Several mechanisms for establishing standards for interpreting scores are available.

Several mechanisms for establishing standards for interpreting scores are available.

One is to examine the prognostic significance of KCCQ scores and the other is to benchmark score changes against clinical assessments of change. To facilitate the interpretation of cross-sectional KCCQ scores, 1,516 patients assessed 3 months after a myocardial infarction complicated by heart failure were followed for 1 year survival and heart failure hospitalization. This figure describes the Kaplan-Meier curves for this study:

kccq-3mo.jpg

To interpret changes in KCCQ scores, a cohort of 460 patients from 13 centers were followed for 6±2 weeks at which point physicians assessed their clinical change (blinded to KCCQ scores). Among these patients, the magnitude and direction of change was as follows: deterioration, n=5 (1); moderate deterioration, n=13 (3); deterioration, n=35 (7); no change, n=320 (67); improvement, n=65 (14); moderate improvement, n=34 (7); and improvement, n=4 (1). The KCCQ change scores were exquisitely reflective of clinical changes in heart failure both in terms of its directionality (improvement versus deterioration) and proportion-al-ity of change (magnitude) — as revealed in this figure:

For patients experiencing , moderate and deteriorations in their condition, KCCQ Overall Summary scores decreased by -24.9±15.8, -16.8±13.8 and -5.4±10.8 points. For those with no, , moderate and improvements in their heart failure, the KCCQ scores improved by 1.3±11.8, 5.7±16.1, 10.7±16.2 and 22.3±15.0 points. The mean change in KCCQ scores was significantly different for all categories of change compared to stable patients. Even those with clinical deteriorations or improvements (-5.3±11 for deterioration vs. 1.3±12 for no change, p=0.002 and +5.7±16 for improvement, p=0.01). This suggests that a mean difference over time of 5 points on the KCCQ Overall Summary Scale reflects a clinically significant change in heart failure status.

An alternative approach to interpreting clinical changes is to appreciate the prognostic significance of changes in scores. In a cohort 659 subjects assessed 3 and 6 months after an MI complicated by CHF, those patients whose KCCQ overall summary scores declined by ≥ 10 points had a 107

increased risk of dying or being hospitalized over the next 3 months (event rate = 11.4% vs. 5.5,p<0.001). By one year after the last KCCQ assessment, a 94 increased relative risk of cardiovascular death/hospitalization was observed (27.7% vs. 14.3%, p<0.001).

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These data suggest that a 10 point decline in KCCQ scores has important prognostic significance.

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