Insomnia linked to GERD in nonalcoholic fatty liver disease

By Lucy Piper, Senior medwireNews Reporter

Insomnia appears to be relatively common in patients with nonalcoholic fatty liver disease (NAFLD) and may occur, at least in part, as a result of gastroesophageal reflux disease (GERD) symptoms, report researchers.

The results showed that 28% of 123 patients with NAFLD had insomnia. These individuals had higher scores on the Frequent Scale for the Symptoms of GERD (FSSG) and were significantly more likely to be diagnosed with GERD (FSSG score ≥8) than individuals without insomnia, with rates of 56% versus 13%.

Moreover, proton-pump inhibitor treatment of GERD resolved insomnia in fourof nine patients who received the treatment, report the researchers, led by Yoshio Sumida (Kyoto Prefectural University of Medicine, Japan).

The team used the Athens Insomnia Scale (AIS) to measure insomnia, with a score of 6 or above indicating 25% of 40 patients with NAFL and 29% of 83 with nonalcoholic steatohepatitis had clinical insomnia. Meanwhile, 25% of each group were diagnosed with GERD.

AIS scores and the incidence of insomnia did not differ between the two groups of patients, and neither was associated with histologic findings on liver biopsy, ruling out disease severity as an underlying factor for insomnia in these patients, say Sumida et al.

Rather, they found that FSSG scores were significantly and independently associated with AIS scores.

This finding supports previously reported results of an association between insomnia and GERD, the researchers comment in the Journal of Gastroenterology.

They give two possible mechanisms for the association, including nighttime reflux causing nighttime awakening and GERD symptoms causing short, amnestic arousal leading to sleep fragmentation.

But the team also notes that recent studies have suggested a bidirectional relationship, with sleep stage possibly influencing the esophago-upper esophageal sphincter contractile reflex.

Results showing that treatment of GERD symptoms decreased both FSSG and AIS scores “also indicate that GERD symptoms are at least partly responsible for the occurrence of insomnia in NAFLD patients,” the researchers add.

GERD was not the only factor associated with insomnia, however, with levels of γ-glutamyl transpeptidase (GGT) also significantly raised in affected patients.

This increased GGT activity can be regarded as a response to oxidative stress – a common sign of obstructive sleep apnea syndrome, rates of which are also increased in patients with NAFLD, says the team.

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