Patients with multiple sclerosis (MS) are more prone to infection than people without the disease. This increased infection risk may translate to more hospitalizations among MS patients.
Results from a recent study showed that MS patients were over four times more likely to be admitted to a hospital for infection than people without MS.
One reason for these higher hospital admission rates may be MS patients' increased risk of severe infection. But the higher rates may also be due to the fact that doctors are aware of their MS patients' increased infection risk and take special precaution by referring them to hospital care.
The aim of the study – which was conducted by Professor Scott Montgomery, Örebro University and Karolinska Institutet in Sweden, and colleagues – was to assess which factors affected infection-related hospital admissions among patients with MS.
MS is a disease in which the body's immune system eats away at the protective layer around the nerves, potentially leading to nerve damage and disability. This involvement of the immune system, which protects the body against infection, may be one reason that MS patients have a higher risk of infection.
There are various forms of MS, each one characterized by the timing of symptom flare-ups and progression of disease.
The study by Professor Montgomery and colleagues included 20,276 MS patients and 203,951 people from the general population without MS. The researchers estimated participants' risk of first hospital admission for infection and death rates over 36 years.
Results showed that MS was associated with a 4.26-fold higher risk of hospital admission for all infections, compared to not having MS.
According to the researchers, "A proportion of this raised risk was probably due to surveillance and referral bias." In other words, doctors were probably more vigilant for infection in their MS patients, and thus more likely to refer those patients to the hospital upon noticing signs of infection.
Despite this surveillance bias, MS patients still had a raised risk of hospital admission when compared to other diseases that involve the immune system.
Study results also showed that compared to people without MS, patients with MS had higher rates of death within one month of hospital admission for infection, with a relative risk of 4.69.
The authors noted that these risks were higher in men and varied depending on the type of MS that patients had.
In conclusion, the authors wrote, "Higher hospital admission rates among MS patients for infection are likely to be due to a combination of surveillance bias, cautious medical management and greater susceptibility to severe infections. MS-related functional limitations may increase infection risk and this should be considered in MS management."
The study was published March 16 in the European Journal of Neurology. Funding and disclosure information was not available.