# Impact of Continuous Positive Airway Pressure Therapy on Diabetes Control in Patients With Obstructive Sleep Apnea at a Tertiary Hospital in Saudi Arabia: A Retrospective Study

## TL;DR

This study finds that CPAP therapy improves blood sugar control in diabetic patients with sleep apnea, especially those with severe cases and good adherence.

## Contribution

The study provides real-world evidence of CPAP's metabolic benefits in diabetic patients with OSA, highlighting adherence and severity as key factors.

## Key findings

- CPAP therapy significantly reduced HbA1c levels in patients with OSA and T2DM.
- Greater HbA1c reductions were seen in patients with high CPAP adherence and severe OSA.
- Lipid profiles and blood pressure remained unchanged after CPAP therapy.

## Abstract

Background: Obstructive sleep apnea (OSA) is highly prevalent among patients with type 2 diabetes mellitus (T2DM) and is recognized as an independent contributor to insulin resistance and poor glycemic control through mechanisms such as intermittent hypoxia, sleep fragmentation, and sympathetic overactivity. Continuous positive airway pressure (CPAP) therapy is the standard treatment for OSA and has been shown to improve respiratory parameters; however, evidence regarding its metabolic benefits remains inconsistent, particularly in real-world clinical practice where adherence and disease severity vary.

Objective: To evaluate changes in glycemic and metabolic parameters following CPAP therapy in patients with coexisting OSA and T2DM and to examine the influence of CPAP adherence, OSA severity, and baseline glycemic control on treatment outcomes.

Methods: A retrospective cohort study was conducted at King Fahad Hospital of the University, including adults diagnosed with both OSA and T2DM between 2018 and 2025. Demographic data, polysomnography results, and metabolic parameters were obtained from electronic medical records. Glycemic and metabolic markers were compared before and after six months of CPAP therapy. Subgroup analyses were performed according to CPAP adherence status, apnea severity, and baseline glycated hemoglobin (HbA1c) levels. Statistical analyses were performed using SPSS version 26 (IBM Corp., Armonk, NY, USA).

Results: A total of 112 patients were included in the study with a mean age of 54.2 years, and 57.1% were male. After six months of CPAP therapy, median HbA1c levels significantly decreased from 7.15% to 6.9%. Greater reductions in HbA1c were observed among patients adherent to CPAP therapy (7.55% to 6.25%), those with severe OSA (7.1% to 6.8%), and patients with baseline HbA1c levels greater than 9% (10% to 8.6%). No statistically significant changes were observed in lipid profile parameters or blood pressure measurements.

Conclusion: CPAP therapy was associated with improved glycemic control in patients with OSA and T2DM, particularly among those with higher adherence to CPAP, severe OSA, and poor baseline glycemic control.