Defining changes in physical limitation from the patient perspective: insights from the VITALITY-HFpEF randomized trial.

Aims: Clinically important thresholds in patient-reported outcomes measures like the Kansas City Cardiomyopathy Questionnaire (KCCQ) have not been defined for patients with heart failure and preserved ejection fraction (HFpEF). The aim of this study was to estimate meaningful thresholds for improvement or worsening in the KCCQ physical limitation score (PLS) in patients with HFpEF.

Methods And Results: In this pre-specified analysis from VITALITY-HFpEF, anchor- and distribution-based approaches were used to estimate thresholds for improvement or worsening in the KCCQ-PLS using Patient Global Impression of Change (PGIC) as an anchor. The KCCQ-PLS contains six elements, with each increment in response resulting in a change of 4.17 points when converted to a 0-100 scale. The mean change in KCCQ-PLS from baseline to week 12 was calculated for each PGIC group to estimate a meaningful within-patient change. Of 789 patients enrolled, 698 had complete KCCQ-PLS and PGIC data at week 12. The mean (± standard deviation) changes in KCCQ-PLS corresponding to PGIC changes of 'a little better', 'better', and 'much better' were 5.7 ± 18.6, 11.6 ± 19.3, and 18.4 ± 25.3 points, respectively. The scores of patients who responded 'a little better' (n = 177) overlapped substantially with those who reported 'no change' (n = 193; mean change 2.8 ± 18.9). The mean change in KCCQ-PLS for patients responding 'a little worse' (n = 32) was -2.6 ± 18.0 points. The threshold for meaningful within-patient change in KCCQ-PLS based on distribution-based analyses was 12.3 points. Using area under the curve (AUC) analyses of KCCQ-PLS, the sensitivity and specificity of a 4.17-point change were 0.61 and 0.57, for an 8.33-point change they were 0.49 and 0.64, and for a 12.5-point change they were 0.44 and 0.72 for being at least a little better on the PGIC (AUC = 0.54).

Conclusion: In the VITALITY-HFpEF trial, a change in KCCQ-PLS of ≥8.33 points (corresponding to an improvement in ≥2 response categories of KCCQ-PLS) may represent the minimal clinically important difference for improvement and a change of ≤ -4.17 points (corresponding to a worsening in ≥1 response category of KCCQ-PLS) may suggest deterioration in patients with HFpEF.