Impact of adherence to antihypertensive agents on clinical outcomes and hospitalization costs.
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.
Dragomir
Alice
A
Faculty of Pharmacy, University of Montreal, Montreal, Quebec, Canada.
Côté
Robert
R
Roy
Louise
L
Blais
Lucie
L
Lalonde
Lyne
L
Bérard
Anick
A
Perreault
Sylvie
S
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
D000959:Antihypertensive Agents