To date, there are no studies that have examined the responsiveness of the Anxiety Inventory for Respiratory disease (AIR) scale to any intervention in patients with COPD. We examined the responsiveness of the AIR scale in an 8-week pulmonary rehabilitation (PR) program.
A total of 192 patients with COPD who were clinically stable and had a percent predicted FEV1 < 70% completed 8-week outpatient multidisciplinary PR. The duration of the program was 2 h per/week (1 h exercise and 1 h education). Pre- and postrehabilitation outcome measures were evaluated: exercise capacity by the incremental shuttle walk test, quality of life by the St Georges Respiratory Questionnaire (SGRQ), and severity of dyspnea by the Medical Research Council (nMRC) scale. Anxiety was measured using the self-administered AIR scale.
The mean (SD) age was 71 (8.4) years and 51% were women. The AIR scale was responsive to PR with (AIR ≥ 8, high anxiety load) a mean change pre- vs post scores (12.25 vs 6.70, t = 7.56, P < .001), in incremental shuttle walk test (183 vs 258, t = 9.49, P < .001), in total SGRQ score (62.54 vs 55.70, t = 4.77, P < .001) and in nMRC score (3.32 vs 3.04, t = 2.57, P = .03) following PR. Change in AIR was significantly correlated with change in total SGRQ (r = 0.16, P = .02) and in nMRC (r = 0.15, P = .03). The effect size for the AIR was 1.01 and minimal clinical important difference was 5.55. Anxiety is a predictor of noncompletion of PR.
The AIR scale is sensitive to change following PR in patients with COPD and can be used in future studies evaluating interventions that reduce anxiety in this disease.