Significant Nonalcoholic Fatty Liver Disease, Fibrosis Risk Found in Patients With Obstructive Sleep Apnea

Patients with obstructive sleep apnea (OSA) may be at an increased risk of elevated liver enzymes and incidence of nonalcoholic fatty liver disease (NAFLD), particularly those who are older and obese, according to study findings published in Cureus.

Research indicates that OSA and NAFLD are highly prevalent medical conditions, and emerging work has found that OSA may be independently related with the development and progression of NAFLD.

“The mechanisms behind this association are not well identified, but chronic intermittent hypoxia, as quantified by oxygen saturation, has been shown to be an important trigger,” explained the study authors.

Seeking to further examine this association, researchers conducted a retrospective study of adult patients with confirmed OSA evaluated at a Sleep Medicine and Research Center between January 2016 and August 2018 (N = 133; mean [SD] age, 49.8 [15.1] years; 57.1% female).

As the primary outcome, researchers evaluated the prevalence of suspected NAFLD based on steatosis, via ultrasound, and/or elevated alanine transaminase (ALT). For secondary outcomes, they performed a risk stratification of liver fibrosis using the NAFLD fibrosis score (NFS) and fibrosis-4 (FIB-4) score, which they also utilized to assess for possible predictors of liver steatosis and fibrosis.

“Liver fibrosis is an established independent predictor of disease-specific and overall mortality in patients with NAFLD,” noted researchers. “Therefore, early identification and staging of fibrosis have become increasingly important, especially in patients with risk factors for progression from simple steatosis to advanced fibrosis and cirrhosis.”

Participants presented with a mean (SD) body mass index (BMI) of 37.3 (14.5), with prevalence of OSA severity indicated as 37.9% mild, 29.6% moderate, and 32.6% severe, per apnea-hypopnea index scores.

Of the study cohort, 44.4% were found to have radiologically suspected NAFLD, with biochemically suspected NAFLD (elevated ALT liver enzymes) detected in 63.9% of participants. Moreover, features consistent with liver cirrhosis were found in 3% of those with suspected NAFLD.

High NFS and FIB-4 scores were recorded in 9% and 3.8% of all OSA patients, with low NFS and FIB-4 scores conversely recorded in 53% and 87% of participants.

In evaluating risk of high NFS scores, logistic regression analysis findings revealed that age (odds ratio [OR], 1.1; P = .018), liver cirrhosis (OR, 1326.2; P = .008), and BMI (OR, 1.2; P = .009) were significant predictors. Liver cirrhosis also served as a predictor of high FIB-4 scores (OR, 62.5; P = .047).

“Application of the NFS and FIB-4 tools to assess liver fibrosis risk would circumvent the need for liver biopsy in many patients who require careful monitoring and appropriate management, including weight loss, treating metabolic risk factors and continuous positive airway pressure treatment when indicated,” concluded the study authors.

Reference

Jawa HA, Khatib H, Alzahrani N, et al. Nonalcoholic fatty liver disease and fibrosis risk in patients with obstructive sleep apnea: a retrospective analysis. Cureus. Published online February 28, 2021. doi:10.7759/cureus.13623