Health-related quality of life, functional status, and cardiac event-free survival in patients with heart failure

Background: Health-related quality of life (HRQOL), functional status, and cardiac event-free survival are outcomes used to assess the effectiveness of interventions in patients with heart failure (HF). However, the nature of the relationships among HRQOL, functional status, and cardiac event-free survival remains unclear. Objective: The purpose of this study is to examine the nature of the relationships among HRQOL, functional status, and cardiac event-free survival in patients with HF. Methods: This was a prospective, observational study of 313 patients with HF that was a secondary analysis from a registry. At baseline, patient demographic and clinical data were collected. Health-related quality of life was assessed using the Minnesota Living With Heart Failure Questionnaire and functional status was measured using the Duke Activity Status Index. Cardiac event-free survival data were obtained by patient interview, hospital database, and death certificate review. Multiple linear and Cox regressions were used to explore the relationships among HRQOL, functional status, and cardiac event-free survival while adjusting for demographic and clinical factors. Results: Participants (n = 313) were men (69%), white (79%), and aged 62 T 11 years. Mean left ventricular ejection fraction was 35% T 14%. The mean HRQOL score of 32.3 T 20.6 indicated poor HRQOL. The mean Duke Activity Status Index score of 16.2 T 12.9 indicated poor functional status. Cardiac event-free survival was significantly worse in patients who had worse HRQOL or poorer functional status. Patients who had better functional status had better HRQOL (P G .001). Health-related quality of life was not a significant predictor of cardiac event-free survival after entering functional status in the model (P = .54), demonstrating that it was a mediator of the relationship between HRQOL and outcome. Conclusion: Functional status was a mediator between HRQOL and cardiac event-free survival. These data suggest that intervention studies to improve functional status are needed.