Multiple sclerosis: comorbidities common at diagnosis

Patients newly diagnosed with multiple sclerosis (MS) often have other chronic medical conditions, with fibromyalgia, inflammatory bowel disease, and epilepsy being common physical comorbidities, and depression and bipolar disorder the most common psychiatric comorbidities, new research suggests.

Investigators, led by Ruth Ann Marrie, MD, University of Manitoba, Winnipeg, Canada, also found some interesting sex differences. In particular, women with MS were more likely to have chronic lung disease, while men with MS had a disproportionately higher prevalence of hypertension, diabetes, and epilepsy and of all of the psychiatric comorbidities studied (depression, anxiety, bipolar disorder, and schizophrenia).

The researchers note that the burden of psychiatric comorbidity for both sexes was striking.

“Depression and anxiety adversely affect health-related quality of life, adherence to therapy, and the risk of hospitalization. Therefore, our findings suggest that these comorbidities deserve particular clinical attention from the time of diagnosis, and support the need for studies aimed at improved diagnosis and management of these conditions,” they write.

The study was published online March 9 in Neurology.

Implications for Medication Choice

The investigators stress that clinicians need to be aware of any comorbidities when prescribing MS medication because they can affect drug choice.

For example, individuals with migraine may have more difficulty tolerating β interferon because of worsening headache, and diabetes increases the risk for macular edema associated with fingolimod.

Dr Marrie further states in an American Academy of Neurology press release that the current study “raises the question of whether there are shared risk factors for both MS and these other diseases, and if so, whether we could eventually find ways to reduce the risk of both MS and the other diseases.”

“Studies have shown that MS may progress faster for people who also have other chronic conditions, so it’s important for people and their doctors to be aware of this and try to manage these conditions,” she added.

For the study, researchers examined how common several chronic conditions were in 23,382 patients with MS at the time of their diagnosis and 116,638 matched controls. The conditions included were hypertension, diabetes, hyperlipidemia, heart disease, chronic lung disease, epilepsy, fibromyalgia, inflammatory bowel disease, depression, anxiety, bipolar disorder, and schizophrenia.

Of the patients with MS, 71.9% were female. The most prevalent comorbidity was depression, which was present in 19% of patients. Compared to the matched population, all comorbidities except hyperlipidemia were more common in the MS population, and several had rate ratios of 2 or more, suggesting at least double the prevalence in the MS cohort.

Table. Rate Ratios of Various Comorbidities in Patients With MS vs Controls

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Lifestyle Changes

In an accompanying editorial, William B. Grant, PhD, Sunlight, Nutrition and Health Research Center, San Francisco, California, and Trond Riise, PhD, University of Bergen, Norway, point out that many chronic diseases have similar underlying lifestyle risk factors, including low ultraviolet exposure and vitamin D concentrations, poor diet leading to obesity, low omega-3 fatty acid intake, and smoking.

Noting that the comorbid diseases were also present 5 years before MS diagnosis, they suggest that the risk for MS and the comorbid diseases may be reduced in the general population by increasing vitamin D and omega-3 fatty acid intake, eating a healthy diet, and not smoking, preferably starting early in life.

The study was supported by the Canadian Institutes of Health Research, the Rx & D Health Research Foundation, the Multiple Sclerosis Society of Canada, and Research Manitoba.

Neurology. Published online March 9, 2016. Abstract​Editorial

Sue Hughes