Depression and self-reported functional status: impact on mortality following acute myocardial infarction.
OBJECTIVE
The cause of increased post-AMI (acute myocardial infarction) mortality associated with depression remains poorly elucidated. The objective of this study was to examine the extent to which self-reported cardiac functional status accounted for depression-mortality associations following AMI.


METHODS
Using a prospective cohort design (n = 1941), the authors obtained self-reported measures of depression and developed profiles of the patients' pre-hospitalization cardiac risks, co-morbid conditions and drugs and revascularization procedures during or following index AMI hospitalization. To create these profiles, the patients' self-reports were retrospectively linked to no less than 12 years' worth of previous hospitalization data. Mortality rates 2 years after acute MI were examined with and without sequential risk adjustment for age, sex, income, cardiovascular risk, co-morbid conditions, selected process-of-care factors and self-reported cardiac functional status.


RESULTS
Depression was strongly correlated with 2-year mortality rate [crude hazard ratio (HR) of severe vs. minimal depression category, 2.48 (95% CI 1.20-5.15); P = 0.01]. However, after sequential adjustment for age, sex, income and self-reported cardiac functional status, the effect of depression was greatly attenuated [adjusted HR for severe vs. minimal depression category, 1.35 (95% CI 0.63-2.87); P = 0.44]. Cardiac risk factors and non-cardiac co-morbidities had negligible explanatory effect.


CONCLUSIONS
The main factor determining the increased mortality rate in depressed patients is self-reported cardiac functional status. Efforts to address increased mortality in depressed patients with cardiovascular illnesses should focus on processes that impact cardiac functional status.
Kurdyak
Paul A
PA
Centre for Addiction and Mental Health and Institute for Clinical Evaluative Sciences, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada.
Chong
Alice
A
Gnam
William H
WH
Goering
Paula
P
Alter
David A
DA
D000208:Acute Disease; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D002317:Cardiovascular Agents / Q000008:administration & dosage; D015897:Comorbidity; D003863:Depression / Q000209:etiology*; D005260:Female; D006304:Health Status; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000150:complications* / Q000401:mortality; D009204:Myocardial Revascularization; D011446:Prospective Studies; D012307:Risk Factors; D057566:Self Report; D012720:Severity of Illness Index; D012737:Sex Factors; D012959:Socioeconomic Factors; D055815:Young Adult
D002317:Cardiovascular Agents