CPAP Therapy Does Not Appear to Improve Nonalcoholic Fatty Liver Disease in OSA

The use of continuous positive airway pressure (CPAP) alone does not appear to improve hepatic steatosis and fibrosis in patients with nonalcoholic fatty liver disease (NAFLD) and obstructive sleep apnea (OSA), according to the results of an analysis published in the American Journal of Respiratory and Critical Care Medicine.

Recognizing that OSA is associated with the development of NAFLD and that the effect of CPAP use in patients with NAFLD and concomitant OSA is unknown, investigators sought to explore the effects of autoCPAP vs subtherapeutic CPAP treatment on activities in these individuals during a 6-month period. Therefore, they conducted a randomized clinical trial (ClinicalTrials.gov Identifier: NCT02728765) in patients with NAFLD at the Hepatology Clinic in the Prince of Wales Hospital in Australia.

The primary study end point was the difference in changes in intrahepatic triglycerides (IHTG) levels, as evaluated via proton-magnetic resonance spectroscopy following 6 months of treatment. Key secondary end points included changes in Epworth Sleepiness Scale, controlled attenuation parameter, liver stiffness measurement (as measured by transient elastography and serum cytokeratin-18 fragment), and objective CPAP utilization by 6 months.

Individuals with NAFLD and OSA, defined by a respiratory event index (REI) of 5 or more events per hour, were randomly assigned into 1 of 2 treatment groups: (1) Group A: autoCPAP (ie, 4-20 cm H₂0) or (2) Group B: subtherapeutic CPAP (ie, pressure fixed at 4 cm H₂0).

A total of 120 participants were equally distributed between the 2 groups (n=60 in each group) between June 2016 and December 2018. The average patient age was 55 years in both groups. In Group A, 51.7% of the participants were men vs 61.7% of those in Group B. The average patient weight was 77.0±15.5 kg in Group A vs 78.5±14.8 kg in Group B.

Results of the study showed significant associations between controlled attenuation parameter and REI (P =.026), the percentage of total recording time with oxygen saturation (SaO₂) <90% (P =.003), and oxygen desaturation index (P =.019). After the 6-month treatment period, no significant differences were observed between the 2 groups regarding changes in the primary and/or secondary end points. However, based on regression analysis, weight change during 6 months was linked to changes in both IHTG and controlled attenuation parameter (P <.001).

The researchers concluded that based on the findings, which showed that the use of CPAP alone is unlikely to alter NAFLD activities in patients with concomitant OSA, the additional role played by weight reduction through lifestyle modification in this population warrants further exploration.

Disclosure: Several study authors declared affiliations with the pharmaceutical industry. Please see the original reference for a full list of authors’ disclosures.

Reference

Ng SSS, Wong VWS, Wong GLH, et al. CPAP did not improve nonalcoholic fatty liver disease in patients with obstructive sleep apnea: a randomized clinical trial. Am J Respir Crit Care Med. Published online September 14, 2020. doi:10.1164/rccm.202005-1868OC