MS is a very varied disease. It is hard to predict which people with MS will have relapses and those that won’t. There is growing evidence that comorbidities, or additional health issues on top of MS might contribute to this variability. It is known that 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 diagnostic delays from symptom onset, decreased quality of life, increased hospitalisations and greater disability progression and a higher risk of death.
A recent Canadian study published in Neurology has investigated the link between co morbidities and relapse rate 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, pain in the muscles or bones (fibromyalgia), heart disease, diabetes, an eye disease (glaucoma), a blood vessel disorder (peripheral vascular disease, PVD), seizure disorders, anxiety, depression and another autoimmune disease, called Systemic lupus erythematosus.
They studied 764 people and found the most common additional health condition was depression and/or anxiety, which was observed in over 60% of participants. Approximately a quarter of the participants didn’t have any additional conditions or comorbidities. From the 75% of people that did have an additional health concern, a third had 1 additional disease, a third had 2 additional diseases and the remaining third had 3 or more conditions.
The researchers, then looked at whether the relapse rate was higher in people which suffered from each of the additional health issues. They discovered that the people which suffered migraines, or abnormally high levels of lipids or fats in the blood (hyperlipidemia) were more likely to have a relapse. The other diseases by themselves didn’t appear to be associated with a greater relapse rate. People who had 3 or more comorbidities, regardless of which ones, where also likely to suffer 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 is unclear, and requires further study however this insight may help 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 and potentially by treating these additional conditions the relapse rate in people with MS might reduce preventing the accumulation of disabilities.