Cross-cultural validity of the Pulmonary Embolism Quality of Life questionnaire in the quality of life survey after pulmonary embolism: A Persian-speaking cohort

Background: The Pulmonary Embolism Quality of Life (PEmb-QoL) questionnaire is the first disease-specific scale for assessing the quality of life in patients with a history of pulmonary embolism (PE).Objectives: To assess the cross-cultural validity and reliability of the disease-specific PEmb-QoL questionnaire.Methods: The Persian version was prepared through the forward and backward translation of the English questionnaire. Six months after the diagnosis of acute PE, consecutive Persian-speaking patients were asked to complete the PEmb-QoL, the generic 36-item Short Form (SF-36) questionnaires and undertake a 6-minute walk test (6MWT). Acceptability was assessed via item missing rate, reproducibility by the test -retest method, and internal consistency reliability by Cronbach's & alpha; and McDonald's & omega; coefficients. Convergence validity was assessed using the Spearman rank correlation between scores of PEmb-QoL, SF-36, and 6MWT. The questionnaire structure was evaluated through exploratory factor analysis.Results: Ninety-six patients with a confirmed diagnosis of PE completed the ques-tionnaires. The Persian version of PEmb-QoL had good internal consistency (& alpha; = 0.95, 3-factor & omega; = 0.96), inter-item correlation (0.3-0.62), item-total correlation (0.38-0.71), reproducibility (test-retest ICC with 25 participants = 0.92-0.99), and good discrimi-nant validity. Convergence validity was confirmed by the moderate-to-high correlations between PEmb-QoL and SF-36 scores, and a good correlation between the "limitation in daily activities" dimension of the PEmb-QoL questionnaire and 6MWT results. Exploratory factor analysis suggested a 3-component structure with functional (items 1h, 4b-5d, 6, 8, 9i, and 9j), symptoms (1b-h, 7, and 8), and emotional (5a, 6, and 9a-h) components.Conclusion: The Persian version of the PEmb-QoL questionnaire is valid and reliable for measuring the disease-specific quality of life in patients with PE.