Psychological symptom clusters, psychiatric comorbidity and poor self-reported health status following myocardial infarction

Abstract

Depression is a risk factor for adverse outcomes following myocardial infarction (MI). However, the importance of various other psychological factors is less well established. The purpose is (a) explore the degree to which self-reported psychological symptoms in post-MI patients represent one or more underlying dimensions and (b) examine whether psychological symptom profiles based on these dimensions are differentially associated with major depressive disorder (MDD) and anxiety disorder (AD), and impaired health status. Two months post-MI, the Beck Depression Inventory, State-Trait Anxiety Inventory, and Global Mood Scale were used to measure symptoms of depression, anxiety, and mood status in 324 patients. The Composite International Diagnostic Interview was administered to diagnose DSM-IV MDD and AD. Health status was assessed by the Seattle Angina Questionnaire. Principal component analysis revealed 4 essential features of post-MI distress: depressed affect, anxious apprehension, positive affect, and emotional exhaustion. Cluster analysis using these components identified 3 subgroups with different symptom profiles: A no distress subgroup (high positive affect, low on the remaining components), a first increased distress subgroup (ID1; elevated anxious apprehension/emotional exhaustion scores and decreased positive affect, p<.001, but absence of depressed affect, p=.56), and a second increased distress subgroup (ID2; decreased positive affect and elevated scores on the other components, all p<.001). Both increased distress subgroups were more likely to have psychiatric disorder (ID1: odds ratio [OR]=5.4, 95% confidence interval [CI]=1.3-22.1, p=.018; ID2: OR=27.1, 95% CI=6.4-114.7, p<.0001) and worse health status (ID1: -.38<B<-.12; all p<.05; ID2: -.48<B<-.20; all p<.05). In addition to standard depressive symptoms, other affective components are important in understanding emotional adjustment in post-MI patients. These components are closely related to psychiatric comorbidity and poor health status post-MI.