OBJECTIVES: To describe the epidemiology, economic burden, and humanistic burden of MSS.

METHODS: An SLR was conducted by searching Embase, MEDLINE® and EconLit databases from inception to July 8, 2022, to identify studies assessing epidemiology and disease burden among adults with MSS.

RESULTS: Of 7,011 abstracts retrieved, 27 observational studies were included. The study sample size ranged from 22 to 20,969 (median: 345). Baseline patient characteristics varied widely across studies, where mean age ranged from 40.1 to 59.7 years; the percentage of females ranged from 40% to 85.7%. The median prevalence of spasticity among MS patients was 51.8%; spasticity was moderate/severe in 40.0% of MSS patients. Muscle spasms were the most common symptom experienced by 58% to 97% of all MSS patients, followed by urinary dysfunction and sleep disturbances. Fatigue, physical activity, heat, and stress were identified as triggers for spasticity. The mean total annual MSS treatment costs were high (e.g., EUR 114,293 in Sweden) and varied across countries. In general, the costs (total, outpatient and inpatient) and healthcare resource utilization (physiotherapy and outpatient rehabilitation) increased with increasing severity of spasticity. Around 25% higher mean indirect cost was reported among patients with severe spasticity compared to mild spasticity. Absenteeism at work due to illness was 26.5 days over 6 months, and higher for patients with moderate vs. mild spasticity. EQ-VAS, MSQoL-54 and ADL were among the commonly reported humanistic burden measures/outcomes, and their scores indicated a poorer state of health with increasing spasticity severity.

CONCLUSIONS: This SLR indicates that over half of the patients with MS, particularly those in the middle-aged group, suffer from spasticity. These patients experience high economic costs as well as poorer quality of life, both of which increase with increasing severity of spasticity. There is a lack of high-quality studies on epidemiology and economic burden in MSS, warranting further research.