Dyspnoea-12 is a valid and reliable measure of breathlessness in patients with ILD

Objective: To determine the validity and reliability of the Dyspnoea-12 (D-12) for the assessment of breathlessness in patients with interstitial lung disease (ILD). Methods: 101 patients with ILD completed the D-12 (scaling range 0-36, high score indicates worse dyspnea), MRC dyspnea scale, St George’s Respiratory Questionnaire (SGRQ), and Hospital anxiety and depression scale (HADS) at baseline, and 84 patients completed the D-12 and a global health transition score at follow-up 2-weeks later. D-12 psychometric properties, including floor and ceiling effects, internal consistency, test-retest reliability and construct validity of the D-12 were examined. Results: The D-12 showed good internal consistency (Cronbach’s α =0.93) and repeatability (Intra-class correlation coefficient = 0.94). Its scores were significantly associated with MRC grade (r = 0.56, p<0.001), SGRQ (symptoms r = 0.57; activities r = 0.78; impacts r = 0.75; total r = 0.79, p