Reliability, validity and responsiveness of a Norwegian version of the Chronic Sinusitis Survey

BACKGROUND The Chronic Sinusitis Survey (CSS) is a valid, disease-specific questionnaire for assessing health status and treatment effectiveness in chronic rhinosinusitis. In the present study, we developed a Norwegian version of the CSS and assessed its psychometric properties. METHODS In the pooled data set of 65 patients from a trial of treatment for chronic sinusitis with long-standing symptoms and signs of sinusitis on computed tomography (CT), we assessed the reliability, validity and responsiveness of the CSS. RESULTS Test-retest reliability of the two CSS scales and the total scale ranged 0.87-0.92, while internal consistency reliability ranged 0.31-0.55. CSS subscale scores were associated with other items on sinusitis symptoms, and with the Mental health and Bodily pain scale of the SF-36. There was little association of the CSS scale scores with sinus CT findings. The patients with chronic sinusitis had worse scores on all three CSS scales than a healthy reference population (n = 42) (p < 0.001). The CSS sinus symptoms subscale and the total scale were sensitive to improvement in global symptoms during 12 weeks. CONCLUSION The Norwegian version of the CSS had acceptable test-retest reliability, but lower internal consistency reliability than the accepted standard criteria. The results support the construct validity of the measure and the sinusitis symptoms subscale and the total scales were responsive to change. This supports the use of the questionnaire in interventions for chronic sinusitis, but points at problems with the internal consistency reliability.