Abstract
Objective: to assess the psychometrics properties of the COPD assessment test (CAT) in a randomized trial comparing the face-to-face interview with the telephone interview.
Methods: a randomized study was conducted at two teaching hospitals in Fortaleza-Brazil. Patients were randomly assigned to answer the CAT questionnaire either by a face-to-face interview (FFI) or a telephone interview (TI). The two groups were assessed for internal consistency reliability, cross-sectional validity and test-retest reliability. All patients performed spirometry and answered the modified medical research council dyspnoea scale (mMRC) and the St George’s respiratory questionnaire (SGRQ).
Results: For both administration formats, we found good internal consistency reliability (Crohnbach's alpha between 0.77 and 0.89 for the TI and FFI respectively). In general, moderate-to-high correlations of CAT with SGRQ were observed, independent of the format of administration. For the test-retest reliability, the intraclass correlation coefficients were very similar for both FFI and TI group: 0,96 (95%CI 0,93-0,97) vs 0,98 (95%CI 0,96-0,98) respectively.
Conclusion: This study demonstrated that the CAT questionnaire administration either by a face-to-face or telephone interview present moderate to high psychometrics properties. This provides support for the use of both modes of questionnaire administration.
- © 2013 ERS