title: Dihydropyridine calcium channel blockers and cardiovascular outcomes in elderly patients: a population-based study.
abstract: BACKGROUND
  Dihydropyridine calcium channel blockers are widely used for the treatment of hypertension and angina. Despite safety concerns associated with short-acting agents, increasing evidence supports the safety of long-acting dihydropyridines. Although amlodipine is the best studied of these, there are few studies comparing it with nifedipine.
  
  
  OBJECTIVE
  To examine the association between hospitalization for acute coronary syndromes and treatment with amlodipine or extended-release nifedipine in patients 65 years of age and older. The primary objective was a composite of hospital admission for angina or acute myocardial infarction.
  
  
  METHODS
  The present population-based, retrospective cohort study used linked health care databases from Ontario. Propensity scores were used to identify highly similar patients started on amlodipine or extended-release nifedipine between April 1997 and March 2002. Time-to-event analysis was conducted using Cox proportional hazards models.
  
  
  RESULTS
  The analysis included 24,190 patients (44% male; mean age 75 years) treated with amlodipine or extended-release nifedipine (n=12,095 each). The number of patients reaching the primary end point was 362 (3%) and 294 (2.4%) in the amlodipine and nifedipine groups, respectively. The groups were similar in a large number of demographic and clinical characteristics. No significant differences were observed among users of extended-release nifedipine (adjusted hazard ratio 0.91, 95% CI 0.74 to 1.13) relative to amlodipine.
  
  
  CONCLUSIONS
  These findings suggest that amlodipine and extended-release nifedipine are not associated with differential rates of acute coronary events in older patients.
authors.affiliation: Department of Pharmacie, Sunnybook Health Sciences Centre, University of Toronto, Ontario, Canada. claudia.bucci@sunnybrook.ca
authors.forename: Claudia
authors.initials: C
authors.lastname: Bucci
authors.forename: Muhammad M
authors.initials: MM
authors.lastname: Mamdani
authors.forename: David N
authors.initials: DN
authors.lastname: Juurlink
authors.forename: Jack V
authors.initials: JV
authors.lastname: Tu
mesh_terms: D054058:Acute Coronary Syndrome / Q000188:drug therapy*; D000368:Aged; D017311:Amlodipine / Q000009:adverse effects / Q000627:therapeutic use*; D000787:Angina Pectoris / Q000188:drug therapy*; D002121:Calcium Channel Blockers / Q000009:adverse effects / Q000627:therapeutic use*; D002170:Canada; D015331:Cohort Studies; D003692:Delayed-Action Preparations; D005260:Female; D006306:Health Surveys; D006760:Hospitalization / Q000706:statistics & numerical data*; D006801:Humans; D008297:Male; D009203:Myocardial Infarction / Q000188:drug therapy*; D009543:Nifedipine / Q000009:adverse effects / Q000627:therapeutic use*; D016016:Proportional Hazards Models; D012189:Retrospective Studies
chemical_list: D002121:Calcium Channel Blockers; D003692:Delayed-Action Preparations; D017311:Amlodipine; D009543:Nifedipine