Those with the sleep disorder who also had poor autonomic function had significantly more hypoglycemia than those with more normal function.…
Jennifer Cheng, MD, of Rosalind Franklin University of Medicine and Science in Chicago, and colleagues reported that, those with the sleep disorder who also had poor autonomic function had significantly more hypoglycemia than those with more normal function (P<0.05).
That means that glucoregulation may be dependent on the integrity of the autonomic nervous system, they said.
Cheng stated that, “We expected that the symptomatic obstructive sleep apnea patients would have more hyperglycemia, but they actually had more hypoglycemia.” “Clinicians should take into account autonomic function when recommending tight glucose regulation because of the adverse effects that hypoglycemia can cause.”
Obstructive sleep apnea has been associated with obesity, diabetes, and hyperglycemia — the last of which may be due to increased sympathetic activity from overnight apnea, the researchers explained.
Both diabetes and dysglycemia can lead to autonomic dysfunction. In addition, abnormal glucose regulation is associated with autonomic neuropathy — a common complication of diabetes that is also associated with abnormal pulmonary function in obstructive sleep apnea.
Researchers have hypothesized that hypoglycemia may account for the higher mortality rate seen with tight glucose control in trials such as ACCORD. Hypoglycemic events may produce further autonomic dysfunction, thus leading to further hypoglycemia, the researchers explained.
So, to evaluate whether glucose regulation is affected by autonomic function, Cheng and colleagues conducted a retrospective review of charts from 77 male patients with diabetes who had been seen at a single center from 2009 to 2011. The mean age of the patients was 63; a total of 29 had sleep apnea, while 48 did not.
All of them had continuous glucose monitoring, as well as standard monitoring, over a 72-hour period, and the QTc interval prolongation — which represents the loss of adrenergic neurons — was used as a surrogate measure of autonomic dysfunction.
Cheng and colleagues found that diabetes patients with obstructive sleep apnea who had a QTc below 440 mm had more overall hypoglycemia than those with a QTc over that threshold (P<0.05). Patients without obstructive sleep apnea had no significant differences in hypoglycemia in relation to their QTc levels, they reported.
They also found that diabetes patients with obstructive sleep apnea had a higher body mass index than those without the sleep condition (36.9 versus 31.2, P<0.01). There was also a trend for increased microalbuminuria in patients with symptomatic obstructive sleep apnea, but it wasn't significant, they added.
Cheng said the take-home message is that it’s important to evaluate autonomic function when recommending a regimen of tight glycemic control. She said the work provides one potential mechanism to explain the link between tight control and poor outcomes seen in major trials.
- Explain that diabetes patients with obstructive sleep apnea may have more autonomic dysfunction and also may be at greater risk of hypoglycemia.
- Note that patients without obstructive sleep apnea had no significant differences in hypoglycemia regardless of their autonomic function.
- Note that this study was published as an abstract and presented at a conference. These data and conclusions should be considered to be preliminary until published in a peer-reviewed journal.
Cheng J, et al “Glucoregulation in diabetic patients with obstructive sleep apnea” WCIR 2011.