The Wisconsin Upper Respiratory Symptom Survey (WURSS): a new research instrument for assessing the common cold

Abstract

Objective: To develop a sensitive, reliable, responsive, easy-to-use instrument for assessing the severity and functional impact of the common cold.

Study design: We created an illness-specific health-related quality-of-life outcomes instrument. This original questionnaire was used in a 1999 randomized trial of echinacea for the common cold. In 2000 we used cognitive interview and focus group qualitative methods to further develop the instrument. Semistructured interviews used open-ended questions to elicit symptoms, terminology, and perceived functional impact. Responses were used to improve the instrument.

Population: The randomized trial watched 142 University of Wisconsin students for a total of 953 days of illness. The subsequent qualitative instrument development project recruited 74 adults with self-diagnosed colds for 56 in-person interviews and 3 focus groups.

Outcomes measured: We measured specific symptoms, symptom clusters (dimensions), functional impact, and global severity.

Results: The original questionnaire included 20 questions: a global severity indicator, 15 symptom-severity items using 9-point severity scales, and 4 yes/no functional assessments. Data from the trial provided evidence of 4 underlying dimensions: nasal, throat, cough, and fever and aches, with reliability coefficients of 0.663, 0.668, 0.794, and 0.753, respectively. Qualitative assessments from the interviews and focus groups led us to expand from 15 to 32 symptom-specific items and from 4 to 10 functional impairment items. The original 9-point severity scale was revised to 7 points. Two global severity questions bring the item count to 44. The instrument fits comfortably on the front and back of a single sheet of paper.

Conclusions: The Wisconsin Upper Respiratory Symptom Survey (WURSS) is ready for formal validity testing or practical use in common cold research.