Translation, cross-cultural adaptation, and validation of the Lung Transplant Quality of Life (LT-QOL) questionnaire for use in adult patients after lung transplantation into Portuguese Brazilian

Abstract

OBJECTIVE: To translate, cross-culturally adapt, and validate the Lung Transplant Quality of Life questionnaire into Brazilian Portuguese. METHODS: This observational study enrolled 50 participants. Translation and cross-cultural adaptation were conducted in accordance with established guidelines for self-report measures and the Consensus-based Standards for the Selection of Health Measurement Instruments (COSMIN). The measurement properties assessed included internal consistency, agreement, intra-rater reliability, and convergent validity. Convergent validity was evaluated by comparing the Lung Transplant Quality of Life with the Short Form Health Survey (SF-36) and the Saint George's Respiratory Questionnaire. RESULTS: The Lung Transplant Quality of Life showed adequate internal consistency (Cronbach's alpha=0.86) and excellent intra-rater reliability (intraclass correlation coefficient=0.93). Agreement analysis yielded a standard error of measurement of 8.72. Bland-Altman analysis revealed low mean differences (0.8) between Lung Transplant Quality of Life scores and acceptable limits of agreement (95%CI=-16.9-15.3). Spearman's correlation showed excellent convergent validity with the SF-36 and good validity with the Saint George's Respiratory Questionnaire in both test and retest phases. CONCLUSION: The Brazilian Portuguese version of the Lung Transplant Quality of Life is a valid and reliable instrument for assessing health-related quality of life in lung transplant patients. Further research is warranted to develop a shorter version while preserving its measurement properties.