Comparability of the Asthma Control Test telephone interview administration format with self-administered mail-out mail-back format

摘要

Methods: This was a randomized, crossover design with subjects completing both paper and telephone interview questionnaires. Subjects were ≥18 years old, with an asthma diagnosis, and receiving treatment within the last year. Eligible subjects were randomized to one of four administration form (AF) groups – (1) Telephone–Telephone, (2) Paper–Paper, (3) Paper–Telephone, (4) Telephone–Paper. Internal consistency and test–retest reliability were compared across groups. Differential item functioning (DIF) tests were conducted at baseline to evaluate AF effects on individual ACT items. Unadjusted and adjusted mean ACT scores were compared between AFs at baseline and unadjusted and adjusted means changes in ACT scores from baseline to follow-up were compared across the four groups. Lastly, the ability of ACT scores to discriminate between self-reported asthma severity was compared between the AFs using ANOVA.