Psychometric Validity of the Anxiety Inventory for Respiratory Disease (AIR) Scale in an Indian Sample of Chronic Obstructive Pulmonary Disease: A Cross-Sectional Study

Abstract

Introduction Researchers have found that chronic obstructive pulmonary disease (COPD) patients suffer from anxiety more than the general population. The Anxiety Inventory for Respiratory Disease (AIR) scale has been primarily used to assess non-somatic anxiety in COPD patients. The validity of AIR among COPD patients has not been evaluated in Indian settings. Therefore, this study was undertaken to determine the validity of AIR in these patients. The study aimed to evaluate concurrent criterion and discriminative validity of the AIR screening scale among patients with COPD using Mini International Neuropsychiatric Interview (MINI) 7.0.2 as the gold standard measure for diagnosing Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) anxiety disorders. Materials and methods A cross-sectional study was conducted in the Outpatients Department (OPD) of the Department of Pulmonary Medicine, All India Institute of Medical Sciences (AIIMS), New Delhi, from August 2018 to July 2019. A total of 100 patients diagnosed with COPD and aged 30 or above were recruited. All participants were further assessed in person by a psychiatry resident doctor using semi-structured proforma, MINI 7.0.2, and AIR Disease (Hindi). Mann-Whitney U and receiver operating characteristic (ROC) curves were conducted. The two-sided p-value of less than 0.05 was considered to be statistically significant. Results To assess the concurrent criterion validity of the AIR scale for screening clinical anxiety disorders, the ROC curve was constructed using MINI diagnoses of anxiety disorder as the gold standard measure. A cut-off score of 5.5 was found to maximize both the specificity and sensitivity of the AIR scale for screening anxiety disorders among COPD patients with COPD. The AIR scale showed a high sensitivity (95%) and specificity (89%) at this cut-point. Conclusion The findings of this study recommend a cut-off score of 5.5 on the AIR scale instead of 8 in previous studies, as maintaining the previously recommended cut-offs in Indian settings may lead to an increase in false negatives. This could have negative consequences for patients seeking treatment. Further studies may be planned to explore the psychometric properties of the current tool in a larger population.

Keywords: anxiety and psychosomatic symptoms in chronic diseases; concurrent criterion validity; copd: chronic obstructive pulmonary disease; dsm 5; mini-international neuropsychiatric interview (m.i.n.i.).

Figure 1. Receiver operating characteristic curves for Anxiety Inventory for Respiratory Disease (AIR) (Hindi) for correct identification of MINI diagnosis of any anxiety disorder.

The area under the receiver operating characteristic (ROC) curve for Anxiety Inventory for Respiratory Disease (AIR) (Hindi) was 0.95 (95% CI, 0.90-1.00). MINI: Mini International Neuropsychiatric Interview