Prevalence and epidemiology of stroke in patients with multiple sclerosis: a systematic review and meta-analysis.

Background: Epidemiological data are sparse regarding the risk of stroke in patients with multiple sclerosis (MS).

Objective: To estimate the following: (1) the pooled prevalence of all-cause stroke, acute ischaemic stroke (AIS) and intracerebral haemorrhage (ICH) in MS patients; (2) the relative risk for all-cause stroke, AIS and ICH in MS patients compared to the general population; (3) associations between patient characteristics and the risk for AIS and ICH in MS patients.

Methods: Systematic review and meta-analysis of registry-based and cohort studies.

Results: Thirteen observational studies comprising 146,381 MS patients were included. The pooled prevalence of all-cause stroke was 2.7% (95% confidence interval [CI] 1.3-4.6%), with the relative risk of all-cause stroke being higher in MS patients compared to the general population (RR: 2.55; 95% CI 1.97-3.29). Subgroup analyses per stroke subtype revealed a pooled AIS prevalence of 2.1% (95% CI 0.8-4.1%) and a pooled ICH prevalence of 0.6% (95% CI 0.2-1.2%). Compared to the general population, patients with MS were found to harbour an increased risk for AIS (RR: 2.79; 95% CI 2.27-3.41) and ICH (RR: 2.31; 95% CI 1.04-5.11), respectively. The pooled prevalence of cardiovascular risk factors in MS patients was 11.5% (95% CI 2.9-24.7%) for dyslipidaemia, 18.2% (95% CI 5.9-35.3%) for hypertension and 5.4% (95% CI 2.1-10.2%) for diabetes. In meta-regression, age was negatively associated with AIS risk (β =  - .03, p = 0.04), with a 1-year increase in age resulting in a significant 3% (95%CI 0-5) attenuation of the risk of AIS.

Conclusion: The findings of the present meta-analysis indicate that MS is associated with an increased risk for ischaemic and haemorrhagic stroke. Future well-designed epidemiological studies are warranted to corroborate the robustness of the present findings in the MS population.