Prevalence and impact of obstructive sleep apnea in type 2 diabetes mellitus: A descriptive cross-sectional study

Background: Obstructive sleep apnea (OSA) has been reported to have a high prevalence in patients with type 2 diabetes mellitus. There is scarcity of literature on relationship between OSA and diabetes in Indian population.

Methods: A cross-sectional observational study was conducted at a tertiary care hospital and 80 consecutive and consenting patients with diabetes were enrolled over 24 months from 01 Sep 2014 to 31 Aug 2016. After a detailed history and clinical examination, all patients were subjected to a level I polysomnography (PSG), and their blood sample was drawn for the assessment of diabetes control, insulin resistance, and microvascular complications.

Results: Out of 80 patients with diabetes, 30 (37.5%) patients had a high-risk score on Berlin questionnaire and 59 (73.8%) patients had evidence of OSA by PSG. The prevalence of OSA in diabetics with normal body mass index, waist circumference, and neck circumference was 65.5%, 64.2%, and 67.2%, respectively. Patients with OSA had a significantly higher mean glycosylated hemoglobin (correlation coefficient 0.53) and higher insulin resistance (correlation coefficient 0.78). Patients with microvascular complications had a higher prevalence of OSA than those without. This included neuropathy (100% versus 62.5%), retinopathy (100% versus 69.6%) and diabetic kidney disease (DKD) (90.9% versus 52.8%). Patients with any microvascular complication were significantly more likely to have OSA (odds ratio 13.66, 95% confidence interval 3.94-47.37, p < 0.001).

Conclusion: Indian patients with diabetes have a high prevalence of OSA, regardless of obesity. Patients with diabetes and OSA have poorer diabetes control, more insulin resistance, and higher prevalence of microvascular complications like nephropathy, neuropathy, and retinopathy.