MS is a very varied disease. It is hard to predict who will have relapses with MS and who will not. There is growing evidence that comorbidities, or additional health issues on top of MS, might contribute to this variability. Many people with MS also suffer from other health concerns such as hypertension (high blood pressure), diabetes, depression and anxiety. These additional conditions are linked to initial diagnostic delays, decreased quality of life, increased hospitalisations, greater disability progression, and a higher risk of death.

A recent Canadian study published in Neurology has investigated the link between comorbidities and relapse rates in people with relapsing remitting MS.

The lead scientist, Dr Kowalec, and her colleagues investigated the association between certain comorbidities and the rate of relapses in over 700 people with MS over a 2-year period.

Specifically, they looked at the link between relapse rates and additional conditions, such as: chronic obstructive pulmonary disorder (COPD); hyperlipidemia (abnormally high levels of fats in the blood); hypertension (high blood pressure); migraine; fibromyalgia (pain in the muscles or bones); heart disease; diabetes; glaucoma (an eye disease); peripheral vascular disease (PVD – a blood vessel disorder); seizure disorders; anxiety; depression; and lupus (an autoimmune disease).

They studied 764 people and found that the most common additional health condition was depression and/or anxiety, which was observed in over 60 per cent of participants. Approximately a quarter of the participants did not have any additional conditions or comorbidities. From the 75 per cent of people who did have an additional health concern, one third had one additional disease, one third had two additional diseases and the remaining third had three or more conditions.

Relapse rate

The researchers looked at whether the relapse rate was higher in people who experienced each of the additional health issues. They discovered that those with migraines, or abnormally high levels of lipids or fats in the blood (hyperlipidemia), were more likely to have a relapse. The other diseases, however, did not appear to be associated with a greater relapse rate. People with 3 or more comorbidities, regardless of which ones, were also likely to have relapses. This suggests that comorbidities play an important role in the number of relapses someone is likely to experience, which indicates these conditions are important when predicting a person’s outcome.

Why hyperlipidemia and migraines are associated with an increased risk of relapsing MS is unclear, and requires further study. However, this insight may help researchers discover some of the underlying mechanisms that lead to relapses.

Some of these comorbidities are treatable, which would help improve the quality of life of people with MS. Potentially, by treating these additional conditions, the relapse rate in people with MS could be reduced, preventing the accumulation of disabilities.

With thanks to MS Research Australia – the lead provider of research summaries on our website.