The Wisconsin Upper Respiratory Symptom Survey (WURSS)

TABLE 2
RELIABILITY OF SYMPTOM DIMENSION MODELS

Phase 2

Between July and December 2000, 108 persons from the general population responded to advertising by calling a telephone number listed on posted flyers and in the newspaper. Of these 108 callers, 27 were eligible but declined to participate; 7 did not meet inclusion criteria (were younger than 18 years of age, had current allergy symptoms, or did not have cold symptoms); and 74 met study criteria and elected to participate (Table 3). Those declining to participate usually did so because of inconvenience in arranging an immediate interview or because compensation ($10 for interview, $15 for focus group) was insufficient. Participants were met in person for semistructured individual interviews (n = 56) or focus groups (3 groups, 20 individuals total). Two people were interviewed both individually and in focus group.

Based on the information gained during interviews, the instrument-in-development underwent 6 revisions during 2000. Each modification was tested with additional interviews. A final version was created in December 2000. A few items from the initial instrument used in the echinacea trial were modified in response to participants’ descriptions and insights. Several other items were added to reflect symptoms and functional impairments described by participants in response to our open-ended questions. All items used wording provided by participants or tested during subsequent interviews and focus groups.

All symptoms spontaneously reported by at least 3 participants in either individual interview or focus group were included in the final version (Table 4). Figure 1 provides a frequency distribution of the symptoms described during the individual interviews.

On the basis of our participants’ comments, the distribution of severity data from the echinacea trial, and recommendations from published studies, we decided to decrease the response range from a 9-point to a 7-point Likert-type severity scale. The resulting severity range was marked at 1 (very mild), 3 (mild), 5 (moderate), and 7 (severe), following the majority opinion of our respondents. Unmarked (even-numbered) options were included, as most of the respondents felt they should have “in-between” choices. The functional outcome questions adapted from the SF-36 were replaced with participant-generated items, which were then scaled in a 7-point format similar to that used for the symptoms. A final question comparing today’s global severity with yesterday’s was added to provide a comparative measure of change over time (responsiveness). Figure 2 displays the final format of WURSS items.

The qualitative data provided by our informants improved our understanding of the symptomatic and functional impact of the common cold and assisted the development of the WURSS questionnaire. Although it is clear that people experience colds in different ways, several common threads emerged. For instance, we found that our original instrument (like the Jackson criteria) had overrated individual symptoms and had underrated functional impact, interference with social relationships, and general malaise. Informants often told us that it was not necessarily the individual symptoms that bothered them, but the general feelings, described as “sick feeling,” “loss of energy,” “run down,” “tired,” “fatigue,” “malaise,” “lousy,” “lazy,” “spacey," "blah," "yucky," "foggy," "lightheaded," "fuzzy brain,” “cloudy,” “disoriented,” “uncomfortable,” “distracted,” and “miserable.” Our informants also told us that they were bothered by the way their cold interfered with day-to-day activities and relationships. Colds affected physical activities such as breathing or walking, performance at work or in the home, and interactions with friends, family, and coworkers. Terms describing the most frequent and bothersome effects were incorporated into the final WURSS instrument.

TABLE 3
INTERVIEW AND FOCUS GROUP PARTICIPANT DEMOGRAPHICS

TABLE 4
SYMPTOMS AND FUNCTIONAL IMPAIRMENTS EVALUATED BY THE WISCONSIN UPPER RESPIRATORY SYMPTOM SURVEY