authors.forename: Ting-Ying
authors.initials: TY
authors.lastname: Huang
authors.affiliation: Graduate Institute of Clinical Pharmacy, College of Medicine, National Taiwan University, Taipei, Taiwan.|School of Pharmacy, College of Medicine, National Taiwan University, Taipei, Taiwan.|Department of Pharmacy, National Taiwan University Hospital, Taipei, Taiwan.
authors.forename: Li-Jiuan
authors.initials: LJ
authors.lastname: Shen
authors.affiliation: Graduate Institute of Clinical Pharmacy, College of Medicine, National Taiwan University, Taipei, Taiwan.|School of Pharmacy, College of Medicine, National Taiwan University, Taipei, Taiwan.|Department of Pharmacy, National Taiwan University Hospital, Taipei, Taiwan.
authors.forename: Fei-Yuan
authors.initials: FY
authors.lastname: Hsiao
mesh_terms: D054058:Acute Coronary Syndrome / Q000503:physiopathology / Q000628:therapy*; D000368:Aged; D000369:Aged, 80 and over; D002121:Calcium Channel Blockers / Q000008:administration & dosage*; D000077144:Clopidogrel; D016208:Databases, Factual; D004347:Drug Interactions; D004359:Drug Therapy, Combination; D005260:Female; D019983:Guideline Adherence; D006801:Humans; D008297:Male; D008875:Middle Aged; D010359:Patient Readmission / Q000706:statistics & numerical data*; D062645:Percutaneous Coronary Intervention / Q000379:methods; D010975:Platelet Aggregation Inhibitors / Q000008:administration & dosage*; D017410:Practice Guidelines as Topic; D016016:Proportional Hazards Models; D055502:Secondary Prevention / Q000379:methods; D013624:Taiwan; D013988:Ticlopidine / Q000008:administration & dosage / Q000031:analogs & derivatives
chemical_list: D002121:Calcium Channel Blockers; D010975:Platelet Aggregation Inhibitors; D000077144:Clopidogrel; D013988:Ticlopidine
keywords: acute coronary syndrome (ACS); calcium channel blockers (CCBs); clopidogrel; percutaneous coronary intervention (PCI); pharmacoepidemiology; re-hospitalization