Study Limitations:
There are a few notable limitations to our study. First, we relied on self-reported rather than clinical data, so the associations of substance use with health outcomes and CFTR modulators may be under- or over-reported. Second, the survey was administered through online channels utilizing social media platforms, a method susceptible to infiltration of fraudulent responses. We addressed this by including internal validity questions and using CAPTCHA (Completely Automated Public Turing test to tell Computers and Humans Apart) feature. We carefully reviewed the validity questions and removed suspected automated responses by bots from the study. Third, subjects recruited via social media may represent pwCF who have an interest in these substances, which would potentially overestimate the prevalence, however, we found that the prevalence was not significantly skewed toward current use relative to non-use. The survey was also not translated into Spanish, limiting the participation of a subset of potential subjects, and our findings’ generalizability; therefore, our results should not preclude discussions around substance use in all pwCF.