Abstract
Increased serum levels of liver enzymes have been reported in patients with obstructive sleep apnea (OSA), but the prevalence of liver dysfunction in OSA is poorly defined. In 91 consecutive patients (23 females) without serological evidence of viral hepatitis or alcohol-induced liver disease who underwent nocturnal respiratory monitoring for diagnosis of OSA, we measured alanine (ALT) and aspartate (AST) aminotransferase, and gamma-glutamyltransferase (GGT) in serum, together with the HOMA Index and the lipid profile. Mean age and BMI were 55±14 (SD) yr, and 37.4±8.4 kg/m2, respectively. OSA was moderate to severe (mean AHI 49±24/h, lowest SaO2 69.3±12.8%). Increased ALT or AST (≥41 IU/L) was found in 11 and 5 patients (12% and 5.5%), respectively. Compared to patients with normal ALT levels, patients with elevated ALT were significantly younger (43.2±5.5 vs 56.4±14.3 yr, p<0.005 by unpaired t-test) and showed higher HOMA index values (8.28±5.09 vs 3.48±2.44, p<0.005) and triglyceride level (229±193 vs 132±71 mg/dL). Elevated AST levels were also significantly associated with high HOMA index. No association was found between OSA severity or the degree of obesity assessed as BMI and increased liver enzymes. Increased GGT (≥51 IU/L) occurred in 9% of the sample but showed no association with any of the variables tested. Our results suggest that increased liver enzymes are associated with more severe insulin resistance, but are not directly linked with obesity or OSA severity.
Funding by Italian Ministry of University and Research (PRIN 200895H8S9)
- © 2011 ERS