Endoscopic grading systems for nasal polyps: are we comparing apples to oranges?

Endoscopic grading of nasal polyps (NP) is typically a coprimary endpoint in clinical trials evaluating treatments for chronic rhinosinusitis with nasal polyps (CRSwNP). However, a consensus on the most effective way to grade nasal polyps has not been reached. Different scales have been used, hampering the interpretation of data across trials. This review compares the characteristics of NP grading systems used in registration trials for approved NP treatments. These fundamental differences in grading systems make quantitative comparison of outcomes between trials inaccurate and potentially misleading. In lieu of a universal grading system, reporting the baseline distribution of polyp grades (unilateral and/or summed/total grades), as well as changes from baseline over time by baseline grade may help improve interpretability of outcomes and reduce inaccuracy when attempting cross-trial comparisons and making therapeutic decisions.