By Will Boggs, MD

NEW YORK (Reuters Health) - Late-onset multiple sclerosis (MS) is not always associated with worse outcomes than earlier adult-onset MS, according to a report in the September issue of Neurology.

"Previously it was assumed that any patient presenting with first symptoms of MS later in life (i.e., after around 50 years) had a poorer outlook/prognosis that those presenting earlier in life (i.e., adult-onset MS)," Dr. Helen Tremlett told Reuters Health. "However, our study indicates that this is not necessarily the case."

Dr. Tremlett and Dr. Virginia Devonshire from the University of British Columbia, Vancouver, Canada used survival analysis to examine prognosis and prognostic factors among 132 patients with MS first diagnosed at age 50 or older (late onset), and 2603 patients with first symptoms between age 16 and 49 (adult onset).

Motor and cerebellar, ataxia, or brainstem symptoms were more common presenting symptoms in the late-onset group, the authors report, whereas sensory and optic neuritis symptoms were more common in the adult-onset group.

Although disease progression (median time to an Expanded Disability Status Scale of 6) was significantly faster in the late-onset group (16.9 years) than in the adult-onset group (27.7 years), the results indicate, patients in the adult-onset group were significantly younger (58.4 years) than patients in the late-onset group (71.2 years) when they reached the same level of disability.

A primary progressive course was associated with more rapid progression in patients with late-onset MS, and sensory symptoms were associated with a slower progression, the researchers note.

Among patients with adult-onset MS, motor symptoms or cerebellar, ataxia, or brainstem symptoms at onset were associated with more rapid progression. In this group, the report indicates, progression was slower among women and among those with sensory symptoms and optic neuritis at presentation.

"Once the disease course was determined (i.e., relapsing or primary progressive MS) there was little difference in prognosis between late-onset or adult-onset MS," Dr. Tremlett said.

"This has real implications for those patients presenting late in life with MS," she continued. "Contrary to what we thought before, the prognosis (as measured by the EDSS) is likely to be the same as someone with adult-onset MS (once the presence of relapsing or primary progressive MS has been determined)."

"Our data do not justify recommending a different treatment approach in late-onset MS, other than on a case by case basis," the authors conclude.

Neurology 2006;67:954-959.