December 28, 2007Open Access
Validity, reliability, and responsiveness of the Kansas City Cardiomyopathy Questionnaire in anemic heart failure patients
Key Result
The Kansas City Cardiomyopathy Questionnaire demonstrated similar psychometric properties in heart failure patients with and without anemia, including comparable test-retest reliability (p=0.14).
Study Design
Type
Cohort (n=811)
Multicenter
Yes
Structured PICO
Does the Kansas City Cardiomyopathy Questionnaire (KCCQ) maintain its validity, reliability, and responsiveness in heart failure patients with anemia compared to those without?
P
Population
811 heart failure outpatients from 58 U.S. centers, including 268 (33%) with anemia (hemoglobin <13 g/dl for men, <12 g/dl for women). Mean age 67 (anemic) and 63 (nonanemic).
I
Intervention
Kansas City Cardiomyopathy Questionnaire (KCCQ) administration
C
Comparator
Performance in non-anemic heart failure patients
O
Outcome
Psychometric properties of the KCCQ (construct validity, internal consistency, test-retest reliability, and responsiveness)patient reported
The KCCQ is a valid, reliable, and responsive measure of health status in heart failure patients regardless of the presence of anemia, supporting its use in clinical trials.
Main Result
Absolute Event Rate: -2.8% vs -0.5%
p-value: p=0.14
Limitations
- Absence of a criterion standard for a patient-centered outcome such as health status
- Assessments of change in HF came from a global patient-reported estimate of change
- 12% of patients were lost to follow-up, which may introduce potential bias
Abstract
BACKGROUND: While generic health status measures quantify the impact of all patients' diseases on their health-related quality of life, disease specific measures focus on only one of the many conditions that a patient may have. If a patient has two diseases with similar clinical manifestations, they may respond differently to a disease-specific instrument if one of their conditions improves while the other worsens or remains stable, thus undermining the instruments in that patient population. We sought empirical evidence of the reliability and validity (including responsiveness) of the Kansas City Cardiomyopathy Questionnaire (KCCQ), a disease-specific measure for heart failure (HF), among HF patients with and without anemia, a condition that has similar symptoms to HF. METHODS: This work used a prospective cohort study of 811 HF outpatients from 58 U.S. centers with a baseline assessment of anemia of whom 698 were followed for 3 months with serial health status measures. RESULTS: Among participants, 268 (33%) were anemic. The construct validity of the KCCQ was supported by showing similar correlations with the New York Heart Association (NYHA) classification in patients with and without anemia (P value for interaction = 0.38). The internal consistency (Cronbach's alpha = 0.92 and 0.93 for anemic and non-anemic patients, respectively) and test-retest reliability (mean 3-month change scores in stable patients = -2.8 SD = 1.4 and -0.5 SD = 0.8, P = 0.14) were similar. Estimates of responsiveness were also similar. CONCLUSION: This study provides empirical evidence that the psychometric properties of the KCCQ are similar in patients with or without anemia, a potentially confounding clinical condition in patients with heart failure.