Relationships between clinical assessments and patients' perceptions of the effects of heart failure on their quality of life

Abstract

Background: Hypothetically, most of the effects of heart failure on quality of life might be attributed to symptoms produced by the pathology. Relationships between measures of these concepts need to be quantified to test this conceptual model.

Methods and results: Measurements of heart failure pathology and symptoms and quality of life as measured by the Minnesota Living with Heart Failure (MLHF) questionnaire at the 4-month visit in the Valsartan Heart Failure Trial were analyzed. Correlation and regression analyses corrected for estimated reliability of measurements were used to quantify relationships. The percentage of variance in dependent variables that was related to explanatory variables was summarized by the coefficient of determination (100 xR(2)) from regression models. Dyspnea at rest, dyspnea on exertion, paroxysmal nocturnal dyspnea, orthopnea, fatigue, and New York Heart Association class were significantly related to MLHF scores. Combined, these symptoms explained 41% of the variation in MLHF scores. Controlling for symptoms, age explained an additional 4.5% of the variation in MLHF scores, whereas race, gender, and available comorbidities each explained <1%. Pathologic measures including ejection fraction, B-type natriuretic peptide, jugular venous distension, rales, peripheral edema, systolic blood pressure, creatinine, and hemoglobin were not strongly related to symptom assessments (combined R(2) = 17%) or MLHF scores (combined R(2) = 7%).

Conclusion: Symptoms of heart failure explain a substantial proportion of the variation in the effects of heart failure on patients' quality of life as measured by the MLHF score. The effects of heart failure on quality of life can vary with age independently of symptoms. Pathologic measures of heart failure including some well-known correlates of the risk of hospitalization and death are not strongly related to symptoms or quality of life. Further studies are needed to understand the relationships between heart failure pathology and symptoms and to identify determinants of the effects of heart failure on patients' quality of life that were not related to symptoms.