Measuring asthma control: a comparison of three classification systems

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 (n=8,188) 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.