An Investigation of the Factor Structure of the Persian Version of the Dysphagia Handicap Index

 Oropharyngeal dysphagia harms all aspects of a person’s life, including behaviors, activities, and social situations. Quality of life is a multidimensional concept. The dysphagia handicap index (DHI) is a patient-reported outcomes tool that evaluates the different dimensions of quality of life in three physical, emotional, and functional factors in English-speaking countries. The validity of the Persian version of the dysphagia handicap index (DHI) has been evaluated in a study, but the reliability and factor analysis of the Persian version has not been investigated in any study.

 This study aimed to investigate the factor structure analysis and reliability of the Persian version of the dysphagia handicap index (P-DHI).

 In this cross-sectional study, 100 patients with oropharyngeal dysphagia (mean age 55.69 ± 15.04, 53 women) completed the dysphagia handicap index (DHI). The severity of dysphagia was defined as follows: 1 for no dysphagia (normal), 2 and 3 for mild, 4, and 5 for moderate and 6 and 7for severe. Construct validity was examined by confirmatory factor analysis (CFA). Cronbach’s alpha and intraclass correlation coefficient (ICC) were performed to evaluate the internal consistency and test-retest reliability of the P-DHI, respectively.

 The results of CFA provided support for a second-order three-factor model of P-DHI (χ2 = 484.61, df = 273, (P = 0.0001), χ2/df = 1.77; CFI = 0.901; RMSEA = 0.088 and SRMR = 0.010). The Cronbach’s alpha for physical, functional, and emotional subscales and total score were 0.751, 0.836, 0.773, and 0.900, respectively. The test-retest reliability of the P-DHI for the total score and subscales was high (ICC: 0.952 - 0.988). Furthermore, a significant relationship was found between the P-DHI total score and self-reported severity of dysphagia (P = 0.0001), while there were no relationships between P-DHI total score and age (P = 0.223), sex (P = 0.936), level of education (P = 0.113), disease duration (P = 0.126).

 The P-DHI is a reliable and valid instrument for assessing the disabling effects of swallowing disorders on the one’s Quality of Life in Iranian patients with oropharyngeal dysphagia due to a variety of diseases. Also, the CFA findings provide support for the tree-factor structure of the P-DHI and the use of the subscales as distinct variables.