Validation of the eHEALS-instrument in a restless legs syndrome population: A Classical Test Theory and Rasch Analysis study (Preprint)
Authors: Georgsson Mattias , Odzakovic Elzana , Björk Maria , Kaldo Viktor , Jernelöv Susanna , Blom Kerstin , Ulander Martin , Fridlund Bengt , Knutsson Susanne , Sandlund Christina , Pakpour Amir , Broström Anders 
Published: November 2024

BACKGROUND

An increased use of the Internet and digital healthcare for patients with long-term conditions implies a need for assuring digital health literacy skills. Patients with restless legs syndrome (RLS) is a group where digital sources of information are highly valued. This is due to a difficult diagnosis and complex treatment situation that contributes to patients seeking out online resources themselves to handle the perceived shortcomings in their care. To benefit from these resources, patients need to have the digital skills to explore information to optimize their understanding of the disease and its treatments. The eHealth Literacy Scale (eHEALS), which has been used in both general populations and patients with long-term conditions could, if proven valid, be used by researchers and clinicians to assess digital health literacy among patients with RLS to inform the development of patient-centered digital healthcare information and interventions.

OBJECTIVE

To investigate the psychometric properties of eHEALS in patients with RLS to determine its adequacy and potential utility.

METHODS

A cross-sectional design including patients with RLS from a national RLS patient organization was used. Data was collected via a mail-based survey comprising the following instruments: eHEALS, Restless Legs Syndrome-6 Scale (RLS symptoms), Pittsburgh Sleep Quality Inventory (sleep quality), Epworth Sleepiness Scale (daytime sleepiness), Patient Health Questionnaire-9 (depressive symptoms), and CollaboRATE (shared decision-making). Confirmatory factor analysis and Rasch models were used to assess the validity and reliability of the eHEALS. Measurement invariance, unidimensionality and differential item functioning across age, gender, medication use, sleep quality, level of depressive symptoms and participation in care decisions were assessed.

RESULTS

A total of 788 patients with a mean (SD) age of 70.8 (11.3) years participated. Among the patients, 65% were females, 75% were married/living together, and 45% had attained a university education. A median eHEALS score (q1-3) of 28 (22, 33) was reported. The unidimensionality of the eHEALS was supported by the confirmatory factor analysis and Rasch model. The reliability of the eHEALS was confirmed using composite reliability and Cronbach’s alpha. No differential item functioning was identified for age, gender, medication use, shared decision-making condition, depressive symptoms, or sleep quality meaning these have different probabilities of endorsing a given item on a multi-item scale after controlling for overall scale scores.

CONCLUSIONS

The eHEALS showed good validity and reliability and operated equivalently for male and female patients of different ages with various clinical- and treatment conditions related to RLS. Accordingly, healthcare professionals can use eHEALS as a psychometrically sound tool to explore digital health literacy level among patients with RLS.