Validation and psychometric properties of the Asthma Control Questionnaire among children

Abstract

Background The Asthma Control Questionnaire (ACQ) is a patient-centered tool for evaluating asthma control. It has been validated in adults but not well-validated among children. Objective We evaluated the reliability, validity, and responsiveness to change of the ACQ for assessing asthma control in children ages 6 to 17. A threshold value for poor disease control and a minimally important difference (MID) were also determined. Methods Data from 305 asthmatic children enrolled in a clinical trial were examined. The ACQ was administered at 8 visits. We analyzed results for the combined age group and for age groups 6 to 11 and 12 to 17 separately. Results Overall, the Cronbach’s alpha (internal consistency) for the ACQ was 0.74 at baseline, and the intraclass correlation coefficient (test-retest reliability) for repeated questionnaires among stable patients was 0.53. The Pearson correlations between the ACQ and other asthma questionnaires were moderate to strong (−0.64 to −0.73). Mean ACQ scores were higher (worse) in patients whose peak flow decreased, who used more rescue medications, or who sought medical care for asthma than in patients who were stable (P<0.0001 for all measures). Change in ACQ scores were significantly different among patients with deteriorating, improving, or stable asthma symptoms (P ≤0.01). The optimal threshold indicating poor asthma control was ≥1.25. The MID was established to be 0.40. Results for the separate age groups were similar. Conclusion The ACQ is a moderately reliable, valid, and responsive tool with adequate psychometric properties for assessing recent asthma control among children.

Asthma Control Assessment Tools

“…However, a trained interviewer is required to administer the questionnaire to children 6 -10 y old. 53,54 …”

“…40 The ACQ has been validated for use as a self-administered tool in-person, at home, or by telephone. 40 Moderate to strong correlations resulted from comparing the ACQ with the AQLQ (r ϭ 0.76), 54 Mini Asthma Quality of Life Questionnaire (r ϭ 0.72 and 0.74), 55 the Medical Outcomes Survey Short Form-36 (SF-36) (r ϭ 0.19 -0.55), 56 and the ACT (r ϭ Ϫ0.82 to Ϫ0.89). 13,14,19 The correlations between the ACQ and the shortened versions were high (r ϭ 0.87 with ACQ-5, 0.98 with ACQ6a, and 0.92 with ACQ-6b).…”

“…53,54,61 Also, the ACQ discriminates between groups of children with asthma based on the presence or absence of clinical events related to asthma control. 53,54 …”

“…58 The children's version of the ACQ demonstrated fair to good internal consistency (Cronbach ␣ of .42-.82) and moderate test-retest reliability (intraclass correlation coefficient ϭ 0.53). 54 …”

“…64 For the children's version of ACQ, a cutoff value of 1.25 for distinguishing between well-controlled and poorly controlled asthma was reported. 54 To assess the ability of the ACQ to predict future exacerbations, Bateman et al 64 reported a marked increase in the risk of future exacerbations in subjects with ACQ-5 scores of Ն0.75 compared with subjects with ACQ-5 scores of Ͻ0.05. In another study, Meltzer et al 65 reported that with each point increase in the ACQ score, there is a 50% higher risk of exacerbations.…”