Cross-cultural adaptation and validation of the SNOT-22 into Italian.

The aim of this study is to evaluate the reliability and validity of the Italian SNOT-22 (I-SNOT-22). The study consisted of five phases: item generation, reliability analysis, normative data generation, validity analysis and responsiveness analysis. The item generation phase followed the five-step, cross-cultural, adaptation process of translation and back-translation. A group of 222 patients with chronic rhinosinusitis (CRS) were enrolled for the internal consistency analysis. Sixty patients completed the I-SNOT-22 twice, 2 weeks apart, for test-retest reliability analysis. A group of 119 asymptomatic subjects completed the I-SNOT-22 for normative data generation. I-SNOT-22 scores obtained by CRS patients and asymptomatic subjects were compared for validity analysis. I-SNOT-22 scores were correlated with Lund-Mackay and visual analogue scale (VAS) scores in 50 CRS patients for criterion validity analysis. Finally, I-SNOT-22 scores obtained in a group of 59 CRS patients before and after surgical treatment for CRS were compared for responsiveness analysis. All the enrolled subjects managed to complete the I-SNOT-22 without needing any assistance. Internal consistency was satisfactory (α = 0.86). Test-retest reliability was also satisfactory (ICC = 0.85). A significant difference in the I-SNOT-22 scores between the CRS patients and the asymptomatic subjects was found (p < 0.008). Positive significant correlations were found between I-SNOT-22 and VAS scores, while no significant correlations were found between I-SNOT-22 scores and Lund-Mackay scores. I-SNOT-22 scores obtained in the pre-treatment condition were significantly higher than those obtained after surgery. I-SNOT-22 is reliable, valid, responsive to changes in QOL, and recommended for clinical practice and outcome research.