Abstract
BACKGROUND: In multiple sclerosis (MS), comorbidities and frailty are receiving increasing attention influencing disease course, treatment and quality of life. The objective of this literature review is to evaluate the evidence, strengths and weaknesses of assessment tools for comorbidities and frailty in people with MS (pwMS). METHODS: We conducted a comprehensive systematic literature review including studies published between 2014 and 2024 with original data or systematic reviews on measures of comorbidity or frailty in pwMS using PRISMA 2020 methodology. Measures were investigated focusing on underlying evidence, validity, clinical usefulness and applicability. The quality of evidence was assessed using the GRADE approach. RESULTS: Out of 4185 studies screened, 31 met inclusion criteria for comorbidity and 9 for frailty measures. We identified several frailty and comorbidity scores that have been investigated in the context of pwMS. For comorbidities these were the Charlson Comorbidity Index (n = 14 studies), Elixhauser Comorbidity Index (n = 6), Self-administered comorbidity questionnaire (n = 3) and an MS-adapted version (SRQ-MS, n = 8). For frailty, the Frailty Index (n = 8), Fried Frailty (n = 1) and Tilburg Frailty Indicator (n = 1) were identified. Quality of evidence for scores in the specific context of pwMS was graded as mostly very low to low. Applicability in clinical routine care and to real-world data was rated from low to moderate. CONCLUSION: Out of the comorbidity and frailty scales currently available, no single scale has displayed sufficient evidence to warrant routine use. Further validation and standardization are required to ensure their applicability in real-world use.