Responsiveness
loss of taste or smell, post-nasal, nasal obstruction
Ability to detect change was determined by assessing change between baseline to Week 52 in individual and overall symptoms VAS and both composite VAS scores in patients believed to have experienced change (improvement or worsening) versus patients understood to be stable. Improved, stable and worsened scores, respectively, were defined as ≤ − 1, 0, ≥ 1-point changes for endoscopic NP score, ≥ 20, < − 20– < 20, ≤ − 20 L/min changes for PNIF, ≤  − 2, > − 2– < 2, ≥ 2-point changes for overall VAS symptom score, ≤ − 8.9, − 8.9– < 8.9, ≥ 8.9-point changes for SNOT-22 total score, and ≤ − 2, − 2– < 2, ≥ 2-point changes for SNOT-22 domain scores (nasal obstruction, loss of taste or smell, thick nasal discharge, facial pain/pressure, post-nasal discharge). Mean change scores were compared within and between groups and interpreted as described above for known-groups validity assessments.