Validation of the German eHealth impact questionnaire for online health information users affected by multiple sclerosis.

Background: Persons with multiple sclerosis (MS) are confronted by an overwhelming amount of online health information, which can be valuable but also vary in quality and aim. Therefore, it is of great importance for developers and providers of eHealth information to understand its impact on the users. The eHealth Impact Questionnaire (eHIQ) has been developed in the United Kingdom to measure the potential effects of health and experimental information websites. This contains user's general attitudes towards using the internet to gain health information and attitudes towards a specific health related website. The self-complete questionnaire is divided into two independently administered and scored parts: the 11-item eHIQ part 1 and the 26-item eHIQ part 2. This study aimed to validate the psychometric properties of the German version of the eHealth Impact Questionnaire (eHIQ-G).

Methods: 162 people with multiple sclerosis browsed one of two possible websites containing information on MS and completed an online survey. Internal consistency was assessed by Cronbach's alpha and structural validity by Confirmatory Factor Analysis. Construct validity was examined by assessing correlations with the reference instruments eHealth Literacy Questionnaire and the General Self-Efficacy Scale measuring related, but dissimilar constructs. Moreover, we investigated the mean difference of the eHIQ-G score between the two websites. Data were analyzed using SPSS and AMOS software.

Results: The eHIQ-G subscales showed high internal consistency with Cronbach's alpha from 0.833 to 0.885. The 2-factor model of eHIQ part 1 achieved acceptable levels of goodness-of-fit indices, whereas the fit for the 3-factor model of eHIQ part 2 was poor and likewise for the alternative modified models. The correlations with the reference instruments were 0.08-0.62 and as expected. Older age was related with lower eHIQ part 1 score, whereas no significant effect was found for education on eHIQ part 1. Although not significant, the website 'AMSEL' reached higher mean scores on eHIQ part 2.

Conclusions: The eHIQ-G has good internal consistency, and sufficient structural and construct validity. This instrument will facilitate the measurement of the potential impact of eHealth tools.