Epistaxis burden in hereditary hemorrhagic telangiectasia: Validation and refinement of the NOSE-HHT

Epistaxis is the most common and burdensome manifestation of hereditary hemorrhagic telangiectasia (HHT). Bleeding severity measures do not capture the functional and emotional impact of recurrent epistaxis, highlighting the need for symptom-specific patient-reported outcome measures. This study translated and validated the Nasal Outcome Score for Epistaxis (NOSE-HHT) for Norwegian-speaking patients and evaluated whether a shortened version could be developed.

In this cross-sectional validation study, adult patients with HHT were recruited from a national tertiary referral center between October 2024 and March 2025. Psychometric evaluation followed COSMIN guidelines and included assessment of internal consistency, test-retest reliability, structural validity, construct validity, responsiveness, and item-level performance. Participants were allocated to cohorts for cross-sectional validation and item reduction (n = 157), responsiveness (n = 31), and test-retest reliability (n = 47).

A total of 235 patients were included (mean age 58.0 ± 13.5 years; 53% men). The Norwegian NOSE-HHT demonstrated excellent internal consistency (Cronbach's α = 0.955) and good test-retest reliability (ICC = 0.77; 95% CI, 0.63-0.87). Structural validity supported a single dominant underlying construct, and construct validity was confirmed by correlations with epistaxis severity and quality-of-life measures. Short-term responsiveness was limited despite improvement in bleeding-specific anchors. Item reduction yielded a 23-item version closely matching the full instrument (r = 0.995).

The Norwegian NOSE-HHT is a valid and reliable instrument for assessing epistaxis-related symptom burden in HHT. A shortened version reduces respondent burden and may facilitate use in clinical practice and future interventional studies.