ABSTRACT
BACKGROUND: Echinacea preparations are widely used to treat the common cold. OBJECTIVE: To assess the efficacy of dried, encapsulated, whole-plant echinacea as early treatment for the common cold. DESIGN: Randomized, double-blind, placebo-controlled community-based trial. SETTING: University of Wisconsin-Madison, Madison, Wisconsin. PARTICIPANTS: 148 registered students with common colds of recent onset. INTERVENTION: An encapsulated mixture of unrefined Echinacea purpurea herb (25%) and root (25%) and E. angustifolia root (50%) taken in 1-g doses six times on the first day of illness and three times on each subsequent day of illness for a maximum of 10 days. MEASUREMENTS: Severity and duration of self-reported symptoms of upper respiratory tract infection. RESULTS: No statistically significant differences were detected between the echinacea and placebo groups for any of the measured outcomes. Trajectories of severity over time were nearly identical in the two groups. Mean cold duration was 6.01 days in both groups as a whole, 5.75 days in the placebo group, and 6.27 days in the echinacea group (between-group difference, -0.52 day [95% CI, -1.09 to 0.22 days]). After controlling for severity and duration of symptoms before study entry, sex, date of enrollment, and use of nonprotocol medications, researchers found no statistically significant treatment effect (adjusted hazard ratio, 1.24 [CI, 0.86 to 1.78]). Multivariable regression models assessing severity scores over time failed to detect statistically significant differences between the echinacea and placebo groups. CONCLUSION: Compared with placebo, unrefined echinacea provided no detectable benefit or harm in these college students who had the common cold.
Subject(s)
Common Cold/drug therapy , Echinacea , Phytotherapy , Plant Preparations/therapeutic use , Adolescent , Adult , Double-Blind Method , Drug Administration Schedule , Female , Humans , Male , Patient Compliance , Placebos , Plant Roots , Regression Analysis , Treatment OutcomeABSTRACT
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.
