Comparison Between the Kansas City Cardiomyopathy Questionnaire and New York Heart Association in Assessing Functional Capacity and Clinical Outcomes

Objective The Kansas City Cardiomyopathy Questionnaire (KCCQ) has emerged as a patient-centered heart failure–specific health status measure. It currently lacks routine and widespread use in clinical practice and trials. The purpose of this study was to examine the correlation between KCCQ and cardiopulmonary exercise testing (CPET) parameters and clinical outcomes, compared with the New York Heart Association functional classification (NYHA). Methods and Results We performed a single-centered observational analysis of 432 patients who presented to the Heart Failure Department, completed the KCCQ, and underwent CPET. The 1-year clinical outcome assessed was a composite of mortality, heart failure hospitalization, and need for heart transplantation or left ventricular assist device. In the KCCQ, the physical limitation domain had a correlation with peak VO2 similar to NYHA (r = 0.48; P < .001; and r = −0.48; P < .001; respectively), and slightly better correlation with ventilatory threshold (r = 0.42; P < .001; and r = −0.40; P < .001; respectively). According to model validation, the KCCQ physical limitation domain and NYHA were similar predictors of peak VO2 (r2 = 0.229; and r2 = 0.227; respectively). KCCQ predicted the specified 1-year clinical outcome (hazard ratio 0.75, 95% confidence interval 0.69–0.82; P < .001) and provided incremental predictive ability when added to a model that included NYHA, with a net reclassification index of 76.1% (P < .001). Conclusions KCCQ and NYHA provide similar assessment of functional capacity. KCCQ predicts 1-year clinical outcomes, providing incremental value over NYHA. These findings support its routine use in clinical care, as well as its potential to serve as a measure in clinical trials.