For each subset of items, we then calculated a short-version domain score following the KCCQ scoring methodology and examined how closely the short score tracked with the corresponding full-version score.
We used Lin’s concordance correlation coefficient, which measures the agreement between 2 variables; concordance values range from −1 (perfect negative agreement) to 1 (perfect positive agreement), with 0 denoting no agreement.
Using these studies, we derived and validated the short KCCQ within 3 distinct clinical settings: (1) stable HF, (2) outpatient HF clinic visits, and (3) acute HF recovery (1 week after hospitalization for decompensated HF).
Within each setting, data were split randomly into 2 50% samples, one for derivation (ie, item selection) and one for validation of the final short-version scores.
For the physical limitation domain, which covers low, moderate, and high intensity activities (2 items each), we sought to preserve the range of activities represented by selecting one item from each level of exertional demand, resulting in 8 possible subsets.
For the quality of life and social limitation domains, we considered all possible subsets of items (omitting the “intimate relationships” item from the latter domain as a result of high nonresponse rates), yielding 6 and 7 subsets, respectively.
Once the final set of items was identified, scores for each of the 4 domains were calculated using methodology analogous to that of the full KCCQ, so that scores ranged from 0 to 100 for each domain.Quantifying patients’ perspectives about the degree to which their heart failure (HF) impacts their health status (their symptoms, function, and quality of life) is becoming an increasingly important outcome in clinical trials, quality assessment, and clinical care.Transitioning PROs from outcomes in clinical trials, where the studies pay for additional data collection, to routine clinical care requires that the measures be short and feasible to collect, while also retaining the important psychometric properties of validity, reliability, sensitivity to clinical change, prognostic importance, and interpretability. Editorial see p 460Given the importance of being able to accurately and objectively assess patients’ health status and prognosis using a low-cost, noninvasive strategy, we sought to develop a shorter version of the KCCQ that preserves the psychometric and prognostic properties of the original instrument.We also excluded the 3 Symptom Burden items, which ask patients how bothersome their symptoms (edema, fatigue, dyspnea) are because they were each highly correlated with their corresponding Symptom Frequency item (=0.78–0.87) and had less response variability.For the Symptom Frequency domain, we chose to retain all 4 items to fully represent the spectrum of HF symptoms.