SNOT-22: psychometric properties and cross-cultural adaptation into the Portuguese language spoken in Brazil

Abstract

Rhinosinusitis is a highly prevalent disease and a major cause of high medical costs. It has been proven to have an impact on the quality of life through generic health-related quality of life assessments. However, generic instruments may not be able to factor in the effects of interventions and treatments. SNOT-22 is a major disease-specific instrument to assess quality of life for patients with rhinosinusitis. Nevertheless, there is still no validated SNOT-22 version in our country.

Objective: Cross-cultural adaptation of the SNOT-22 into Brazilian Portuguese and assessment of its psychometric properties.

Method: The Brazilian version of the SNOT-22 was developed according to international guidelines and was broken down into nine stages: 1) Preparation 2) Translation 3) Reconciliation 4) Back-translation 5) Comparison 6) Evaluation by the author of the SNOT-22 7) Revision by committee of experts 8) Cognitive debriefing 9) Final version. Second phase: prospective study consisting of a verification of the psychometric properties, by analyzing internal consistency and test-retest reliability.

Results: Cultural adaptation showed adequate understanding, acceptability and psychometric properties.

Conclusion: We followed the recommended steps for the cultural adaptation of the SNOT-22 into Portuguese language, producing a tool for the assessment of patients with sinonasal disorders of clinical importance and for scientific studies.

Figure 1

Establishing the clarity of SNOT-22. This shows the clarity index from each item in the “SNOT-22”. The blue bars represent the clarity index upon the first cognitive unfolding and the red bars indicate the clarity index upon the second cognitive unfolding. The dotted line shows the cutting point of 0.80 from which each item is considered clear. We notice that items 6 and 22 are located below the clarity index upon the first stage of unfolding and that all the items in “SNOT-22” were considered clear in the second cognitive unfolding. CU: cognitive unfolding.

Figure 2

Graphical representation as proposed by Bland and Altman – reproducibility. Scores from the first and second visit. On the Y axis, the difference between the scores from the first and second administrations of the questionnaire and, on the X axis, their mean values. The central red line indicates the difference between the scores from the first and second administrations of the questionnaire and the peripheral red lines indicate the mean ± two standard deviations (1.96 × SD). SD: Standard Deviation.