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Do disease modifying drugs affect life expectancy?

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  1. The study in brief
  2. The study in more detail
  3. Find out more about the disease modifying drugs
  4. Browse more from the latest research

The study in brief

This study aimed to find out whether taking one of the beta interferons (Avonex, Betaferon and Rebif) would affect life expectancy by following a large group of people with relapsing remitting MS for up to 18 years.

Researchers examined medical records for almost 6000 people registered with a Canadian or a French MS clinic.  People who had died due to any cause as well as deaths considered to have been caused by MS were identified.  The researchers matched each person who had died with people who had survived and compared beta interferon exposure for the two groups.

Those who had taken beta interferons for three years or more had a 32% lower risk of all cause deaths and a 29% lower risk of MS-related deaths than those who had not taken beta interferons.  Starting one of the beta interferons late (more than five years after onset of MS or later than 40 years old) did not reduce the benefit on life expectancy.  The same benefit was also seen for people living in either Canada or France, and for both men and women.

The results suggest that people taking a beta interferon drug for more than three years were more likely to live longer than those who took one for a shorter time or who didn't take one at all.  However, even with this large group of people and long follow-up, the researchers acknowledge it is not possible to rule out other factors, such as differences in smoking or other life style factors, which could have influenced life expectancy. 

The study in more detail

Background

The beta interferons – Avonex, Betaferon, and Rebif, were the first generation of disease modifying drugs for relapsing remitting MS, introduced in the 1990s and still widely prescribed today.  Clinical trials which ran for two years showed them to be moderately effective for relapsing remitting MS.  But these relatively short clinical trials can’t tell us what impact taking a beta interferon might have over longer time frames.  This study aimed to find out what effect taking one of the beta interferons might have on life expectancy by following a large group of people with relapsing remitting MS for a longer period of time.

How this study was carried out

Researchers looked at medical records for almost 6000 people registered with a Canadian or a French MS clinic.  Exposure to beta interferons between 1996 (the first year beta interferons were available in both Canada and France) and 2013 was recorded for each person.   Deaths due to any cause were identified.  Deaths due to MS where also determined by checking death certificates for a number of contributing causes linked to severe MS, such as pneumonia or kidney infection.  The researchers matched each person who had died with people who had survived and compared beta interferon exposure for the two groups.

What was found?

During the study period, there were 742 deaths due to any cause (average age at death 61 years), 489 of which (66%) were considered to be MS-related (average age at death 59 years).  During an average of 11, and up to 18 years of follow-up, beta interferons were taken by 32% of the participants for at least 6 months. 

Those who had taken beta interferons for three years or more had a 32% lower risk of all cause deaths and a 29% lower risk of MS-related deaths than those who had not taken beta interferons.  Starting one of the beta interferons late (more than five years after onset of MS or later than 40 years old) did not reduce the benefit on life expectancy.  The same benefit was also seen for people living in either Canada or France, and for both men and women.

What does it mean?

The results suggest that people taking a beta interferon drug for more than three years were more likely to live longer than those who took one for a shorter time or who didn't take one at all. 

Other studies have found similar results.  Almost all of the people who took part in one of the early beta interferon clinical trials have been monitored in a long term follow-up.  At 21 years after the start of the study, 81 deaths were recorded.  Those who were randomly assigned to take beta interferon were found to have a 46% lower risk of death.   This finding has been interpreted with caution because of the small numbers involved in this study (366 participants); it’s possible that improved life expectancy was due to chance alone. 

The current study has the benefit of including nearly 6000 people with relapsing remitting MS, followed for up to 18 years and from two separate geographical regions.   However, even with this large group of people and long follow-up, it is not possible to rule out other factors, such as differences in smoking or other life style factors, which could have affected survival. 

The researchers would like to use their approach to investigate whether improved life expectancy extends to other, more effective, disease modifying drugs.  As some of these drugs have only become available quite recently, it may be some years before sufficient numbers of people have been taking the newer DMDs for a longer time frames to allow us to look at this.

Kingwell E, Leray E, Zhu F, et al.
Multiple sclerosis: effect of beta interferon treatment on survival
Brain 2019; Mar 18.: awz055. [Epub ahead of print]
Summary 
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Find out more about the disease modifying drugs

In the UK, there are currently 13 disease modifying drugs approved for use in the NHS for people with relapsing remitting MS.  You can read more about the drugs in MS Decisions and our booklet Disease modifying drugs: a guide to treatments for relapsing MS.  

Your MS team will tell you if you are eligible for DMDs and if so which ones would be suitable for you and your MS. They will make recommendations based on how active your MS has been, the number of relapses you have had and how these have affected you. When prescribing a DMD, your MS team has to work within NHS eligibility criteria which define the type of MS the drug can be used for.

The decision to start treatment is very personal, but there is increasing evidence that it is important to begin treating relapsing remitting MS early. This means starting DMDs soon after diagnosis. However, later is better than never, so even if you are considering DMDs after having had MS for some time, you could still benefit as the treatments may help prevent further damage from occurring.

It is important to raise the topic of starting treatment soon after diagnosis with your MS team. If it isn’t mentioned in your appointment, it is OK for you to bring it up.

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