HbA_1c is associated with severity of obstructive sleep apnea hypopnea syndrome in nondiabetic men

Nikolaos Papanas¹, Paschalis Steiropoulos², Evangelia Nena², Argyris Tzouvelekis², Efstratios Maltezos¹, Georgia Trakada², Demosthenes Bouros²

¹Outpatient Clinic of Obesity, Diabetes and Metabolism at the 2nd Department of Internal Medicine, ²Department of Pneumonology, Democritus University of Thrace, Alexandroupolis, Greece

Abstract: 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 (SpO₂) <90% (t < 90%) (P = 0.010). Finally, glucose and HbA_1c levels showed a significant negative correlation with average SpO₂ (P = 0.013 and P = 0.012, respectively) and, additionally, glucose levels with minimum SpO₂ (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.

Keywords: obstructive sleep apnea syndrome, glucose metabolism, glycated hemoglobin, sleep disordered breathing