HbA1c is associated with severity of obstructive sleep apnea hypopnea syndrome in nondiabetic men.

The aim of this study was to examine the potential correlation of sleep characteristics with glucose metabolism in nondiabetic men with obstructive sleep apnea syndrome (OSAS). Included were 31 male patients (mean age 46.7 +/- 11 years), recently diagnosed with OSAS by full polysomnography. There was a significant correlation of fasting glucose and glycosylated hemoglobin (HbA(1c)) levels with arousal index (P = 0.047 and P = 0.014, respectively). Moreover, HbA(1c) levels were correlated with apnea hypopnea index (P = 0.009), a widely accepted marker of the severity of OSAS, and with percentage of sleep time with saturation of hemoglobin with oxygen as measured by pulse oximetry (SpO(2)) < 90% (t < 90%) ( P = 0.010). Finally, glucose and HbA(1c) levels showed a significant negative correlation with average SpO(2) (P = 0.013 and P = 0.012, respectively) and, additionally, glucose levels with minimum SpO(2) (P = 0.027) during sleep. In conclusion, severity of OSAS among nondiabetic men is associated with increased HbA(1c) levels and increased fasting glucose. Thus, severity of OSAS may be an additional marker of cardiovascular risk, as well as of future diabetes, in these subjects. However, further work is needed to confirm the clinical significance of these observations.