Summary. According to the study, taking into account different types of stroke and cirrhosis of the liver
Cirrhosis of the liver has an established close relationship with extrahepatic hemorrhagic and platelet processes, such as gastrointestinal bleeding, venous thromboembolism, and others. While cerebrovascular complications of cirrhosis of the liver are relatively less well understood and researched. In earlier studies reported the reduced incidence of stroke in patients with cirrhosis of the liver, established according to the autopsy. In later studies also identified reduced risk of stroke, especially of ischaemic type, but these studies have used small ad hoc cohort.
As for hemorrhagic stroke, in some previous studies the connection of certain diseases of the liver with an increased risk of intracranial hemorrhage, although other studies have not confirmed this.
In connection with the continuing uncertainty of the American scientists conducted a large-scale retrospective cohort study, which attempted to assess the relationship between liver cirrhosis and different types of stroke in a large, represented at the national level the sample consists of beneficiaries of Medicare (one of the Federal health insurance programs for older adults (over 65 years) established in 1965 in the USA). The results of this work published on 5 June 2017 in “JAMA Neurology” (“Journal of neurology American medical Association”).
This study covers 1 059 618 people during the observation period from January 1, 2008 through December 31, 2014 with a term of continuous health insurance for at least 1 year. Here we consider the various options of liver cirrhosis: alcoholic, metabolic, infectious, and also separately studied in patients with decompensated type of this disease. The main primary outcome was hospitalization about any type of stroke, the secondary — mounted separately ischemic stroke, intracerebral and subarachnoid hemorrhage. It should be clarified that patients with traumatic origins of stroke were excluded from the study.
Also experts have studied these risk factors and additional covariates: demographic, comorbidities, age, gender, ethnicity, hypertension, diabetes, atrial fibrillation, ischemic heart disease, congestive heart failure, valvular pathology of the heart, peripheral vascular disease, chronic kidney disease, chronic obstructive pulmonary disease, alcohol abuse and tobacco use.
The result among 1 618 059 beneficiaries in this study identified 15 586 (1,0%) patients with cirrhosis (mean age 74.1 years, of whom 7263 (46.6 per cent) were women). According to data provided by male study cohort had a higher prevalence of liver cirrhosis and the risk of stroke. During an average observation period during 4.3 years 77 of 268 patients were hospitalized with stroke, and note its directly proportional relationship with age and higher prevalence in the female cohort.
The overall incidence of stroke was 2.17% per year among patients with cirrhosis and 1.11% per year among patients without it. The annual incidence of ischemic stroke was made up 1.80% in patients with liver cirrhosis, intracranial hemorrhage is 0.31%, subarachnoid hemorrhage — 0,13%. The indicators for the cohort of patients without established liver cirrhosis was 0.96; 0.14 and 0.04 percent, respectively.
In the primary analysis after adjustment for demographic characteristics, risk factors for stroke and related comorbidities in patients with liver cirrhosis have higher risk of developing any type of stroke on average in 1.4 times. However, the degree of Association was higher for intracerebral (1.9 times) and subarachnoid hemorrhage (2.4 times) than for ischemic stroke (1.3 times). Regarding subtypes of ischemic stroke, cirrhosis of the liver has a mild relationship with embolicescie stroke and it is not associated with embolic subtype.
In the secondary analyses, which dealt with liver cirrhosis, associated and not associated with alcohol identified 3255 patients with alcoholic and 11 of 164 patients with non-alcoholic etiology of the disease. In this analysis, the results are mostly consistent with the primary analysis except for the risk of development of subarachnoid hemorrhage in patients with alcoholassociated liver cirrhosis, for which the risk was not statistically significant.
In addition, the identified 6043 patient with decompensated cirrhosis, who have the same risk of stroke and all individual types were slightly higher. On the contrary, moderately expressed liver disease was not associated with any type or subtype of stroke.
The discovered associations between the risk of stroke in patients with cirrhosis, the authors have several possible explanations. There is increasing evidence that liver cirrhosis is accompanied by mixed coagulopathy, with potential consequences for both hemorrhagic and thrombotic processes. Increased risk of ischemic and hemorrhagic stroke observed in this study may reflect these complex aberrations of the coagulation system, particularly in patients with more pronounced decompensated liver cirrhosis, as these people were the most increased risk of all types of stroke.
The underlying causes of liver cirrhosis such as alcohol abuse, viral hepatitis C and metabolic diseases can also determine the risk of stroke, although in this study, such associations were not identified.
As a result, the authors concluded that patients with cirrhosis are at an increased risk of stroke after adjusting for demographics, traditional risk factors for stroke and related comorbidities. Cirrhosis of the liver, appears to be more associated with hemorrhagic stroke than ischemic. A similar Association was observed regardless of the type of liver cirrhosis, while decompensated variant, apparently, had the highest correlation with any type of stroke.
At the same time, scientists clarify that further in the field of epidemiology and pathophysiology given associations more research is needed, who will be able to provide more opportunities to reduce the risk of development and prevention of stroke.