Assessment of health-related quality-of-life in patients with chronic Rhinosinusitis – Validation of the German Sino-Nasal Outcome Test-22 (German-SNOT-22)

PURPOSE: The Sino-Nasal-Outcome-Test-22 (SNOT-22) represents the reference questionnaire to assess symptoms, health-related quality-of-life (HRQOL) and treatment-response in patients with chronic rhinosinusitis (CRS). The SNOT-22 has been validated for various languages, yet no validation is available for the German version. Thus, we provide a validation of the SNOT-22 for German. METHODS: In this prospective observational study 139 CRS-patients and 36 control-participants were included. CRS-patients completed the German-SNOT-22 before treatment (T0) and four (T1), twelve (T2) and 48 weeks after inclusion (T3). At T0, Mackay-Naclerio-, Lund-Mackay- and Brief-Symptom-Inventory-18 (BSI-18) scores were collected as external reference for the German-SNOT-22 and its subscales. At T1, T2, and T3 health-transition-items (HTIs) were raised to explore responsivity. Control-participants completed the German-SNOT-22 at T0. Reliability (internal consistency, item-total correlation), validity (concurrent validity, discriminatory validity) and responsiveness (distribution- and anchor-based) were explored for the German-SNOT-22. RESULTS: At T0, the mean German-SNOT-22 total-score for CRS patients was 38.0 (± 20.9) and responded to treatment (T1 = 26.3 ± 19.1; T2 = 25.8 ± 20.6; T3 = 20.5 ± 16.3). For control-participants, the mean total-score at T0 was 15.1 (±10.9). The German-SNOT-22 was reliable (excellent internal consistency α = 0.93; good overall item-total correlations r = 0.39-0.85), valid (significant correlations between Mackay-Naclerio-, Lund-Mackay- and BSI-18 scores, all r > 0.39, p < 0.01) and responsive (significant correlations between HTIs and mean change in German-SNOT-22 total-score F = 9.57, p < 0.001). CONCLUSION: The German-SNOT-22 validated here matches the original SNOT-22. It is a reliable, valid and responsive questionnaire to assess symptoms, HRQOL and treatment-response in CRS-patients. Good psychometric properties were observed.