Depression and risk of sudden cardiac death after acute myocardial infarction: testing for the confounding effects of fatigue.
OBJECTIVE
This study examined the impact of depressive symptoms and social support on 2-year sudden cardiac death (SCD) risk, controlling for fatigue symptoms.


METHODS
Myocardial infarction (MI) patients (N = 671) participating in the Canadian Amiodarone Myocardial Infarction Arrhythmia Trial completed measures of depression, hostility, and social support.


RESULTS
After controlling for significant biological predictors, psychosocial predictors of increased SCD risk in the survival analysis were greater social network contacts (RR = 1.04; 95% CI = 1.01-1.06; p < .007), lower social participation (RR = 0.98; 95% CI = 0.96-1.00; p < .05), and, in placebo-treated patients, elevated depressive symptoms (RR = 2.45; 95% CI = 1.14-5.35; p < .02). Fatigue was associated with SCD (RR = 1.31; 95% CI = 1.11-1.53; p < .001), and, when included in the model, diminished the influence of depression (RR = 1.73; 95% CI = 0.75-3.98; p = .20). When the cognitive-affective depressive symptoms were examined separately from somatic symptoms, there was a trend for an association between cognitive-affective symptoms and SCD in placebo-treated patients after controlling for fatigue (RR = 1.09; 95% CI = 0.99-1.19, p < .06).


CONCLUSIONS
Symptoms of depression and fatigue overlap in patients with MI. The trend for the cognitive-affective symptoms of depression to be associated with SCD risk, even after controlling for dyspnea/fatigue, suggests that the association between depression and mortality after AMI cannot be entirely explained as a confound of cardiac-related fatigue. The independent contribution of social participation suggests a role of both depressive symptomatology and social factors in influencing mortality risk after MI.
Irvine
J
J
Toronto General Hospital, University Health Network, Department of Psychiatry, University of Toronto, Ontario, Canada. jane.irvine@utoronto.ca
Basinski
A
A
Baker
B
B
Jandciu
S
S
Paquette
M
M
Cairns
J
J
Connolly
S
S
Roberts
R
R
Gent
M
M
Dorian
P
P
D000203:Activities of Daily Living; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000638:Amiodarone / Q000627:therapeutic use*; D000889:Anti-Arrhythmia Agents / Q000627:therapeutic use*; D002170:Canada; D015986:Confounding Factors, Epidemiologic; D016757:Death, Sudden, Cardiac / Q000209:etiology* / Q000517:prevention & control*; D003863:Depression / Q000150:complications*; D005221:Fatigue / Q000150:complications*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000150:complications / Q000401:mortality* / Q000517:prevention & control / Q000523:psychology*; D016016:Proportional Hazards Models; D012306:Risk; D055502:Secondary Prevention; D012944:Social Support; D011795:Surveys and Questionnaires; D016019:Survival Analysis
D000889:Anti-Arrhythmia Agents; D000638:Amiodarone