Obstructive sleep apnea linked to liver fibrosis regardless of obesity

Recent research has found that moderate to severe obstructive sleep apnea (OSA) is associated with Fatty liver disease fibrosis. The study was published in the journal, "European Journal of Gastroenterology & Hepatology" 2020.

Obstructive sleep apnea is one of the established factors for the pathogenesis and exacerbation of non-alcoholic fatty liver disease (NAFLD). Insulin resistance and dyslipidemia are involved in non-alcoholic fatty liver disease. Obstructive sleep apnea may also disrupt the gut liver axis, increasing intestinal permeability and with a possible role of gut microbiota in the pathogenesis of the non-alcoholic fatty liver disease. But the association between obstructive sleep apnea and the severity of the non-alcoholic fatty liver disease is not established.

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Researchers from Brazil conducted a prospective study to examine the association between obstructive sleep apnea and the severity of the non-alcoholic fatty liver disease. They included patients with at least one of metabolic syndrome (MS) criteria by assessing the NAFLD fibrosis score initially. Based on the outcome if it is an intermediate or high risk of advanced fibrosis, patients underwent liver biopsy. Patients with clinical, ultrasound or endoscopic diagnosis of cirrhosis did not undergo liver biopsy. Polysomnography was done for all the patients. Patients were divided into two groups for statistical analysis. They were patients without apnea or mild apnea and patients with moderate or severe apnea. For correlating OSA with the severity of NAFLD various risk factors like the degree of steatosis, presence, and severity of non-alcoholic steatohepatitis (NASH), and fibrosis were assessed.

The key findings of the study were:

• Fifty-one patients were evaluated.
• Of these, 80.4% had systemic arterial hypertension (SAH), 68.6% had type 2 diabetes mellitus, 62.7% had dyslipidemia, and 96.1% metabolic syndrome.
• Regarding the histological evaluation (n = 48), all had steatosis, 95.8% had steatohepatitis and 83.3% had fibrosis.
• In polysomnography, 80.4% were group 1 and 19.6% group 2.
• In univariate analysis, no correlation was found between steatosis severity, NASH, and presence or severity of fibrosis with OSA.
• A multivariate analysis adjusted for obesity level found that patients with moderate to severe OSA had an increased risk of hepatic fibrosis.

Thus, the researchers concluded that there was an association between liver fibrosis and moderate to severe obstructive sleep apnea, regardless of obesity. 

For further reading, click the following link: 10.1097/MEG.0000000000001920