Validation of the functional assessment of chronic illness therapy – General treatment satisfaction (FACIT-TS-G) in multiple sclerosis

Abstract

BackgroundPatient-reported treatment satisfaction is associated with medication adherence and persistence, making it increasingly important in the multiple sclerosis (MS) population, where disease modifying treatments (DMTs) can be vital in preventing accumulation of disability. Therefore, the valid assessment of treatment satisfaction is critical in MS care. The current study aimed to examine the validity of the Functional Assessment of Chronic Illness Therapy – General Treatment Satisfaction (FACIT-TS-G) in an MS population. MethodsPatient-reported outcome (PRO) data were collected from 555 MS patients (mean age 47.99±11.57; 76.4% female; 78.7% White/Caucasian) as part of routine clinical care. The FACIT-TS-G reliability, validity, and factor structure were examined. FACIT-TS-G scores were compared between DMT administration type (oral, injection, infusion) and examined as a possible predictor of switching DMT type at 1-to-2-year follow-up. ResultsThe FACIT-TS-G showed good internal consistency (Cronbach's α=0.836), convergent validity, and known-group validity. Confirmatory factor analyses supported a single factor. DMT infusion administration was associated with slightly greater FACIT-TS-G scores than injection (p = 0.013, 95% CI: 0.269, 2.273) and oral administration (p = 0.030, 95% CI: 0.087, 1.717). FACIT-TS-G scores did not predict the likelihood of switching DMT type at follow-up (p>0.05). ConclusionOur findings support the use of the FACIT-TS-G as a PRO measure of treatment satisfaction in MS. Moreover, results suggest DMT administration via infusion is associated with greater treatment satisfaction. Future research is needed to examine treatment satisfaction in the context of other outcomes.