Reliability
pain
Cronbach’s α coefficients indicated acceptable internal consistency and reliability. For both nasal symptoms composite VAS score, and nasal symptoms and facial pain composite VAS scores, coefficients exceeded the predefined acceptable threshold of ≥ 0.70 at Week 20 (0.910 and 0.926) and Week 52 (0.904 and 0.926). To evaluate test–retest reliability, ICC coefficients between scores at Weeks 20 and 24 were assessed in a subset of participants defined as stable (Additional file 