title: Impact of adherence to antihypertensive agents on clinical outcomes and hospitalization costs.
abstract: BACKGROUND
  Cardiovascular diseases (CVD) represent a heavy economic burden on individuals, health services, and society. Low adherence to antihypertensive (AH) agents is acknowledged as a major contributor to the lack of blood pressure control, and may have a significant impact on clinical outcomes and healthcare costs.
  
  
  OBJECTIVE
  To evaluate the impact of low adherence to AH agents on cardiovascular outcomes and hospitalization costs.
  
  
  METHODS
  A cohort of 59,647 patients with essential hypertension was reconstructed from the Régie de l'assurance maladie du Québec and Med-Echo databases. Subjects included were between 45 and 85 years of age, without any evidence for symptomatic CVD, newly treated with AH agents between 1999 and 2002 and followed-up for a 3-year period. Adherence to AH agents was categorized as >or=80% or <80%. The adjusted odds ratio (OR) for CVD events between the 2 adherence groups was estimated using a polytomous logistic analysis. A 2-part model was applied for hospitalization costs.
  
  
  RESULTS
  Patients with low adherence were more likely to have coronary disease (OR, 1.07; 95% confidence interval [CI], 1.00-1.13), cerebrovascular disease (OR, 1.13; 95% CI, 1.03-1.25), and chronic heart failure (OR, 1.42; 95% CI, 1.27-1.58) within the 3-year follow-up period. Among hospitalized patients, low adherence to AH therapy was associated with increased costs by approximately $3574 (95% CI, $2897-$4249) per person within a 3-year period.
  
  
  CONCLUSIONS
  Low adherence to AH agents is correlated with a higher risk of vascular events, hospitalization, and greater healthcare costs. An increased level of adherence to AH agents should provide a better health status for individuals and a net economic gain.
authors.affiliation: Faculty of Pharmacy, University of Montreal, Montreal, Quebec, Canada.
authors.forename: Alice
authors.initials: A
authors.lastname: Dragomir
authors.forename: Robert
authors.initials: R
authors.lastname: Côté
authors.forename: Louise
authors.initials: L
authors.lastname: Roy
authors.forename: Lucie
authors.initials: L
authors.lastname: Blais
authors.forename: Lyne
authors.initials: L
authors.lastname: Lalonde
authors.forename: Anick
authors.initials: A
authors.lastname: Bérard
authors.forename: Sylvie
authors.initials: S
authors.lastname: Perreault
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000959:Antihypertensive Agents / Q000191:economics / Q000627:therapeutic use*; D002318:Cardiovascular Diseases / Q000191:economics* / Q000209:etiology; D002561:Cerebrovascular Disorders / Q000191:economics / Q000209:etiology; D015331:Cohort Studies; D003324:Coronary Artery Disease / Q000191:economics / Q000209:etiology; D004359:Drug Therapy, Combination; D005260:Female; D006333:Heart Failure / Q000191:economics / Q000209:etiology; D017722:Hospital Charges / Q000706:statistics & numerical data*; D006760:Hospitalization / Q000191:economics / Q000706:statistics & numerical data; D006801:Humans; D006973:Hypertension / Q000150:complications / Q000188:drug therapy* / Q000191:economics; D007345:Insurance Claim Review / Q000706:statistics & numerical data; D008297:Male; D008875:Middle Aged; D012737:Sex Factors; D016896:Treatment Outcome; D016903:Drug Monitoring
chemical_list: D000959:Antihypertensive Agents