Predictors of the 6-minute walk test in patients with chronic heart failure

Abstract

Introduction: The six-minute walk test (6-MWT) is a simple, inexpensive measure used to evaluate functional capacity in heart failure (HF). The purpose of this study was to identify routinely made predictors of 6-MWT performance and develop a prediction equation in the HF population. Methods: Seventy-one patients with HF (82% males and 18% females; mean age 76 ± 9 years), enrolled in a chronic disease assessment programme and completed the standardised 6-MWT. Measurements of stature, weight, step length, ventricular function and New York Heart Association (NYHA) functional class were recorded. Results: Mean distance walked was 305 ± 123 metres. Age and stature were the only variables which correlated significantly with test performance (r1=-0.422, r2=0.351, respectively, for p<0.005). Gender-specific regression equations using anthropometric data explained 40% and 52% of the variance in 6-MWT performance in males and females, respectively. Univariate multinomial logistic regression analysis showed that BMI ≥25 kg/m2 (OR = 12.8, 95% CI = 1.46–112) and age ≥75 years (OR = 4.9, 95% CI = 1.3–18.8) were independent predictors of poor performance (<300 metres). Conclusion: Clinicians should take account of age, stature and BMI when interpreting results of the 6-MWT in patients with HF.