Obstructive sleep apnea (OSA) is associated with development of nonalcoholic fatty liver disease (NAFLD). The effects of continuous positive airway pressure (CPAP) on NAFLD in patients with concomitant OSA are unknown.
To investigate the effects of autoCPAP versus subtherapeutic CPAP treatment over 6 months on NAFLD activities.
Patients with NAFLD and OSA, as defined by respiratory event index (REI) ≥ 5/hr diagnosed by a validated level 3 Embletta device, were randomized into group A) autoCPAP (4-20cmH2O) or group B) subtherapeutic CPAP (pressure fixed at 4cmH2O). Primary endpoint was the difference in changes in intrahepatic triglyceride (IHTG) as measured by proton-magnetic resonance spectroscopy (MRS) after 6 months of therapy. Key secondary endpoints included changes in controlled attenuation parameter (CAP) and liver stiffness measurement measured with transient elastography, and serum cytokeratin-18 fragment.
A total of 120 patients were randomized equally into two groups. There were significant correlations between CAP and REI(r=0.203, p=0.026), percentage of total recording time with SaO2<90% (r=0.265, p=0.003), and oxygen desaturation index (r=0.214, p=0.019). Following 6 months of treatment, there were no significant differences of changes in primary and secondary endpoints between the 2 treatment groups. Regression analysis showed that weight change over 6 months correlated with both changes in IHTG and CAP (p<0.001).
Despite significant correlations between hepatic steatosis and markers of severity of OSA, CPAP alone did not improve hepatic steatosis and fibrosis. However, additional role of weight reduction through lifestyle modification deserves further investigation. Clinical trial registration available at www.clinicaltrials.gov, ID: NCT02728765.