The sino-nasal outcome test (SNOT)-22: validation for Greek patients

The aim of this study was to perform translation, cross-cultural adaptation, and validation of the sinonasal outcome test 22 (SNOT-22) in the Greek language. SNOT-22 was translated into Greek. A prospective study was conducted on adult patients with chronic rhinosinusitis (CRS) according to rhinosinusitis and nasal polyps (EPOS) criteria. Test–retest evaluation of the patients was carried out. Internal consistency was assessed with Cronbach’s alpha test, and test–retest reliability with Pearson’s test (parametric correlation coefficient), kappa (reproducibility) and Bland–Altman plot (extent of agreement). Validity was assessed by comparing scores between a control group of volunteers without CRS and the CRS group using Mann–Whitney test. Responsiveness was assessed on CRS patients who underwent surgery, by comparing preoperative to 3 months postoperative scores with paired t test. Furthermore the magnitude of surgery effect was evaluated. Test–retest evaluation was accepted in 64 patients. Cronbach’s alpha was 0.84 and 0.89 at test and retest, respectively, suggesting good internal consistency. Pearson’s correlation coefficient was 0.91 (p < 0.001), revealing good correlation between initial and retest scores. Mean kappa value was 0.65, indicating a high level of reproducibility, while in Bland–Altman plot the differences were located between agreement thresholds. The control group consisted of 120 volunteers. Mann–Whitney test showed a statistically significant lower score for the control group (p < 0.0001). 32 CRS patients underwent surgical treatment. Postoperative scores were significantly lower than preoperative (p < 0.0001) while the magnitude of surgery effect was considered high. Greek SNOT-22 is a valid instrument with good internal consistency, reliability, reproducibility, validity and responsiveness.