Depression and cardiovascular morbidity and mortality: cause or consequence?
BACKGROUND
Depression after myocardial infarction has been associated with increased cardiovascular mortality. This study assessed whether depressive symptoms were associated with adverse outcomes in people with a history of an acute coronary syndrome, and evaluated possible explanations for such an association.


RESULTS
Depressive symptoms were assessed using the General Health Questionnaire at least 5 months after hospital admission for acute myocardial infarction or unstable angina in 1130 participants of the Long-Term Intervention with Pravastatin in Ischaemic Disease (LIPID) Study, a multicentre, placebo-controlled, clinical trial of cholesterol-lowering treatment. Cardiovascular symptoms, self-rated general health, cardiovascular risk factors, employment status, social support and life events were also assessed at the baseline visit. Cardiovascular death (n=114), non-fatal myocardial infarction (n=108), non-fatal stroke (n=53) and unstable angina (n=274) were documented during a median follow-up period of 8.1 years. Individuals with depressive symptoms (General Health Questionnaire score >/=5; 22% of participants) were more likely to report angina, dyspnoea, claudication, poorer general health, not being in paid employment, few social contacts and/or adverse life events (P<0.05 for all). There was a modest association between depressive symptoms and cardiovascular events (hazard ratio [HR] 1.42, 95% confidence interval [CI] 1.13-1.77), but not cardiovascular death (HR 1.12. 95% CI 0.71-1.77). After adjustment for symptoms related to cardiovascular disease, the HR for cardiovascular events was 1.22 (95% CI 0.97-1.53). After further adjustment for employment status, social support and life events, the HR was 1.13 (95% confidence interval 0.87-1.47).


CONCLUSIONS
There was no significant association between depressive symptoms and fatal or non-fatal cardiovascular events after adjustment for cardiovascular symptoms associated with poorer prognosis. Previously observed associations between depression and cardiovascular mortality may not be causal.
Stewart
Ralph A H
RA
Green Lane Hospital, Auckland, New Zealand. rstewart@adhb.govt.nz
North
Fiona M
FM
West
Teena M
TM
Sharples
Katrina J
KJ
Simes
R John
RJ
Colquhoun
David M
DM
White
Harvey D
HD
Tonkin
Andrew M
AM
D000328:Adult; D000368:Aged; D001315:Australia / Q000453:epidemiology; D002318:Cardiovascular Diseases / Q000150:complications* / Q000453:epidemiology / Q000523:psychology; D015986:Confounding Factors, Epidemiologic; D003863:Depression / Q000150:complications*; D018572:Disease-Free Survival; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009520:New Zealand / Q000453:epidemiology; D011379:Prognosis; D016016:Proportional Hazards Models; D012307:Risk Factors; D012720:Severity of Illness Index; D012959:Socioeconomic Factors