Gilead Sciences has investigated the use of the Respiratory Domain of the Quality of Life Questionnaire-Bronchiectasis (QOL-B) in evaluating patients taking inhaled aztreonam, a drug used to treat cystic fibrosis lung infections.
Gilead researchers were primarily interested in how the QOL-B would perform as an outcome measurement for bronchiectasis treatment. To test for reliability, the researchers gave the QOL-B to enrolled patients twice during the pre-study evaluation, when no changes or treatments were given. According to the study results, the QOL-B showed an Intraclass Correlation Coefficient (ICC) of 0.80, which is higher than the threshold of 0.70 that indicates strong reliability. In other words, when the patients were re-tested after initial testing, their answers changed minimally.