The role of comprehensive lifestyle changes in the prevention and treatment of coronary heart disease

Chronic non-communicable diseases including coronary heart disease and type 2 diabetes have become a worldwide epidemic. As of 2002, type 2 diabetes is considered a risk equivalent to coronary heart disease (CHD) in most persons with type 2 diabetes. Both diseases share the same underlying risk factors. In the INTERHEART Study, 9 risk factors have been identified that are relevant in the etiology and prognosis of CHD, accounting for 90% of CHD risk in men and 94% in women. These risk factors are medical as well as psychological in nature and are potentially modifiable by lifestyle changes. The aim of this dissertation was to investigate the role of comprehensive lifestyle changes in the prevention and treatment of CHD. Findings of this dissertation were based on 1 completed randomized phase III trial (i.e., Lifestyle Heart Trial; LHT; n=48) and 2 health-insurance sponsored multi-site demonstration projects (phase IV; the completed Multicenter Lifestyle Demonstration Project, MLDP, n=440; the ongoing Multisite Cardiac Lifestyle Intervention Program, MCLIP, n>2000). The comprehensive lifestyle intervention that was evaluated in these stage III and IV trials consisted of a low-fat, plant-based diet, exercise, stress management, and group support sessions. Follow-ups ranged from 3 months to 5 years. The following questions were addressed in this dissertation: 1.) Can comprehensive lifestyle changes improve psychological well-being in patients with CHD for up to 5 years and are these changes associated with changes in cardiac variables and well-being in the LHT? 2.) Can patients with CHD and type 2 diabetes in the MLDP make comprehensive lifestyle changes experiencing similar improvements in coronary risk factors and quality of life when compared to CHD patients without type 2 diabetes over 1 year? 3.) Can CHD patients at risk for heart failure with a left ventricular ejection fraction (LVEF) ≤ 40% (stage B according to the guidelines of the American College of Cardiology/American Heart Association) in the MLDP make comprehensive lifestyle changes to achieve a similar improvement in medical risk factors and quality of life as those with a LVEF >40% over 1 year? 4.) Is attendance to the intervention’s social support groups in the MLDP associated with CHD patients’ adherence to the other 3 program components and with improvements in coronary risk factors and quality of life over 1 year? 5.) Can depressed patients at high risk for CHD (i.e., ≥3 coronary risk factors and/or type 2 diabetes) in the MCLIP make comprehensive lifestyle changes over 3 months and benefit in terms of reductions in depression and improvements in coronary risk factors over 3 months? Results from the LHT (phase III) demonstrated reductions in psychological distress and hostility in the experimental group (compared to controls) after 1 year. By 5 years, improvements in hostility tended to be maintained relative to the control group, but reductions in psychological distress were only reported by experimental patients with very high 5 year program adherence. Improvements in diet were related to weight reduction and to decreases in percent diameter stenosis, and improvements in stress management to decreases in percent diameter stenosis at both follow- ups. Results from the MLDP (phase IV) showed that, regardless of disease severity (i.e., CHD ± type 2 diabetes, CHD + LVEF ≤ 40% or >40%), patients were able to make comprehensive lifestyle changes, experiencing similar improvements in coronary risk factors and quality of life. In regard to patients’ social support group attendance in the MLDP, improvements in systolic blood pressure, health behaviors, and quality of life were related to social support group attendance, favoring those who attended more sessions. The associations between support group attendance to systolic blood pressure and to four quality of life (QOL) subscales (‘bodily pain’, ‘social functioning’, ‘mental health’, and the ‘mental health’ summary score) remained significant when controlling for changes in health behaviors, but dropped to a non-significant level for the QOL subscales ‘physical functioning’, ‘general health’, and ‘role-emotional’. Results from the MCLIP (phase IV) showed that initially depressed patients at risk for CHD were able to make comprehensive lifestyle changes. In addition, 73% of patients who were clinically depressed at baseline fell below the cut-off for depression on the Center for Epidemiological Scale–Depression scale (CES-D) by the 3-months follow-up. Depressed patients who became non-depressed also reduced dietary fat intake, perceived stress, and hostility and increased exercise and SF-36 Mental Component Scores more than patients who remained non-depressed and than those who remained or became depressed. In sum, this dissertation demonstrates the importance of targeting multiple health behaviors in the prevention and treatment of CHD. Medical as well as psychological risk factors can be improved by comprehensive lifestyle changes delaying the onset or the progression of CHD. Results from the LHT (phase III) suggest that lifestyle changes improve psychological well-being (e.g., depression, hostility) for at least 1 year and that an improved lifestyle is associated with benefits regarding cardiac variables over 5 years. Patients in the LHT may have psychologically adapted or habituated to their new lifestyle after 1 year. Associations between improved lifestyle and improvements in cardiac profiles, however, were still evident at 5 years. Results from the MLDP (phase IV) suggest that lifestyle changes are feasible for patients with differing disease severity. Coronary heart disease patients with diabetes and CHD patients at risk for heart failure were able to make and maintain lifestyle changes with similar improvements in clinical profiles when compared to patients who were less severely diseased. In regard to patients’ social support group attendance in the MLDP, results suggest that attendance is independently related to reductions in systolic blood pressure while improvements in quality of life are in part due to improved health behaviors that were facilitated by increased social support group attendance. Results from the MCLIP (phase IV) suggest that comprehensive lifestyle changes are feasible for initially depressed patients at risk for CHD. Seventy-three percent of patients who were clinically depressed at baseline became non- depressed by the 3-months follow-up. In these patients reductions in depression may have also contributed to improvements in health behaviors and psychological well-being.