Comparable performance of the Kansas City Cardiomyopathy Questionnaire in patients with heart failure with preserved and reduced ejection fraction

Abstract

Background: Despite the growing epidemic of heart failure with preserved ejection fraction (HFpEF), no valid measure of patients' health status (symptoms, function, and quality of life) exists. We evaluated the Kansas City Cardiomyopathy Questionnaire (KCCQ), a validated measure of HF with reduced EF, in patients with HFpEF.

Methods and results: Using a prospective HF registry, we dichotomized patients into HF with reduced EF (EF≤ 40) and HFpEF (EF≥50). The associations between New York Heart Association class, a commonly used criterion standard, and KCCQ Overall Summary and Total Symptom domains were evaluated using Spearman correlations and 2-way ANOVA with differences between patients with HF with reduced EF and HFpEF tested with interaction terms. Predictive validity of the KCCQ Overall Summary scores was assessed with Kaplan-Meier curves for death and all-cause hospitalization. Covariate adjustment was made using Cox proportional hazards models. Internal reliability was assessed with Cronbach's α. Among 849 patients, 200 (24%) had HFpEF. KCCQ summary scores were strongly associated with New York Heart Association class in both patients with HFpEF (r=-0.62; P<0.001) and HF with reduced EF (r=-0.55; P=0.27 for interaction). One-year event-free rates by KCCQ category among patients with HFpEF were 0 to 25=13.8%, 26 to 50=59.1%, 51 to 75=73.8%, and 76 to 100=77.8% (log rank P<0.001), with no significant interaction by EF (P=0.37). The KCCQ domains demonstrated high internal consistency among patients with HFpEF (Cronbach's α=0.96 for overall summary and ≥0.69 in all subdomains).

Conclusions: Among patients with HFpEF, the KCCQ seems to be a valid and reliable measure of health status and offers excellent prognostic ability. Future studies should extend and replicate our findings, including the establishment of its responsiveness to clinical change.

Keywords: health status; heart failure, diastolic; quality of life.

Figure 1

KCCQ Summary Score Association with NYHA Class in HFrEF and HFpEF

Figure 2

Kaplan-Meier Curves for Death or Hospitalization Panel A: Entire study cohort, HFrEF and HFpEF, Panel B: In HFpEF (EF>50%)

Figure 3

Cox Proportional Hazards Model for Death and Hospitalization in HFpEF and HFrEF Reference levels: race = White, KCCQ = 76–100.