Multiple sclerosis has changed over the years

The picture of who is affected by multiple sclerosis has changed in recent years, a phenomenon highlighted at the recent European Committee for Treatment and Research in MS (ECTRIMS), the largest annual gathering of MS specialists.

Doctors now have many tools at their disposal to detect MS, enabling them to diagnose it earlier. Despite this, several studies have now reported that the average age of people at diagnosis is older. A study in Spain found that people were typically 24 years old at diagnosis in the 1970s, but now they are about 10 years older at diagnosis (Romero-Pinel and colleagues ECTRIMS 2021; abstract P150). The reasons are unclear, but the change helps to explain why people entered into drug trials are typically in their late 30s now.

A study in Denmark found that MS has become less severe over the past 25 years (Magyari and colleagues. ECTRIMS 2021; abstract P126). People diagnosed with MS in the period 2006-2010 were 50% less likely to develop moderate or severe disability compared to those diagnosed in the late 1990s. Part of this difference may be the earlier and more widespread use of disease-modifying therapies, as some have recently argued (Tintore and colleagues. Neurology 2021; epublished September 14, 2021). Perhaps a more likely reason is the diagnostic criteria (which have changed four times in the past 20 years), which can now diagnose MS in people previously not considered to have MS and allow them to be treated.

There has been much discussion about whether MS has become more common in recent years. A new study found that the incidence of MS (i.e. the number of new cases) has not increased – at least in countries with a traditionally high incidence of MS, such as Canada, the U.S. and much of Europe (Lane and colleagues. ECTRIMS 2021; abstract P131). In contrast, countries not traditionally associated with MS have reported increases, likely due to better detection and greater public awareness of MS. For example, Iran – now a source of a great deal of MS research – has reported an increasing incidence of MS over the past three decades (Fattahi and colleagues. BMC Neurol 2021;21:400).

MS was once considered to be a rare occurrence in some groups, such as African-Americans and Hispanic Americans. The traditional view was that African-Americans generally did not get MS but it was especially severe if they did. While these impressions have changed, comparatively little data have been collected since African-Americans are often not enrolled in patient registries and are not included in clinical trials.

A group of U.S. neurologists has now set up the National African American MS Registry (, which has now enrolled just over 200 people (Williams and colleagues. ECTRIMS 2021; abstract P160). One of the goals will be to determine if African-Americans suffer worse disease and how much of an impact social factors have on outcomes. For example, in a review of the first 100 surveys, the group found that while 87% were seeing a neurologist, it typically took about four years before they were diagnosed. About 80% were taking a disease-modifying therapy.

A separate study of medical records for 200 African-Americans and Hispanic Americans found that these groups had an 8-fold higher risk of severe disability compared to White Americans (Perez and colleagues. ECTRIMS 2021; abstract P682). One reason may be that a commonly prescribed starting drug was glatiramer acetate, one of the few therapies that has not been shown to slow worsening disability. African-Americans were also less likely to respond to one of the interferons (Avonex, Rebif, Betaseron, Plegridy); they also had the highest rate of side effects with interferons – which suggests they would be better served by treatment with another disease-modifying therapy.

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