SOCIAL SUPPORT, MARRIAGE AND PSYCHOBIOLOGICAL PATHWAYS TO ADJUSTMENT FOLLOWING ACUTE CORONARY SYNDROME Gemma Hutton Department of Epidemiology and Public Health University College London 2013 Thesis submitted to University College London for the degree of Doctor of Philosophy I, Gemma Hutton, confirm that the work presented in this thesis is my own. Where information has been derived from other sources, I confirm that this has been indicated in the thesis. Signature ……………………………….. Date …………… ABSTRACT The key aims of this thesis were to investigate the role of social support and marriage in adjustment and recovery in coronary heart disease (CHD). Declining death rates in CHD due to medical and surgical advances combined with increasing prevalence rates have contributed to a large and steadily growing population of chronic CHD patients, many of whom have suffered an acute cardiac event. In the context of this population, there is considerable need to determine factors that improve both adjustment and prognosis. Aspects of social support and marriage have been robustly associated with morbidity and mortality in CHD. Exploration of the potential psychological and biological pathways that link these factors forms the core of this thesis. Data from two separate studies are presented with the majority of analyses originating from data gathered in the Tracking Recovery after Acute Coronary Events (TRACE) study, a longitudinal study exploring diverse correlates of adjustment and recovery in 298 ACS patients. Associations between social support, marital satisfaction, distress, quality of life and HRV among ACS patients followed up from hospital admission to 12 months following discharge are presented. Data were also derived from a second study which explored psychobiological factors in a sample of 88 suspected coronary artery disease (CAD) patients and the analysis focused on marital influence on HRV. The overall thesis objective was to identify significant relationships between social and marital support, and various psychobiological factors that may contribute to adjustment and, ultimately, influence CHD prognosis. 3 TABLE OF CONTENTS Abstract ………………………………………………………………………. 3 Table of contents ………………………………………………………………………. 4 List of figures ………………………………………………………………………. 15 List of tables ………………………………………………………………………. 17 Publications ………………………………………………………………………. 24 Acknowledgements ………………………………………………………………………. 26 CHAPTER 1. Literature review: Cardiovascular disease and psychological risk factors 27 1.1 Overview of cardiovascular disease 27 1.2 Psychological factors in cardiovascular disease 29 1.2.1 The role of depression and anxiety in the aetiology of CHD 29 1.2.2 The role of depression in prognosis after ACS 29 1.2.3 The role of anxiety in prognosis after ACS 30 1.3 Pathways between psychological factors and prognosis after ACS 41 1.3.1 Distress and increased cardiac risk factors 42 1.3.2 Distress and biological mechanisms of risk 45 1.4 Chapter summary 48 CHAPTER 2. Literature review: Social support, marriage and CHD 49 2.1 Social support 49 2.1.1 Structural social support 49 2.1.2 Functional social support 52 2.1.3 Marital status and satisfaction 55 2.2 Social support, marriage and health 58 2.3 Theoretical models of social support 66 2.3.1 Buffering effects 66 2.3.2 Direct effects 67 2.4 Theoretical models of marriage 71 4 2.4.1 Selection effects 71 2.4.2 Protection effects 74 2.4.3 Summary of theoretical models 77 2.5 Social support , CHD and ACS 78 2.5.1 Social support, marriage and aetiology of CHD 78 2.5.2 Social support and prognosis of ACS 81 2.5.3 Marital status, marital satisfaction and prognosis of ACS 83 2.6 Pathways between social support, marriage and ACS prognosis 85 2.6.1 Behavioural pathways 86 2.6.1.1 Health behaviour 86 2.6.1.2 Adherence to medication 87 2.6.1.3 Adherence to cardiac rehabilitation 88 2.6.2 Psychological pathways 89 2.6.2.1 Depression 89 2.6.2.2 Anxiety 93 2.6.3 Quality of life 96 2.6.4 Biological pathways 100 2.6.4.1 Cardiovascular functioning and ACS prognosis 100 2.6.4.2 Other potential biological pathways 105 2.7 Chapter summary 107 CHAPTER 3. Heart rate variability and marital status study 108 3.1 Introduction 108 3.2 Methodology 111 3.2.1 Participants 111 3.2.2 Procedure 111 3.2.3 Measures 112 3.2.3.1 Demographic and anthropometric measures 112 3.2.3.2 Psychological measures 112 3.2.3.2.1 Beck depression Inventory (BDI) 112 5 3.2.3.2.2 Hospital Anxiety and Depression Scale (HADS) 113 3.2.3.2.3 Medical Outcome Short Form-36 (SF-36) 113 3.2.3.3 Clinical measures 113 3.2.3.4 Heart rate variability measurement 114 3.3 Statistical analyses 115 3.3.1 My role in the study 115 3.4 Results 115 3.5 Discussion 119 CHAPTER 4. TRACE (Tracking Recovery After Coronary Events) Methodology 125 4.1 Design 125 4.2 Hypotheses 125 4.2.1 Structural and functional social support as predictors of short and long term 125 psychological response and adjustment following ACS 4.2.2 The relationship between social support and heart rate variability (HRV) in 127 post ACS patients 4.2.3 Marital status and satisfaction as predictors of short and long term 127 psychological response and adjustment following ACS 4.2.4 The relationship between marital status, marital satisfaction and heart rate 128 variability (HRV) in post ACS patients 4.3 Participants 129 4.4 Procedure 132 4.4.1 Time 1 (in hospital) assessment 132 4.4.2 Time 2 (post discharge) assessment 132 4.4.3 Time 3 (6 month) follow up assessment 133 4.4.4 Time 4 (12 month) follow up assessment 133 4.4.5 My role in study design, data collection and analysis 134 4.5.Measures 134 4.5.1 Time 1 measures 135 4.5.1.1 Socio-demographic information 135 6 4.5.1.2 Clinical data 136 4.5.2 Time 2 measures 136 4.5.2.1 Psychosocial measures 136 4.5.2.1.1 Beck Depression Inventory (BDI) 136 4.5.2.1.2 Hospital Anxiety and Depression Scale (HADS) 137 4.5.2.1.3 Marital satisfaction 137 4.5.2.1.4 Social Network Index (SNI) 138 4.5.2.1.5 ENRICHD Social Support Inventory (ESSI) 138 4.5.2.1.6 Medical Outcome Short Form (SF-12) Quality of Life 139 4.5.2.2 Health Behaviours 140 4.6.2.2.1 Diet 140 4.6.2.2.2 Physical activity 140 4.6.2.2.3 Smoking 141 4.6.2.2.4 Alcohol consumption 141 4.6.2.2.5 Medication adherence 141 4.5.2.3 Heart Rate Variability 142 4.6 Time 3 Measures 143 4.6.1 Psychosocial measures 143 4.6.2 Health behaviour 143 4.7 Time 4 Measures 143 4.7.1 Psychosocial measures 143 4.7.1 Health behaviour 143 4.8 Data storage 143 4.9 Statistical analysis 144 CHAPTER 5. TRACE study results Part 1 147 5.1 Patient characteristics Time 1 – Time 4 147 5.1.1 Baseline (Time 1) characteristics 147 5.1.2 Time 2 characteristics 148 5.1.3 Time 3 characteristics 149 7 5.1.4 Time 4 characteristics 150 5.2 Social support at Time 2, 3 and 4 154 5.2.1 Analytic dataset 154 5.2.2 Social support measures 154 5.2.2.1 Structural social support 154 5.2.2.2 Functional social support 156 5.3 The influence of demographic factors on social support 157 5.3.1 Demographic influences on functional and structural social support at Time 2 158 5.3.2 Demographic influences on functional social support at Time 3 159 5.3.3 Demographic influences on functional social support at Time 4 160 5.4 Summary: Social support at Time 2, 3 and 4 161 CHAPTER 6. TRACE study results Part 2 162 6.1 Psychological distress at Time 2, 3 and 4 162 6.1.1 Analytic dataset 162 6.1.2 Psychological distress after ACS at Time 2 162 6.1.2.1 The influence of demographic and clinical factors on psychological 165 response at Time 2 6.1.2.2 Summary: Psychological distress at Time 2 170 6.1.3 Psychological distress after ACS at Time 3 171 6.1.3.1 The influence of demographic and clinical factors on psychological 173 distress at Time 3 6.1.3.2 Summary: Psychological distress at Time 3 179 6.1.4 Psychological distress to ACS at Time 4 180 6.1.4.1 Summary: Psychological distress at Time 4 180 6.1.5 Summary: Psychological distress to ACS 181 6.2 Functional and structural social support as correlates and predictors of post ACS psychological distress 181 6.2.1 Introduction 181 6.2.2 Data analysis 182 8 6.2.3 Functional social support and psychological distress at Time 2 182 6.2.3.1 Summary 187 6.2.4 Structural social support and psychological distress at Time 2 188 6.2.4.1 Summary 192 6.2.5 Social support and psychological distress at Time 3 192 6.2.5.1 Cross sectional analysis 192 6.2.5.2 Longitudinal analysis T2 functional social support and T3 198 psychological distress 6.2.5.3 Longitudinal analysis T2 structural social support and T3 205 psychological distress 6.2.6 Social support and psychological distress at Time 4 209 6.2.6.1 Cross sectional analysis 209 6.2.6.2 Longitudinal analysis T2 functional social support and T4 216 psychological distress 6.2.6.3 Longitudinal analysis T2 structural social support and T4 222 psychological distress 6.2.7 Overall summary: Social support and psychological distress after ACS 226 6.3 Chapter discussion 228 6.3.1 Psychological distress after ACS 228 6.3.2 Social support and psychological distress after ACS 231 6.3.3 Chapter summary 234 CHAPTER 7. TRACE study results Part 3 & 4 235 7.1 Quality of life at Time 2, 3 and 4 235 7.1.1 Analytic dataset 235 7.1.2 Quality of life at Time 2 235 7.1.3 Quality of life at Time 3 239 7.1.4 Quality of life at Time 4 244 7.1.5 Summary: Quality of life after ACS 244 7.2 Functional and structural social support as correlates and predictors of post ACS quality 245 9 of life 7.2.1 Introduction 245 7.2.2 Data analysis 245 7.2.3 Social support and quality of life at Time 2 246 7.2.3.1 Functional social support and quality of life at Time 2 246 7.2.3.2 Structural social support and quality of life at Time 2 248 7.2.4 Social support and quality of life at Time 3 250 7.2.4.1 Cross sectional analysis 250 7.2.4.2 Longitudinal analysis T2 functional social support and T3 quality of 253 life 7.2.4.3 Longitudinal analysis T2 structural social support and T3 quality of 256 life 7.2.5 Social support and quality of life at Time 4 258 7.2.5.1 Cross sectional analysis 258 7.2.5.2 Longitudinal analysis T2 functional social support and T4 quality of 262 life 7.2.5.3 Longitudinal analysis T2 structural social support and T4 quality of 265 life 7.2.6 Overall summary: Social support and quality of life after ACS 267 7.3 Part 4: The role of social support in heart rate variability after ACS 270 7.3.1 Analytic dataset 270 7.3.2 HRV at Time 2 270 7.3.3 Social support and HRV at Time 2 270 7.3.3.1 Functional social support and HRV at Time 2 271 7.3.3.2 Structural social support and HRV at Time 2 273 7.2.4 Summary: Social support and HRV after ACS 275 7.4 Chapter discussion 275 7.4.1 Quality of life after ACS 275 7.4.2 Social support and quality of life after ACS 276 10