Metabolic Heterogeneity of Obese Patients with Untreated Obstructive Sleep Apnea

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: SUN 780-806-Determinants of Insulin Resistance & Associated Metabolic Disturbances
Basic/Translational
Sunday, June 16, 2013: 1:45 PM-3:45 PM
Expo Halls ABC (Moscone Center)

Poster Board SUN-786
Alice Liu*1, James Cardell2, Clete Kushida2 and Gerald M Reaven3
1Stanford Univ, Stanford, CA, 2Stanford University, 3Stanford Med Ctr Falk CVRC, Stanford, CA
Although obstructive sleep apnea (OSA) is associated with increased prevalence of type 2 diabetes (T2DM) and/or cardiovascular disease (CVD), the relationship between OSA and metabolic abnormalities that might contribute to development of these syndromes has not been fully explored. To address this issue, we characterized metabolic variables that would increase risk of both syndromes in non-diabetic patients with untreated OSA.

Patients were recruited from the Stanford Sleep Medicine Center and communities in the surrounding Bay Area. All patients underwent overnight polysomnography (PSG). In addition, insulin-mediated glucose uptake was quantified by determining the steady-state plasma glucose (SSPG) concentration during the insulin suppression test (IST); the higher the SSPG, the more insulin resistant (IR) the individual. Body mass index (BMI), fasting plasma glucose, and lipid/lipoprotein concentrations were also determined.

Male (n=47) and female (n=20) participants had OSA, were non-diabetic, and had not received treatment for OSA. Patients were obese (mean BMI 30.6 kg/m2), 73% had moderate or severe OSA (apnea-hypopnea index, AHI ≥ 15 events/hr), and 54% had prediabetes. SSPG concentrations varied 6–fold (51 to 290 mg/dL) within the cohort, and were higher (185 vs.140 mg/dL, P<0.05) in those with severe (AHI ≥ 30 events/hr) as compared to moderate OSA (AHI 15-29.9 events/hr). Patients who were more hypoxic overnight (mean O2 saturation <93%) were more IR than those with O2 sat ≥ 93% (SSPG 203 vs 159 mg/dL, P<0.05). When patients were divided into IR (SSPG ≥ 180 mg/dL) and insulin sensitive (IS; SSPG ≤ 120 mg/dL) subgroups, 52% of the cohort was considered to be IR whereas 31% was considered IS. Among those with prediabetes, 61% were IR whereas 24% were IS. IR as compared with IS patients had higher triglycerides (204 vs. 115 mg/dL, P<0.05) and lower high-density lipoprotein cholesterol (42 vs. 56 mg/dL, P<0.01). However, no lipoprotein differences were observed when patients were stratified by AHI.

In conclusion, severe untreated OSA and worse overnight hypoxia was associated with higher SSPG concentrations. OSA patients with prediabetes were more likely to be IR, and dyslipidemia was more common in the IR subgroup. These findings demonstrate the metabolic heterogeneity of obese patients with untreated OSA, and highlight the importance of weighing these particulars when considering the relationship(s) among OSA, T2DM, and CVD.

Nothing to Disclose: AL, JC, CK, GMR

*Please take note of The Endocrine Society's News Embargo Policy at http://www.endo-society.org/endo2013/media.cfm

Sources of Research Support: NIH/ NIDDK grant 5K23 DK088877 awarded to AL; NIH/NHLBI 1U01 HL108647 awarded to GR