Continuous Positive Airway Pressure Treatment, Glycemia, and Diabetes Risk in Obstructive Sleep Apnea and Comorbid Cardiovascular Disease

Abstract

<b>Objective</b><div> <div>Despite evidence of a relationship between obstructive sleep apnea (OSA), metabolic dysregulation and diabetes mellitus (DM), it is uncertain whether OSA treatment can improve metabolic parameters. We sought to determine effects of long-term continuous positive airway pressure (CPAP) treatment on glycemic control and DM risk in patients with cardiovascular disease (CVD) and OSA.</div><div><strong>Research Design and Methods</strong></div><div>Blood, medical history, and personal data were collected in a substudy of 888 participants in the Sleep Apnea Cardiovascular Endpoints (SAVE) trial in which patients with OSA and stable CVD were randomized to receive CPAP plus Usual Care, or Usual Care alone. Serum glucose and glycated hemoglobin A<sub>1c</sub> (HbA<sub>1c</sub>) were measured at baseline, and six months, two- and four years, and incident diabetes diagnoses recorded.</div><div><b>Results</b></div><div>Median follow-up was 4.3 years. In those with pre-existing DM (n=274), there was no significant difference between CPAP and Usual Care groups in serum glucose, HbA<sub>1c</sub> or anti-diabetic medications during follow-up. There were also no significant between-group differences in participants with pre-diabetes (n=452), nor in new diagnoses of DM. Interaction testing suggested that women with diabetes did poorly in the Usual Care group while their counterparts on CPAP therapy remained stable.</div><div><strong>Conclusions</strong></div><div>Among patients with established CVD and OSA, we found no evidence that CPAP therapy over several years affected glycemic control in those with diabetes or pre-diabetes, or DM risk over standard of care treatment. The potential differential effect according to sex deserves further investigation.</div></div>