Measuring asthma control: a comparison of three classification systems

Abstract

There are various ways to classify asthma control; however, no classification is universally accepted. This retrospective analysis compared asthma control as assessed by the Asthma Control Questionnaire (5-item version; ACQ-5), Global Initiative for Asthma (GINA) or Gaining Optimal Asthma Control (GOAL) study criteria.Pooled data at the final study week (n58,188) from three budesonide/formoterol maintenance and reliever therapy studies which measured ACQ-5 were stratified according to GINA or GOAL criteria and ACQ-5 score distribution. The percentages of patients with a controlled/partly controlled week (GINA), totally/well-controlled week (GOAL) and range of ACQ-5 cut-off points were compared.Patients with GINA controlled, partly controlled and uncontrolled asthma had mean ACQ-5 scores of 0.43, 0.75 and 1.62, respectively. Patients with GOAL totally controlled, well-controlled and uncontrolled asthma had ACQ-5 scores of 0.39, 0.78 and 1.63. The kappa measure of agreement was 0.80 for GINA and GOAL criteria, and 0.63 for GINA controlled/partly controlled and ACQ-5 ,1.00. ACQ-5 detected clinically important improvements in 49% of patients who, according to GINA criteria, remained uncontrolled at the end of the study.Asthma control measured by GINA or GOAL criteria provides similar results. GINA Controlled/ Partly Controlled and GOAL Totally Controlled/Well-Controlled correspond to ACQ-5 ,1.00. The ACQ-5 is more responsive to change in a clinical trial setting than a categorical scale.

Asthma Control Assessment Tools

“…28,51 Furthermore, changes in the ACQ score agreed well with the changes in AQLQ and SF-36. 14 No evidence of difference in responsiveness between the original ACQ and the 3 shortened versions was reported.…”

“…14 No evidence of difference in responsiveness between the original ACQ and the 3 shortened versions was reported. 51 The minimum clinically important difference for the ACQ was found to be 0.5 for the original ACQ and slightly variable for the other versions (0.52 for ACQ-5, 0.46 for ACQ-6a, and 0.49 for ACQ-6b). 58 For the children's version, a similar minimum clinically important difference was reported (0.52) in the initial validation study with a sample of 35 children.…”

“…Therefore, 3 shortened versions of the ACQ were developed and validated: symptoms only (ACQ-5); symptoms plus FEV 1 (ACQ-6a); and symptoms plus ␤ 2 agonist (ACQ-6b). 51 Juniper et al 52 conducted a study to determine whether the questions concerning ␤ 2 agonist use and lung function testing can be removed from the ACQ for large studies without altering the validity and the measurement properties of the tool. The authors reported no evidence of a difference in scores between the complete ACQ (which is here referred to as the ACQ) and ACQ-6a.…”

Occupational exposures and uncontrolled adult-onset asthma in the European Community Respiratory Health Survey II

“…This measure of asthma control on a categorical scale, combining diurnal and nocturnal respiratory symptoms, asthma attacks, activity limitations, lung function and exacerbations, has not been formally validated. However, the classification of asthma control evaluated through GINA expert opinions in clinical settings was similar to scores from specific control questionnaires [11,12]. Epidemiological results also support the validity of such a control scale [7].…”

“…The hypothesis for this absence of trend for asthma control is that the association observed for uncontrolled asthma was mainly due to exacerbations which are not part of the definition of partly controlled asthma. Asthma control consists of two main domains: 1) lack of impairment (absence of symptoms, minimal treatment use, normal activity level and lung function level); and 2) lack of future risk to the patient (absence of asthma exacerbations, prevention of accelerated decline in lung function over time and no side-effects from medications) [4,11]. It has been suggested that exacerbations should be considered separately from current clinical control because they may occur even if the patient has adequate current control of symptoms and few activity limitations [4].…”