Development and psychometric evaluation of the treatment management adherence scale for children with multiple sclerosis

Pediatric multiple sclerosis (pMS) is a chronic inflammatory, demyelinating, and neurodegenerative disease affecting the central nervous system in children and adolescents The aim of this correlational, comparative study was to develop an assessment scale for adherence to treatment management in pMS. Two measurement tools were used to develop a scientifically sound tool to assess adherence in pediatric patients (12–18 years) diagnosed with multiple sclerosis (MS). Cases of pMS ( n = 120) in 7 hospitals in Turkey were included between August 2021-February 2022. The tools were a "Sociodemographic and Disease-Related Information" and a newly developed "Treatment Management Adherence Scale for Children with Multiple Sclerosis”. The form and questionnaire were completed by the children through online using the Zoom platform in approximately 10 min. The questionnaire on adherence contains 16 items related to the disease and treatment, scored in a 5-point Likert type. Face validity was established by pretesting with 20 children, and construct validity was established using the statistical methods of exploratory factor analysis and confirmatory factor analysis. For the reliability of the scale, Cronbach's Alpha and omega coefficients, item test correlation values, split-half, test-retest techniques were used. There were 120 eligible patients, 71.2 % girls, with mean age (±SD) 13,6 ± 2,2 years at disease onset and 15,7 ± 1,5 at the time of the study, all under disease-modifying therapy. The sample size and items were sufficient to conduct a factor analysis. The Cronbach's Alpha and Omega value was 0.75, indicating participants’ opinions were consistent across items. The mean content validity index was 0.93, showing the scale represented the measured data, and the exploratory factor analysis showed the scale measures adherence in 55 % of patients (desired figures: >0.80 and 40–60 % respectively). The 16 items of the questionnaire were grouped into 4 dimensions. These dimensions were termed 'physiological', 'self-concept', 'role function' and 'interdependence', in line with different styles of adaptation. The total score can be between 16 and 80, with higher scores indicating strong adherence to treatment. The mean total score of 54,3 ± 9,53 (min=31, max= 75) in this study was in the “moderate adherence” range. This new scale is the first to assess adherence in pMS. The study supports its validity, reliability, and likelihood to address adjustment issues in children and adolescents with MS accurately and can be recommended for clinical use.