Neurological comorbidity and survival in multiple sclerosis

Objective: There is increasing interest in the survival of multiple sclerosis (MS). MS itself may decrease life expectancy; however, several other comorbid diseases may also influence survival. We aimed to evaluate frequency of other neurological conditions and survival in the population-based Finnish Northern Ostrobothnia MS cohort.

Methods: The frequencies of neurological comorbid diseases and their associations with gender, clinical course, disability level (EDSS) and duration of MS were evaluated in population based cohort of 491 patients with clinically definite MS that was diagnosed between 1990 and 2010. The survival rate of the patients was also analysed.

Results: One or more neurological comorbid disease was present in 17.1% of patients (n=84). The prevalence of epilepsy in MS patients was 4.7%, which is greater than that in the general population. Migraine was significantly more common in women with a benign MS course when compared to other types of MS (p=0.046). A significant association between peripheral nervous system disorders and primary progressive MS was found (p=0.027). The 21-year survival rate from time of diagnosis was 90.5%. Stroke decreased the 21-year survival rate of the patients (p=0.003). An association between stroke prevalence and the duration of MS disease was also detected (p=0.023).

Conclusions: This is the first report of multifaceted neurological comorbidities in MS patients. Neurological comorbidity is rather common in MS. However, only the prevalence of epilepsy was increased in MS patients compared to the general population. An association between peripheral nervous system disorders and primary progressive MS was also found. The 21-year survival rate was greater in the present population based cohort compared in other studies, but stroke seems to decrease the survival rate in MS patients.