[Clinical implications of serum amyloid A level in patients with obstructive sleep apnea]

To detect the levels of serum amyloid A (SAA) and explore the pathogenesis of cardiovascular diseases in patients with obstructive sleep apnea syndrome (OSAS).

Polysomnography was performed in 80 patients with OSAS and 20 control subjects matched for age and body mass index. The patients with OSAS were divided into mild OSAS group (n=22), moderate OSAS group (n=23) and severe OSAS group (n=35) according to the apnea hypopnea index (AHI). Serum amyloid A levels were measured in all the subjects by enzyme-linked immunosorbent assay for correlation analysis.

Serum amyloid A levels in mild OSAS group (1.66-/+0.73 microg/ml), moderate OSAS group (2.72-/+1.12 microg/ml) and severe OSAS group (4.08-/+1.85 microg/ml) were significantly higher than those in the control group (0.66-/+0.59 microg/ml) (P<0.05). SAA levels also differed significantly between the 3 OSAS groups (P<0.01), increasing with the severity of OSAS. Correlation analysis indicated that SAA level was positively correlated to AHI (r=0.649, P<0.01) and TSaO(2)<90% (r=0.491, P<0.01), but inversely yo miniSaO(2) (r=-0.499, P<0.01). After 3 months of nCPAP therapy, SAA levels were significantly decreased in the 20 patients with severe OSAS (4.13-/+2.27 microg/ml vs 5.14-/+2.30 microg/ml, P<0.01).

SAA levels are elevated in OSAS patients in close correlation to the severity of OSAS, which may contribute to the vulnerability of the patients to cardiovascular diseases. nCPAP therapy help reduce the risk for cardiovascular diseases in OSAS patients.