Serum aminotransferase levels are associated with markers of hypoxia in patients with obstructive sleep apnea.
OBJECTIVE
Nonalcoholic fatty liver disease (NAFLD) is a disorder that often presents with elevated serum aminotransferase levels. Although it has classically been linked with the metabolic syndrome, recent studies suggest NAFLD may also be associated with obstructive sleep apnea (OSA). This study evaluates the association between serum aminotransferase levels and factors connected with: either the metabolic syndrome (elevated body mass index [BMI], lipid profile, blood pressure, fasting glucose), or with OSA severity (apnea hypopnea index, lowest oxygen saturation level, oxygen desaturation index, percent of time below 90% saturation [%T<90]).


METHODS
Retrospective case series.


METHODS
109 adult patients with OSA at a university hospital general clinical research center.


RESULTS
Markers of hypoxia (lowest oxygen saturation level and %T<90), correlated significantly with aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels (Pearson's r = -0.31 to -0.38, P <0.003), while apnea hypopnea index, body mass index, blood pressure, fasting glucose, triglyceride, and cholesterol levels did not. Hierarchical linear regression was then done to determine the best predictors of aminotransferase levels. Markers of metabolic syndrome were entered as one block and markers of sleep apnea as another. Regression analyses explained 16.3% of the variance in AST and 18.9% of the variance in ALT, with %T<90 playing the largest role.


CONCLUSIONS
In patients with obstructive sleep apnea, serum aminotransferase levels are better predicted by markers of oxygen desaturation than by factors traditionally associated with the metabolic syndrome.
Norman
Daniel
D
Department of Pulmonary and Critical Care Medicine, University of California at San Diego, San Diego, CA 92103-8383, USA. d1norman@ucsd.edu
Bardwell
Wayne A
WA
Arosemena
Farah
F
Nelesen
Richard
R
Mills
Paul J
PJ
Loredo
Jose S
JS
Lavine
Joel E
JE
Dimsdale
Joel E
JE
D000328:Adult; D000410:Alanine Transaminase / Q000097:blood*; D001219:Aspartate Aminotransferases / Q000097:blood*; D015415:Biomarkers / Q000097:blood; D005234:Fatty Liver / Q000150:complications / Q000201:enzymology; D005260:Female; D006801:Humans; D000860:Hypoxia / Q000097:blood* / Q000201:enzymology / Q000209:etiology; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood; D017286:Polysomnography; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D020181:Sleep Apnea, Obstructive / Q000097:blood* / Q000150:complications
D015415:Biomarkers; D001219:Aspartate Aminotransferases; D000410:Alanine Transaminase; D010100:Oxygen