CO-MORBID SYMPTOMS OF DEPRESSION AND ANXIETY AND BIO-BEHAVIORAL RESPONSE TO STRESS IN PATIENTS WITH HEART FAILURE

Abstract

OF DISSERTATION CO-MORBID SYMPTOMS OF DEPRESSION AND ANXIETY AND BIOBEHAVIORAL RESPONSE TO STRESS IN PATIENTS WITH HEART FAILURE Heart failure (HF) is a major public health problem throughout the world. It accounts for one death certificate among nine in the United States. Heart failure and sudden death combined are responsible for the largest number of deaths in America. The total costs of HF in the United States are estimated to be $37 billion each year. Despite substantial medical and surgical advances related to treatment of HF, it remains a very costly condition with high mortality and morbidity rates. Although biological factors contribute to high morbidity and mortality in HF, there are many unexplored psychosocial factors that also likely contribute to these rates. Thus, the purpose of this dissertation was to examine the association between some of the psychosocial factors (i.e. depression, anxiety, comorbid depression and anxiety, stress, cognitive appraisal, and coping) and health outcomes as defined by rehospitalisation and mortality among HF patients. The first paper is a report of longitudinal study of 1,260 patients with HF. The purpose of the study was to determine whether co-morbid symptoms of depression and anxiety are associated with all-cause mortality or rehospitalization for cardiac causes in patients with HF. Anxiety and depression were treated first as continuous level variables, then as categorical variables using standard published cut points. Patients were then divided into four groups based on the presence of symptoms of anxiety and depression. When depression and anxiety were treated as continuous level variables, both comorbid depression and anxiety, and depression alone were significant predictors of all-cause mortality. However, when depression and anxiety were treated as categorical variables, comorbid depression and anxiety was a predictor of all-cause mortality, while anxiety and depressive symptoms considered alone were not independent predictors of the same outcome. None of those variables were significant predictors of cardiac rehospitalization outcome, regardless of whether entered as continuous or categorical level variables. The second paper is a report of a study that was conducted to (1) examine the association of stress with 6-month cardiac event-free survival; (2) examine the relationship of stress with salivary cortisol; and (3) examine the association of salivary cortisol level with 6-month cardiac event-free survival. The study sample was 81 HF patients. A prospective design was used in which patients were followed for 6 months to determine occurrence of 6-month cardiac event-free survival, defined as time to the combined endpoint of cardiac rehospitalization or all-cause death. Stress was not a significant predictor of event-free survival in HF, salivary cortisol was a significant predictor of event-free survival in the unadjusted model, but not in the adjusted model, and stress was not a significant predictor of salivary cortisol level. The final paper is a report of prospective design study that aimed to describe selfreported stress level, cognitive appraisal and coping among patients with HF, and to examine the association of cognitive appraisal and coping strategies with event-free survival based on a proposed model of HF patients’ response to stressors that been suggested according to literature to date. The study sample consisted of 88 HF patients who been followed for 6 months to determine occurrence of the combined endpoint of rehospitalization for cardiac causes or all-cause death. The study showed that stress level was associated with harm and loss cognitive appraisal. Harm/loss and threat cognitive appraisals were associated with avoidant emotional coping. Furthermore, harm/loss cognitive appraisal was a significant predictor of avoidant emotional coping and event free survival. Finally avoidant emotional coping was a significant predictor of event free survival among HF patients in the unadjusted model, but not in the adjusted model. The findings from this dissertation provided further evidence of the importance of psychosocial factors to health outcomes in HF patients. It also filled important gaps in the body of knowledge related to health outcomes among those with HF by demonstrating the need for cognitive and behavioral therapy among HF patients who negatively appraise their health condition.