Validity and reliability of the persian version of the dyspnea-12 questionnaire in assessing dyspnea among COPD patients

The Persian version of Dyspnea-12 demonstrated excellent reliability (Cronbach's alpha = 0.982, Composite Reliability = 0.985). Criterion validity analysis strongly correlated with Dyspnea-12 and CAT scores (ρ = 0.698, p < 0.001). Factor analysis confirmed a single-factor structure consistent with the original version. Inter-item correlations ranged from 0.3 to 0.9. Construct validity indices indicated a satisfactory model fit (CFI = 0.904, SRMR = 0.044), though RMSEA (0.188) suggested areas for improvement. Pulmonary function analysis revealed significant associations between FEV₁ and Dyspnea-12 scores (p = 0.042) and FVC (p = 0.017), linking dyspnea severity with lung function decline.