What are the causes of death in Multiple Sclerosis?
MS is generally considered to be a non-fatal disease, meaning that it isn’t the direct cause of death. However, limited mobility and other problems impose a less healthy lifestyle on people that can translate to a shorter lifespan.
Two studies have recently looked at this issue. Both were presented in October at ECTRIMS (European Committee for Treatment and Research in MS), the world’s largest medical meeting devoted to MS.
A study in British Columbia analysed the province’s database of over 6,000 people living with MS to determine the most common causes of death (Kingwell and colleagues. ECTRIMS 2012; abstract P700). Compared to the general population, people with MS had a higher risk of dying from respiratory illnesses, suicide and cardiovascular disease. The BC group previously reported that the lifespan for people with MS is about 6 years shorter than for people without MS (see How long will I live with MS?, July 4, 2012).
Another finding was that people with MS have a 14% lower risk of cancer (see Cancer risk lower in people with MS, September 13, 2012). Those results have now been published (Kingwell and colleagues. Brain2012;135(pt 10):2973-2379).
The cause of death shown on a death certificate may not be that informative because it may refer to the immediate reason rather than the underlying cause (a problem seen with people dying of Alzheimer’s disease). So a U.S. study looked at the condition leading to death rather than the cause of death in a large health plan database (Reshef and colleagues. ECTRIMS 2012; abstract P697). Information on over 31,000 people with MS was compared to data from over 92,000 people in the general population.
Overall, the death rate was twice as high among people with MS (4.9% compared to 2.4% for this sample). The most common conditions leading to death for people with MS were infections, cardiovascular disease and suicides/accidents. So these findings appear to support those from the BC study.
It may be speculated that some conditions, such as infections, respiratory illnesses and cardiovascular disease, may be due in part to lack of exercise because of mobility problems, but this needs to be studied further. The higher rate of suicide in both studies is troubling, although a recent study in the Netherlands found that the rate of suicides/accidents among people with MS wasn’t higher compared to other people (Lalmohamed and colleagues. Eur J Neurol 2012;19:1007-1014).