Epub ahead of print: Lalmohamed et al. Causes of death in patients with multiple sclerosis and matched referent subjects: a population-based cohort study. Eur J Neurol. 2012 Feb 21. doi: 10.1111/j.1468-1331.2012.03668.x.
Background and purpose: MS is associated with increased mortality rates. However, influence of lifestyle parameters remains unknown, and inconsistencies exist regarding findings for causes of death.
Methods: We conducted a population-based cohort study using the General Practice Research Database, Hospital Episode Statistics, and national death certificates (January 2001 through March 2008). To each MS’er (n = 1270), up to six referent subjects without MS were matched by age, gender, and practice. Complex statistical models were used to estimate mortality or death rate ratios (HRs).
Results: MS’ers had a 3.5-fold increased mortality rate for all-cause mortality, compared with referent subjects (HR 3.51, 95% CI 2.63-4.69). The rate further increased amongst current smokers (HR 6.72, 95% CI 4.16-10.87) (but not in ex-smokers) and subjects with a body mass index of <20kg/m2 (HR 6.67, 95% CI 3.50-12.73). The HR was highest for infectious/respiratory-related deaths (HR 7.69, 95% CI 4.92-12.02) and was significantly increased for deaths related to cardiovascular diseases (2.4-fold) and cancer (1.9-fold), but not for accidents and suicide related deaths.
Conclusion: British MS’ers have a 3.5-fold increased mortality rate compared with the general population. Smoking and respiratory diseases are major (potentially preventable) factors related to increased mortality rate amongst MS’ers.
“If you have MS and you are a smoker this data is telling you to stop smoking. Don’t wait; do it as soon as possible!”
“The excess deaths due to respiratory infections is almost certainly due to swallowing difficulties that come on later in the course of MS and result in aspiration pneumonia.”
“The finding that there was not an increase in suicide risk is not what I would have expected. It is well known from other studies that the suicide risk in MS’ers is ~4x higher than the general population and is particularly high in young male MS’ers who are depressed. This is why we take depression in MS so seriously and actively treat it whenever we can.”