Reuters Health Information (2005-05-26): Severe sleep apnea may damage liver
Severe sleep apnea may damage liver
Last Updated: 2005-05-26 12:15:55 -0400 (Reuters Health)
NEW YORK (Reuters Health) - Severe obstructive sleep
apnea (OSA) appears to be a risk factor for liver damage, regardless of
whether or not a patient is obese, French investigators report in the
June issue of Hepatology.
Senior author Dr. Lawrence Serfaty and colleagues hypothesized that
"OSA-induced insulin resistance and direct liver hypoxia could possibly
be involved in the pathogenesis of liver disease associated with OSA."
To test their theory, Dr. Serfaty's group evaluated 163 patients
referred to the Sleep Unit at Hospital Saint-Antoine in Paris for
clinical suspicion of OSA. None of the subjects consumed alcohol.
Polysomnography showed that 44 had severe OSA (apnea hypopnea index
(AHI) > 50/hour), 84 had moderate OSA (AHI 10 to 50/hour) and 35 had
no evidence of OSA.
Further testing revealed that liver enzymes were elevated in 14
(32%) of those with severe OSA, 15 (18%) of those with moderate OSA and
3 (8.6%) with no OSA (p = 0.02). Multivariate analysis showed that BMI
and severe OSA were independent risk factors for elevated liver enzymes.
Liver biopsies were performed in 18 of those with elevated liver
enzymes (9 with severe OSA, 6 with moderate OSA and 3 with no OSA).
Eight of those with severe OSA had steatohepatitis versus four of
those with moderate or no OSA (P = 0.04). Severe OSA was also
associated with a higher degree of lobular necrosis and fibrosis. All
three conditions, along with insulin resistance, correlated with AHI,
independent of age and BMI
"Promotion of insulin resistance is likely to be involved in the pathogenesis of liver injury," the authors suggest.
"OSA is a risk factor for abnormal liver enzymes independent of BMI
and should be investigated in patients without other cause of liver
disease," they conclude. They recommend further studies to assess the
prevalence of OSA in patients with nonalcoholic steatohepatitis "and to
evaluate whether treatment of OSA may improve liver injury."