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Introduction: Obstructive sleep apnea (OSA) is a significant risk factor for type 2 diabetes mellitus (T2DM). CPAP treatment can potentially improve glycemic control in such subjects. However, the exact effects of CPAP treatment on diabetes are uncertain. The objective of this study is to examine the effect of CPAP treatment on HbA1c levels in subjects with moderate to severe OSA and T2DM.

Methods: This is a combined retrospective and prospective study collecting data through EPIC medical record reviews. We are collecting HbA1c levels (primary outcome variable) before and after CPAP treatment in subjects with moderate to severe OSA and T2DM. The analysis will be controlled for via CPAP compliance, which will be assessed as both a categorical (adherent/non-adherent) and continuous predictor variable (number of hours of nightly usage).

Results: Reproducibility of collected data has been verified as >95% between chart reviewers on this project. We have collected data on 10 subjects so far and analysis results are pending. We hypothesize that higher levels of CPAP compliance will correlate with significant reductions in HbA1c levels in patients with both moderate to severe OSA and T2DM.

Discussion: Some studies report a decrease in HbA1c levels after CPAP treatment, while others report no significant change. All studies report that their limiting factor was variable CPAP adherence rates and small sample size. This project will add to the existing literature with a goal sample size of n=5000 and CPAP adherence rates above 70%, much higher than the national average (30%).