Development and validation of the pulmonary tuberculosis scale of the system of Quality of Life Instruments for Chronic Diseases (QLICD-PT)

BACKGROUND: Generic assessments are less responsive to subtle changes due to specific diseases, making it challenging to fully understand the impact of pulmonary tuberculosis (TB) on patient’s quality of life (QOL). METHODS: We applied programmed decision procedures and theories on instrument development to develop the scale. Two hundred patients with pulmonary TB participated in measuring QOL three times before and after treatments. We assessed the validity, reliability, and responsiveness of QLICD-PT using correlation analysis, factor analysis, multi-trait scaling analysis, randomized block analyses of variance with Least Significant Difference post-hoc tests. RESULTS: We composed QLICD-PT with 3 domains (28 items) for general QOL and 1 pulmonary TB specific domain (12 items). Correlation and factor analysis confirmed good structure validity and criterion-related validity when using Chinese version of the Medical Outcomes Short-Form Health Survey (SF-36) as a criterion. The internal consistency of α values were higher than 0.70. The score changes after treatment were of statistical significance for the overall scale, physical domain and specific domain with effect size ranging from 0.32 to 0.72. No floor effects but small ceiling effects were observed at domain level. CONCLUSIONS: As the first pulmonary TB-specific QOL scale developed by a module approach in Chinese, QLICD-PT has an acceptable degree of validity, reliability and responsiveness, and can be used to measure the life quality of PT patients specifically and sufficiently.