Source: Cottrell et al. The natural history of multiple sclerosis: a geographically based study. 5. The clinical features and natural history of primary progressive multiple sclerosis. Brain. 1999 Apr;122 ( Pt 4):625-39.
This study reports the natural history of 216 MS’ers with PPMS defined by at least 1 year of attack-free progression at onset. This represents 19.8% of a largely population-based patient cohort having a average follow-up of 23 years.
- The rate of deterioration from disease onset was substantially more rapid than for RRMS, with a median time to EDSS 6 (cane) and EDSS 8 (restricted mobility) of 8 and 18 years, respectively
- EDSS 6.0 = Intermittent or unilateral constant assistance (cane, crutch or brace) required to walk 100 meters with or without resting.
- EDSS 8.0 = Essentially restricted to bed, chair, or wheelchair, but may be out of bed much of day; retains self care functions, generally effective use of arms.
- A shorter time to reach EDSS 3 (moderate disability, though fully ambulatory) from onset adversely influenced time to EDSS 8.
- Involvement of three or more neurological systems at onset resulted in a median time to EDSS 10 (death) of 13.5 years in contrast to PPMS patients with one system involved at onset where median time to death from MS was 33.2 years.
- Age, gender and type of neurological system involved at onset appeared to have little influence on prognosis.
- Cause of death and familial history profile were similar in PPMS and relapse-onset MS.
- From clinical onset, rate of progression was faster in the PPMS than in the SPMS.
- However, when the rates of progression from onset of the progressive phase were compared, SPMS had a more rapid progressive phase.
- A substantial minority (28%) of the PPMS’ers had a distinct relapse even decades after onset of progressive deterioration.