Prognostic value of the 6 min walk test and self-perceived symptom severity in older patients with chronic heart failure

Abstract

Background The 6 min walk test (6-MWT) is a simple and popular test for evaluating functional status in patients with chronic heart failure (CHF). However, the prognostic value of the 6-MWT in a large, representative sample of CHF patients, and in patients with different degrees of left ventricular systolic dysfunction (LVSD) remains unclear. Methods and results Of an initial population of 1592 patients, 212 died representing a crude death rate of 13.3%. In surviving patients, the median time to follow-up period was 36.6 months [inter-quartile range (IQR) 28–45 months]. Five variables remained independent predictors of all-cause mortality; decreasing 6-MWT distance, self-perceived signs of breathlessness at night (SOBAN), beta-blocker usage, elevated log NT-proBNP, and reduced haemoglobin concentration. We also dichotomized our analysis by LVSD status (≤mild LVSD or >mild LVSD). For patients with >mild LVSD, 6-MWT remained an important prognostic indicator but not in patients with ≤mild LVSD. Conclusion The 6-MWT is an important independent predictor of mortality in CHF patients, and this was especially evident in patients with >mild LVSD. The 6-MWT provides little prognostic utility in patients with ≤mild LVSD. While log NT-proBNP was the most potent independent predictor, an additive prognostic effect was evident with the additional selection of 6-MWT. Patients' self-perceived symptoms, especially SOBAN was an independent predictor of mortality in our patients.