Cognitive and somatic symptoms of depression are associated with medical comorbidity in patients after acute myocardial infarction.

BACKGROUND: Depression is common in patients with acute myocardial infarction (AMI) and is associated with adverse health outcomes. However, the extent to which clinical depression is related to comorbid medical conditions is unknown. This study examined the degree of association between clinical depression and medical comorbidity in patients hospitalized with AMI.
METHODS: Two thousand four hundred and eighty-one depressed or socially isolated patients with AMI were enrolled, as part of the National Heart, Lung, and Blood Institute-sponsored Enhancing Recovery in Coronary Heart Disease clinical trial. A structured interview was used to diagnose major and minor depression and dysthymia; severity of depression was measured by the Hamilton Rating Scale for Depression and the Beck Depression Inventory. Level of social support was measured by the ENRICHD Social Support Instrument. A modified version of the Charlson Comorbidity Index was used to measure the cumulative burden of medical comorbidity.
RESULTS: The adjusted odds ratios (ORs) for having major depression increased linearly with medical comorbidity (ORs 1.6, 2.2, 2.7 for each increasing medical comorbidity category). This relationship remained after adjusting for coronary heart disease severity (ORs 1.4, 1.7, 1.9, P <.001). The relationship between severity of depression and medical comorbidity was also maintained after excluding somatic symptoms of depression (F = 21.5, P <.0001).
CONCLUSIONS: Patients with AMI and clinical depression have significantly greater levels of medical comorbidity than nondepressed, socially isolated patients. Further research is needed to determine whether comorbid medical illness contributes to the more frequent rehospitalizations and increased risk of mortality associated with depression.