We thank Dr. Simons and colleagues for pointing out the limits of our metaanalysis. The studies that were included in the review generally excluded patients who had an infectious source for their acute exacerbation. Thus, the results of the metaanalysis should be generalized only to cases in which an infectious etiology for the exacerbation has been carefully ruled out.1 While we agree with Dr. Simons and colleague's general comments, we have concerns regarding their use of vague and inappropriate epidemiologic terminology, which obfuscate rather than facilitate discourse on this matter. First, contrary to Dr. Simons and colleague's assertion, there was no selection bias. The selection of the studies for the present metaanalysis was transparent, inclusive, and consistent with the STROBE (Strengthening the Reporting of Observational Studies in Epidemiology) Guidelines.2 The primary studies excluded patients with an infectious etiology, which as stated previously, limits the generalizability but not the validity of the findings. Second, there was no “inadequate study sampling.” We did not sample studies; we included all published studies that met the a priori inclusion and exclusion criteria. Third, there was no “exclusion of patient categories.” We did not exclude patients or studies based on categories such as age, sex, race, lung function, or any other variables.