Monitoring childhood asthma: web-based diaries and the asthma control test

J Allergy Clin Immunol. 2014 Jun;133(6):1599-605.e2. doi: 10.1016/j.jaci.2013.10.005. Epub 2013 Nov 28.

Abstract

Background: Data from asthma diaries are frequently used as an end point in asthma studies; however, data on the validity of Web-based diaries are scarce.

Objectives: First, we examined the validity of a Web-based diary in assessing asthma control. Second, we determined the cutoff points for well-controlled asthma of the Childhood Asthma Control Test (C-ACT) and the Asthma Control Test (ACT), and calculated the minimal important difference for both tests.

Methods: Children with asthma, ages 4-18 years (n = 228) completed a 4-week Web-based diary, C-ACT, ACT, and an asthma-related quality-of-life questionnaire at baseline and after 1-year follow-up.

Results: The completion rate of the Web-based diaries was 89%. The diary scores correlated strongly with C-ACT and ACT scores (r = -0.73, P < .01; r = -0.64, P < .01, respectively) and the changes in diary scores correlated well with changes in C-ACT and ACT scores. The best cutoff points for well-controlled asthma were C-ACT ≥ 22 and ACT ≥ 23. The minimal important differences were 1.9 (95% CI, 1.3-2.5) for ACT and 1.6 (95% CI, 1.1-2.1) for C-ACT, and -0.7 points/d (95% CI, -1.1 to -0.4) for the Web-based diary.

Conclusions: Our Web-based diary was valid for recording asthma symptoms. Cutoff points of ≥22 (C-ACT) and ≥23 (ACT) define well-controlled asthma. We recommend a 2 C-ACT and ACT points difference as minimally important.

Keywords: Asthma; GINA; Internet diaries; asthma diaries; asthma-related quality of life; childhood asthma control test; minimal important difference; pediatrics; validity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Asthma / diagnosis*
  • Asthma / drug therapy
  • Asthma / physiopathology
  • Child
  • Child, Preschool
  • Exhalation
  • Female
  • Health Records, Personal*
  • Humans
  • Internet*
  • Male
  • Nitric Oxide / analysis
  • Patient Compliance
  • Quality of Life
  • Respiratory Function Tests
  • Surveys and Questionnaires
  • Treatment Outcome

Substances

  • Nitric Oxide