SESSION TITLE: Sleep Disorders I
SESSION TYPE: Original Investigation Slide
PRESENTED ON: Tuesday, October 29, 2013 at 02:45 PM - 04:15 PM
PURPOSE: Obstructive sleep apnea (OSA) may induce metabolic abnormalities through sleep fragmentation (clinically evaluated as daytime sleepiness), sympathetic activation and nocturnal hypoxemia. The aim of this study is to asses the relation between daytime sleepiness, apnea-hypopnea index (AHI), nocturnal oxyhaemoglobin levels and insulin resistance (IR), in nondiabetic patients with OSA.
METHODS: An ambulatory cardio-respiratory polygraphy was performed in 71 consecutive, nondiabetic patients (fasting glycemia < 126mg/dL, no hypoglycemic or hypolipemiant medication) presented for OSA evaluation. Serum triglycerides (TG), high density lipoprotein-cholesterol (HDL-C), daytime sleepiness (Epworth sleepiness scale: ESS) and anthropometric mesures were also evaluated. Correlations between ESS, AHI, desaturation index (DI), average and lowest oxyhaemoglobin saturation (SaO2), body mass index (BMI) and TG/HDL-C ratio were assesed. IR was defined as a TG/HDL-C ratio > 3, and insulin sensitivity (IS) as a TG/HDL-C ratio < 2.
RESULTS: Out of the 71 patients (51men and 20 women), 43 had IR and 11 IS. The mean age was 53±9,8 years, mean BMI: 37,2±7,2 kg/m2 (range 27-60), mean ESS: 10,27±5,2 (range 1-23) and mean AHI: 51,97±26,36 (range 4-131). 66 patients (93%) had an AHI>5/hour. The mean DI was 49,74±27,96/hour, (range: 2-133), mean average SaO2: 89,08±5,14 %, (range 74-96), and mean lowest SaO2: 68,32±14,5 % (range: 32-95). Mean TG/HDL-C ratio was 4,81 ± 4,51. ESS statistically correlated with AHI (p: 0,008 and r: 0,32), DI (p: 0,001 and r: 0,55) and inversely correlated with average SaO2 (p: 0,013 and r: -0,3). TG/HDL-C ratio negatively correlated with lowest SaO2 (p: 0,03; r: -0,27). No statistically significant correlation was found between TG/HDL-C ratio and ESS (p: 0,07), BMI (p:0,32) or DI (p: 0,13).
CONCLUSIONS: Daytime sleepiness positively correlated with AHI and DI, negatively correlated with average SaO2, and did not correlate with TG/HDL-C ratio. TG/HDL-C ratio negatively correlated with nocturnal lowest SaO2. Thus, nocturnal lowest oxyhaemoglobin level, rather than sleep fragmentation, may induce insulin resistance in nondiabetic patients.
CLINICAL IMPLICATIONS: Maintaining an adequate nocturnal oxyhaemoglobin level is important to prevent insulin resistance in nondiabetic patients with OSA.
DISCLOSURE: The following authors have nothing to disclose: Stefan Dumitrache-Rujinski, George Calcaianu, Ioana Dinu, Miron Bogdan
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