Age, in particular old age (> 50 years of age), is a poor prognostic factor for MS and for most other neurological disorders. The aged brain does not deal with insults very well. Why? Age chews up brain and cognitive reserve and hence the capacity for the brain to recover from attacks is limited. I am convinced that a large part of the treatment response in DMT trials is driven by recovery of function, which may explain why in almost all studies the older you are the less effective the DMT. This is particularly evident in progressive MS trials, for example in the rituximab, ocrelizumab and siponimod trials. The implications of this is that when one these drugs get to market will NICE, and other payers, dare look at the cost-effectiveness of these treatments in older pwMS and decide that it is simply not worth paying for DMTs if you are above a certain age.
Guillemin et al. Older Age at Multiple Sclerosis Onset Is an Independent Factor of Poor Prognosis: A Population-Based Cohort Study. Neuroepidemiology. 2017 Aug 10;48(3-4):179-187.
METHODS: The association of age at disease onset (adult, <50 years [AOMS], vs. late, ≥50 years [LOMS]) and time to Expanded Disability Status Scale (EDSS) score 4 and 6 was estimated by Cox regression modelling.
RESULTS: Among 3,597 patients, 245 had LOMS. Relapsing-remitting (RR) disease was less frequent with LOMS than AOMS (51.8 vs. 90.8%, p < 0.0001). PP course, LOMS and male gender predicted short time to EDSS 4 and 6. Worse outcome with LOMS (time to EDSS 4 and 6, HR 2.0 [95% CI 1.7-2.4] and 2.3 [1.9-2.9]) was independent of PP course or male gender. LOMS had greater impact on RR than PP disease (time to EDSS 4 and 6, HR 3.1 [2.3-4.0] and 4.0 [2.9-5.6]). Only LOMS predicted time from EDSS 4 to 6 (p < 0.0001).