Poor adherence to placebo or amiodarone therapy predicts mortality: results from the CAMIAT study. Canadian Amiodarone Myocardial Infarction Arrhythmia Trial.
OBJECTIVE
This study examined the relationship between adherence, mortality, and psychosocial factors.


METHODS
Subjects were 1141 patients participating in the Canadian Amiodarone Myocardial Infarction Arrhythmia Trial. Poor adherence to study medication (amiodarone or placebo), measured by pill count over 2 years, was defined as the lower 20th percentile of the pill count distribution. Predictors of adherence were also studied and included demographic and cardiac variables and, in a subset of participants (N = 671), measures of depression, distress, hostility, and social support.


RESULTS
In survival analysis controlling for cardiac and demographic variables, poor adherence in the placebo and amiodarone groups was associated with an increased risk of sudden cardiac death (relative risk (RR) = 2.11, 95% confidence interval (CI) = 1.03-4.56, p < .05; and RR = 3.15, 95% CI = 1.34-7.44, p < .01, respectively), total cardiac mortality (RR = 2.04, 95% CI = 1.12-3.72, p < .02; and RR = 2.49, 95% CI = 1.32-4.72, p < .01, respectively), and all-cause mortality (RR = 2.25, 95% CI = 1.27-3.97, p < .001; and RR = 2.34, 95% CI = 1.32-4.17, p < .004, respectively). Logistic regression analysis identified two predictors of poor adherence to placebo: age > 70 years (odds ratio = 2.18, 95% CI = 1.11-4.29, p < .03) and social activities in the month before the index heart attack (odds ratio = 1.02, 95% CI = 1.00-1.04, p < .05).


CONCLUSIONS
Poor adherence is associated with a greater risk of mortality. The relationship between adherence and social activities suggests a higher motivation to adhere to treatment in individuals more engaged in enjoyable activities.
Irvine
J
J
The Toronto Hospital, Department of Psychiatry, University of Toronto, Ontario, Canada. jane.irvine@utoronto.ca
Baker
B
B
Smith
J
J
Jandciu
S
S
Paquette
M
M
Cairns
J
J
Connolly
S
S
Roberts
R
R
Gent
M
M
Dorian
P
P
D000368:Aged; D000638:Amiodarone / Q000627:therapeutic use*; D000889:Anti-Arrhythmia Agents / Q000627:therapeutic use*; D001145:Arrhythmias, Cardiac / Q000175:diagnosis / Q000188:drug therapy* / Q000401:mortality*; D002170:Canada / Q000453:epidemiology; D016757:Death, Sudden, Cardiac / Q000453:epidemiology*; D003866:Depressive Disorder / Q000175:diagnosis / Q000523:psychology; D004311:Double-Blind Method; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis / Q000188:drug therapy* / Q000401:mortality*; D010349:Patient Compliance / Q000706:statistics & numerical data*; D011237:Predictive Value of Tests; D011379:Prognosis; D011446:Prospective Studies; D011795:Surveys and Questionnaires; D016896:Treatment Outcome
D000889:Anti-Arrhythmia Agents; D000638:Amiodarone