CPAP therapy of obstructive sleep apnea in type 2 diabetics improves glycemic control during sleep.
BACKGROUND
Type 2 diabetes and obstructive sleep apnea (OSA) are frequently comorbid conditions. OSA is associated with increased insulin resistance, but studies of continuous positive airway pressure (CPAP) have shown inconsistent effects on glycemic control. However, endpoints such as hemoglobin A1c and insulin sensitivity might not reflect short-term changes in glycemic control during sleep.


METHODS
We used a continuous glucose-monitoring system to measure interstitial glucose every 5 minutes during polysomnography in 20 patients with type 2 diabetes and newly diagnosed OSA. The measurements were repeated after an average of 41 days of CPAP (range 26-96 days). All patients were on a stable diet and medications. Each 30-second epoch of the polysomnogram was matched with a continuous glucose-monitoring system reading, and the sleeping glucose level was calculated as the average for all epochs scored as sleeping.


RESULTS
The mean sleeping glucose decreased from untreated (122.0 +/- 61.7 mg/dL) to treated (102.9 +/- 39.4 mg/dL; p = 0.03 by Wilcoxon paired rank test). The sleeping glucose was more stable after treatment, with the median SD decreasing from 20.0 to 13.0 mg/dL (p = 0.005) and the mean difference between maximum and minimum values decreasing from 88 to 57 mg/dL (p= 0.003). The change in the mean hemoglobin A1c from 7.1% to 7.2% was not significant.


CONCLUSIONS
Our study is limited by the lack of a control group, but the results suggest that sleeping glucose levels decrease and are more stable after patients with type 2 diabetes and OSA are treated with CPAP.
Dawson
Arthur
A
Scripps Clinic Sleep Center Division of Chest and Critical Care Medicine, Scripps Clinic, La Jolla, CA 92037, USA. adawson1@san.rr.com
Abel
Susan L
SL
Loving
Richard T
RT
Dailey
George
G
Shadan
Farhad F
FF
Cronin
John W
JW
Kripke
Daniel F
DF
Kline
Lawrence E
LE
D000328:Adult; D000368:Aged; D001786:Blood Glucose / Q000032:analysis*; D015992:Body Mass Index; D045422:Continuous Positive Airway Pressure / Q000009:adverse effects / Q000379:methods*; D003924:Diabetes Mellitus, Type 2 / Q000150:complications / Q000378:metabolism*; D005260:Female; D006442:Glycated Hemoglobin / Q000378:metabolism; D038321:Glycemic Index; D006801:Humans; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000150:complications; D017286:Polysomnography; D020181:Sleep Apnea, Obstructive / Q000150:complications / Q000378:metabolism / Q000628:therapy*; D012913:Snoring / Q000150:complications; D018709:Statistics, Nonparametric; D016896:Treatment Outcome
D001786:Blood Glucose; D006442:Glycated Hemoglobin