OSA is prevalent among patients with type II DM

Obstructive sleep apnea (OSA) has been reported to be common (prevalence ranged from 23-86%) in previous studies involving Caucasian diabetic patients. The investigators aim at finding out the prevalence of OSA in Chinese diabetic patients and identify the clinical predictors associated with OSA.

Recruited subjects will undergo overnight polysomnography, anthropometric measurements, blood tests including glycosylated hemoglobin, renal function, glucose level, blood pressure measurement both during the clinic visit and after admission for in-laboratory sleep study.

Inclusion Criteria:

• Patients, age 18 - 75, with type 2 diabetes mellitus, including those on diet, on oral-hypoglycaemic agents or on insulin
• Patients who are able to give written consent to undergo polysomnography

Exclusion Criteria:

• Patients who are unable or unwilling to give written consent to participate in the study
• Patients with unstable medical illness or poor functional performance
• Patients with recent myocardial infarction or hospital admission for congestive heart failure or cardiac arrhythmia in the past three months
• Patients on renal replacement therapy for diabetic nephropathy or chronic renal failure, or plan to start renal replacement therapy in the coming six months
• Patients suffered from recent stroke in the past six months or previous history of stroke with significant focal neurological deficit
• Patients with type I diabetes
• Pregnant lady or lactating women

All Chinese subjects with type 2 diabetes mellitus being followed up at the diabetic clinic of a University affiliated hospital