Patients with liver cirrhosis have a higher risk of stroke — particularly hemorrhagic stroke — according to a new study.

Because the liver plays an integral role in the clotting process, thrombotic complications are common in patients with liver disease. Liver parenchymal cells synthesize most coagulation factors, and the liver’s reticuloendothelial system is essential in the clearance of activation products.

Previous research suggests that coagulopathy associated with cirrhosis actually helped protect against stroke, but there were no other large-scale studies to support the theory. The new study refutes this theory and offers evidence that cirrhosis-related clotting changes increase the risk of both hemorrhagic and ischemic stroke.

The newest research results, presented at the International Stroke Conference (ISC) 2017, concur with prior smaller studies. One such retrospective analysis on the medical records of 23 patients found comparatively high frequency of ischemic stroke occurring in patients with cirrhosis.

Researchers in this study performed a retrospective cohort study using a sample obtained from national Medicare data to evaluate the risk of stroke in patients with cirrhosis, and found that those patients with the liver disease had an increased risk of both ischemic and hemorrhagic stroke.

The association held up even after the scientists performed multivariate analysis that adjusted for known co-founders. The researchers also determined that the risk was greater for hemorrhagic stroke than ischemic stroke.

Using information gathered from 1,618,059 patients, the new study is one of the largest investigations into the link between cirrhosis and stroke risk to date, and the investigators found that patients with cirrhosis had a higher risk of stroke.

The researchers used data from Medicare claims filed from 2008 to 2014. The investigators evaluated a 5 percent sample, analyzing diagnostic codes for cirrhosis, stroke and known comorbidities.

The scientists included patients with at least one year of continuous Medicare coverage. They excluded patients with a history of stroke and those who presented with trauma at the time of the stroke to rule out traumatic intracerebral hemorrhage events.

Of the 1,618,059 Medicare beneficiaries reviewed, 15,586 had cirrhosis. Fifty-three percent of participants were male, and the mean age was 74.1 years.

During the nearly five years of follow-up, 77,268 of participants were hospitalized for stroke. The researchers determined the incidence of stroke was 2.17 percent annually in patients with cirrhosis of the liver and only 1.11 percent per year in those without the liver disease.

"Overall, our results challenge the notion that cirrhosis is protective against ischemic stroke and complement growing evidence of an increased risk of hemorrhagic stroke in patients with cirrhosis," says lead author of the study, Neal S. Parikh, MD, from Weill Cornell Medical College in New York City.

"Future studies should explore whether and to what extent variables such as medication use and laboratory derangements mediate the association between cirrhosis and stroke."

Limitations of the study included the exclusion of individuals under the age of 65. Furthermore, the study was based on diagnostic codes, so it may not accurately capture all the physiological variables associated with stroke into the analysis.

"The patients we studied were elderly and had a high burden of vascular risk factors, so the findings can't be generalized necessarily to all patients with liver cirrhosis," said Parikh in an interview with Medscape Medical News. "But doctors who are taking care of patients with liver cirrhosis, particularly older patients, should manage vascular risk factors appropriately."