Test-Retest Reliability of the Coronary Heart Disease Damp Phlegm and Blood Stasis Pattern Questionnaire: Results from a Multicenter Clinical Trial

BACKGROUND: Damp phlegm and blood stasis pattern (DPBSP) is the main pattern in coronary heart disease (CHD) patients. To quantify and standardize the diagnosis of DPBSP, questionnaires are usually administered. The CHD Damp Phlegm and Blood Stasis Pattern Questionnaire (CHD-DPBSPQ) is the standard metric for measuring CHD-DPBSP signs and symptoms in practice and clinical research. The CHD-DPBSPQ has moderate diagnostic efficiency, as evidenced by its receiver operating characteristic curves. Furthermore, and high reliability and validity have been shown in some studies but not in a multicenter clinical trial. Our purpose was to evaluate the test-retest reliability of a proprietary CHD-DPBSPQ. METHODS: The CHD-DPBSPQ uses a standard procedure for measuring symptoms. The (interrater) reliability and validity of this questionnaire have been previously studied. Here, we evaluated the test interval and weighted kappa value of items of test-retest (intrarater) reliability of the CHD-DPBSPQ. The test-retest reliability was evaluated by the intraclass correlation coefficient (ICC) for the total CHD-DPBSPQ score and the phlegm domain and blood stasis domain scores. Weighted kappa statistics were calculated for the individual CHD-DPBSPQ items. RESULTS: Using the CHD-DPBSPQ, 79 patients with late-stage CHD who were participating in a multicenter clinical trial were assessed twice. The ICCs for the CHD-DPBSPQ score were as follows: 0.827 for the total CHD-DPBSPQ, 0.778 for the phlegm domain score, and 0.828 for the blood stasis domain score. The reliability was slightly better in patients whose test interval was ≤14 days. The weighted kappa values of individual items showed moderate consistency. CONCLUSIONS: The CHD-DPBSPQ was found to have excellent test-retest reliability in this sample of patients.