Test-retest reliability of EORTC QLQ FA 13 instrument for fatigue assessment in oncological patients

Abstract Objective To verify the test-retest stability of the EORTC QLQ FA 13 instrument in the Brazilian Portuguese version through the semantic equivalence process, including the equivalence phase of measurement that covers psychometric studies. Methods The instrument was applied in 163 patients undergoing cancer treatment in the clinical and surgical infirmaries of a highly complex hospitallocated in the city of Rio de Janeiro between March 2015 and October 2016 through a questionnaire applied in an individual interview. In order to test the suitability of the measurement process, participants were requested to answer the questionnaire a second time after and interval of 7 to 15 days. Results Among participantsed, 50 (30.67%) also adhered to retest. There was good understanding of the instrument at the test stage. The responses were stable, and the estimates of test-retest reliability varied from good to excellent (kappa = 0.66 to 0.80), either for items or for scale dimensions. Conclusion The present study and other previous steps of reliability of the instrument suggest a high stability of the information collected, which makes its applicability in the Brazilian population useful for improving the quality of care of cancer patients.