Improving the quality of life of multiple sclerosis patients through coping strategies in routine medical practice.
Résumé
Multiple sclerosis (MS) has a major impact on quality of life (QoL). Coping strategies which may influence QoL have not been identified. Furthermore, there is no coping scale designed to measure coping in MS patients and concise enough for routine medical practice. We used 46 items and 7 coping dimensions; we successively reduced the minimum number of dimensions through confirmatory factor analysis (CFA) and Rasch modelling. The resulting scale was submitted to psychometric validation via an independent cross-sectional analysis. After administration to 331 MS patients, we eliminated 10 of the 46 initial items; a CFA iterative algorithm identified a positive coping (PC) group and a negative coping (NC) group; an iterative reduction algorithm led to a final 10 items questionnaire, which was tested in an independent, new cross-sectional sample of 457 patients. Psychometric tests, including the Rasch model and CFA, successfully validated the scale, confirming the two dimensions and the absence of differential item functioning. The correlation between coping and QoL increased to 0.59 and 0.62 for NC and PC, respectively, compared with 0.33 found with existing scales. Our findings justify a one-dimensional overall coping scale (PC + NC). The effect of coping on QoL can be evaluated simply by adding together a positive and a negative coping strategy, for which we developed a short 10-item scale, which can be considered as an effective means of measuring the impact of coping on QoL and is ideal in routine medical practice.