Recognizing Increased Risk of Depressive Comorbidity after Myocardial Infarction: Looking for 4 Symptoms of Anxiety-Depression

Abstract

Background: Screening for depression in myocardial infarction (MI) patients must be improved: (1) depression often goes unrecognized and (2) anxiety has been largely overlooked as an essential feature of depression in these patients. We therefore examined the co-occurrence of anxiety and depression after MI, and the validity of a brief mixed anxiety-depression index as a simple way to identify post-MI patients at increased risk of comorbid depression. Methods: One month after MI, 176 patients underwent a psychiatric interview and completed the Beck Depression Inventory (BDI) and the Symptoms of Anxiety-Depression index (SAD₄) containing four symptoms of anxiety (tension, restlessness) and depression (feeling blue, hopelessness). Results: Thirty-one MI patients (18%) had comorbid depression and 37 (21%) depressive or anxiety disorder. High factor loadings and item-total correlations (SAD₄, α = 0.86) confirmed that symptoms of anxiety and depression co-occurred after MI. Mixed anxiety-depression (SAD₄≧3) was present in 90% of depressed MI patients and in 100% of severely depressed patients. After adjustment for standard depression symptoms (BDI; OR = 4.4, 95% CI 1.6–12.1, p = 0.004), left ventricular ejection fraction, age and sex, mixed anxiety-depression symptomatology was associated with an increased risk of depressive comorbidity (OR = 11.2, 95% CI 3.0–42.5, p < 0.0001). Mixed anxiety-depression was also independently associated with depressive or anxiety disorder (OR = 9.2, 95% CI 3.0–27.6, p < 0.0001). Conclusions: Anxiety is underrecognized in post-MI patients; however, the present findings suggest that anxiety symptomatology should not be overlooked in these patients. Depressive comorbidity after MI is characterized by symptoms of mixed anxiety-depression, after controlling for standard depression symptoms. The SAD₄ represents an easy way to recognize the increased risk of post-MI depression.