Visual analog scale as a predictor of GINA-defined asthma control. The SACRA study in Japan

Objective. The assessment of asthma control is pivotal to treatment decisions. A questionnaire that assesses the Global Initiative for Asthma (GINA)-defined control requires four questions. A visual analog scale (VAS) to evaluate asthma control can be simply marked, but its correlation with GINA-defined control has been insufficiently evaluated. The purpose of this study is to evaluate whether VAS levels can predict GINA-defined asthma control with particular emphasis on the distinctions between "partly controlled" and "uncontrolled" and between "partly controlled" and "controlled" asthma, Methods. A cross-sectional multicenter study was carried out throughout Japan (SACRA) from March to August 2009 among patients with a diagnosis and treatment of asthma. Asthma control was studied using the GINA questionnaire and a VAS measurement of asthma severity. Pulmonary function testing was not carried out, Results. 1910 physicians enrolled 29,518 patients with asthma. 15,051 (51.0%) questionnaires were administered by physicians; patients filled out 14,076 (47.7%) questionnaires themselves. 28,225 (95.6%) of the patients were evaluable. VAS measurement of asthma symptoms was useful in predicting levels of GINA-defined control categories (the area under the receiver operating characteristic curve ranging from 0.704 to 0.837). Patients with "controlled," "partly controlled," and "uncontrolled" asthma were discriminated by VAS levels (1.50, 4.79, and 7.19). Similar results have been obtained with self- and physician-administered questionnaires showing the validity of results. Conclusion. Measurement of VAS levels is able to discriminate between patients with "controlled," "partly controlled," and "uncontrolled" asthma. The VAS score could be a simple guide in clinical situations requiring daily or regular evaluation of asthma control.