Estimating the rates of disability progression in people with active relapsing-remitting multiple sclerosis

SUMMARY

Estimated progression rates for people with active relapsing-remitting multiple sclerosis (RRMS) are essential for resource management but are poorly quantified according to disability severity. In this study data from the placebo arm of the AFFIRM study were used to estimate rates for a population of active RRMS patients and for a rapidly evolving severe (RES) subgroup of RRMS patients. A multistate Markov model was fitted to the data to derive a matrix of annual transition probabilities between disability states. The average progression over 2 years was estimated to be 0.27 Expanded Stability Status (EDSS) points (95% confidence interval (CI) 0.11-0.43) for active RRMS patients and 0.46 EDSS points (95% CI 0.16-0.79) for the RES subgroup. When similar baseline characteristics were used, progression in the RES subgroup was approximately 0.06-0.08 EDSS points faster per year than active RRMS patients. These results may be used for long-term forecasts of progression of these patient groups when used in conjunction with transition rates from RRMS to secondary progressive multiple sclerosis, and between secondary progressive multiple sclerosis EDSS states.

Key words: :

• relapsing-remitting multiple sclerosis
• multistate Markov model
• progression
• rapidly evolving severe
• AFFIRM
• EDSS
• pharmacoeconomic evaluations