Hypoxemia and glycemic control in type 2 diabetes mellitus with extreme obesity

Abstract

Context: Obstructive sleep apnea (OSA) has been shown to be associated with type 2 diabetes mellitus (DM). Studies on healthy individuals found that OSA is associated with lower insulin sensitivity. We hypothesized that nocturnal hypoxemia from OSA is associated with poorer glycemia in severely obese DM individuals. Copyright Design and Setting: This was a retrospective observational study of 122 non-DM, 126 non-insulintreated DM, and 35 insulin-treated DM patients. Data were collected on demographic characteristics, body mass index, and comorbidities. An overnight sleep study was performed in all patients, and OSA was defined as an apnea-hypopnea index of ≥5 events/h. Results: There were more males (P = .003) and a lower proportion of white Europeans (P = .010) among DM patients. The prevalence of OSA was 80.1% in DM and 63.1% in non-DM individuals (P = .001). DM individuals also had lower oxygen saturation (O2) (P = .0106), greater percentage of time spent under 90% oxygen saturation (%TST<90%) (P = .0067), and higher apnea-hypopnea index (P = .0085). Regression analysis showed that %TST<90% and minimum O2 saturations were associatedwithworsehemoglobinA1c resultsamongDMindividuals.Every10%reductioninminimum O2wasassociatedwitha0.3%increase inHbA1c,whereasa10%increase in%TST<90%wasassociated with a 0.2% increase in hemoglobin A1c after adjusting for a range of potential confounders. Conclusion: The high OSA prevalence in DM individuals and a positive relationship between nocturnal hypoxemia and glycemia supports the need to assess correction of hypoxemia as a management strategy for glycemic control.