CPAP therapy for patients with sleep apnea and type 2 diabetes mellitus improves control of blood pressure.
OBJECTIVE
Obstructive sleep apnea (OSA) is highly associated with type 2 diabetes mellitus (DM), and treatment of OSA may have a positive impact on cardiometabolic profile. This study investigates the effects of continuous positive airway pressure (CPAP) treatment on glycemic control and cardiometabolic parameters in patients with diabetes.


METHODS
Diabetic patients, who were newly diagnosed of OSA with an apnea hypopnea index (AHI) ≥15 and HbA1c ≥7%, were randomly assigned to either CPAP treatment or no treatment (control) for 3 months. Measurements included HbA1c, blood pressure, fasting glucose and lipids, urinary albumin, and peripheral arterial tonometry (to assess endothelial function).


RESULTS
Sixty-four patients (52 men) were randomized, with mean (±SD) age of 55.0 ± 9.6 years, body mass index of 29.9 ± 5.3 kg/m2, HbA1c of 8.1 ± 1.1%, and AHI of 45.3 ± 23.2 events/h. In the intention-to-treat analysis, no significant change in HbA1c but reduction of systolic (10 mmHg (-18 to -2), p < 0.05) and diastolic (6 mmHg (-11 to -1), p < 0.05) blood pressures were found in the CPAP group compared to the control group. Excluding those with medication changes or initiated dietary program during the study period and those who dropped out, CPAP treatment decreased HbA1c (intervention group, n = 27; control group, n = 26) by 0.4% (-0.7 to -0.1), p = 0.027.


CONCLUSIONS
In patients with type 2 DM and moderate to severe OSA, 3 months of CPAP therapy did not decrease HbA1c but lowered systolic and diastolic blood pressures. In view of a potentially limited effect size of CPAP treatment on glycemic control, sample size estimation for future randomized controlled studies must make adequate allowance for influence from external factors of medications/diet and CPAP use.
Division of Respiratory Medicine, University Department of Medicine, Queen Mary Hospital, The University of Hong Kong, 102 Pokfulam Road, Hong Kong, SAR, China.
Jamie Chung Mei
JCM
Lam
Division of Respiratory Medicine, University Department of Medicine, Queen Mary Hospital, The University of Hong Kong, 102 Pokfulam Road, Hong Kong, SAR, China.
Agnes Yuen Kwan
AYK
Lai
Division of Respiratory Medicine, University Department of Medicine, Queen Mary Hospital, The University of Hong Kong, 102 Pokfulam Road, Hong Kong, SAR, China.
Terence Chi Chun
TCC
Tam
Division of Endocrinology, University Department of Medicine, Queen Mary Hospital, The University of Hong Kong, 102 Pokfulam Road, Hong Kong, SAR, China.
Michele Mae Ann
MMA
Yuen
Division of Endocrinology, University Department of Medicine, Queen Mary Hospital, The University of Hong Kong, 102 Pokfulam Road, Hong Kong, SAR, China.|Research Centre for Heart, Brain, Hormone and Healthy Aging, The University of Hong Kong, 21 Sassoon Road, Pokfulam, Hong Kong.
Karen Siu Ling
KSL
Lam
Division of Respiratory Medicine, University Department of Medicine, Queen Mary Hospital, The University of Hong Kong, 102 Pokfulam Road, Hong Kong, SAR, China. msmip@hku.hk.|Research Centre for Heart, Brain, Hormone and Healthy Aging, The University of Hong Kong, 21 Sassoon Road, Pokfulam, Hong Kong. msmip@hku.hk.
Mary Sau Man
MSM
Ip
D000328:Adult; D000368:Aged; D000419:Albuminuria / Q000097:blood / Q000628:therapy; D001786:Blood Glucose / Q000378:metabolism; D001794:Blood Pressure / Q000502:physiology*; D015897:Comorbidity; D045422:Continuous Positive Airway Pressure; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000628:therapy*; D005260:Female; D019270:Fructosamine / Q000097:blood; D006442:Glycated Hemoglobin / Q000378:metabolism; D006801:Humans; D006973:Hypertension / Q000097:blood / Q000628:therapy*; D008055:Lipids / Q000097:blood; D008297:Male; D008875:Middle Aged; D017286:Polysomnography; D020181:Sleep Apnea, Obstructive / Q000097:blood / Q000628:therapy*
D001786:Blood Glucose; D019270:Fructosamine; D006442:Glycated Hemoglobin; D008055:Lipids; C517652:hemoglobin A1c protein, human
Blood pressure; CPAP therapy; HbA1c; Obstructive sleep apnea; Type 2 diabetes mellitus