Development of the Web-Based Spanish Version of the Barthel Index in Patients with Multiple Sclerosis

The aims of this study were to develop a web-based Spanish form of the Barthel index (BI), to evaluate its psychometric properties and stability over time (test-retest), and to determine minimal detectable change (MDC) in patients with multiple sclerosis (MS).

Participants answered the BI on two forms (web-based and face-to-face interview), 7-10 days apart. The internal consistency was evaluated using Cronbach's alpha, and intraclass correlation (ICC) and kappa (κ) coefficients were used to investigate the agreement between both forms.

143 participants were included. The Spanish web-based form of the BI showed excellent agreement between both forms for each item (κ = 0.86 (0.79 to 0.92), and for total score (κ = 0.87 (0.81 to 0.93); ICC = 0.99 (0.98 to 0.99). The internal consistency was good-excellent (Cronbach's alpha = 0.89 (0.86-0.91)). The stability over time was adequate, the agreement of each item was κ = 0.63 (0.52-0.74)), and for total score (ICC = 0.97), determining a MDC₉₅ of 12.09 points.

The Spanish web-based form of the BI is a valid and reliable tool to assess functionality and can be applied in both formats in patients with MS. A total score difference of more than 12 points was found to indicate a deterioration or improvement in the patient's functionality.