Abstract 1387: Exercise Capacity as a Mediator of the Relationship Between Cardiac Performance and Quality of Life in Patients With Chronic Heart Failure
Background An estimated 5.7 million Americans are living with heart failure (HF), and 670,000 new cases are diagnosed each year. However, health-related quality of life (HRQOL) and exercise capacity have emerged as important end points in treating and managing patients with HF, but research which considers them together was limited in Taiwan. Thus, we examined whether exercise capacity mediated the relationship between different levels of cardiac performance and HRQOL in HF patients.
METHODS A convenience sample of 271 NYHA class II to IV HF patients was recruited from a medical center in northern Taiwan. The mean age of the patients was 68±14 years old; 62% were men; mean body mass index (BMI) was 28±6. The Charlson Comorbidity Index (CCI) was 2.9. Cardiac performance was measured by echocardiogram; the mean left ventricular ejection fraction (LVEF) was 40±14 %. Exercise capacity was evaluated using a 6-minute walk test (6MWT); the mean distance was 245±84 meters. The Chinese version of Minnesota Living with Heart Failure Questionnaire was used to assess disease-specific quality of life; the mean score was 47±25. We hypothesized that HRQOL is influenced by their cardiac performance, with some of this impact being mediated by the exercise capacity of HF patients, using the bio-psycho-social model as a framework.
RESULTS Controlling for gender and age, LVEF was significantly associated with distances of 6MWT and scores of HRQOL (r=.643**, −.724, respectively). Further regression analyses suggested that the 6MWT was related to HRQOL and partially mediated the LVEF. Statistical power in this study was 0.99.
CONCLUSIONS Exercise capacity causes to decrease the effects of cardiac performance on HRQOL. These findings provide support for the development of an exercise training program that facilitate or encourage increased exercise capacity for better quality of life for patients with chronic heart failure.