AT AADE 16
SAN DIEGO (FRONTLINE MEDICAL NEWS) – A top endocrinologist cautioned diabetes educators that research is linking nighttime hypoglycemia to a variety of ills, and technology isn’t providing much hope – yet.
Patients with nocturnal low blood sugar “say this is the hardest thing they have to deal with. It upsets their whole day and they feel terrible,” said Anthony L. McCall, MD, PhD, James M. Moss Professor of Diabetes at the University of Virginia, Charlottesville, and vice president of clinical science with the Endocrine Society.
Dr. McCall told an audience at the annual meeting of the American Association of Diabetes Educators that half of hypoglycemia is nocturnal and unrecognized despite its dangers. According to him, hypoglycemia represents a blood glucose level of at or under 70 mg/dL (3.9 mmol/L). This is higher than the threshold for hypoglycemia in nondiabetics and those with well controlled diabetes.
Even as few as two values in a week in the range of the 60s (mg/dL) can go unrecognized and lead to full-blown hypoglycemia-associated autonomic failure, he said. There are other possible risks: “impaired sleep quality, daytime drowsiness, mood changes, risk for nocturnal falls,” he said.
Cognitive dysfunction is possible, especially in children, he added. “Neurological dysfunction may be temporary, but those who can answer simple questions may not be OK.”
There’s a potential for a vicious cycle here, he said, because people with diabetes can also develop impaired hypoglycemia awareness, making it less likely they’ll notice the low blood sugar levels that contribute to autonomic failure.
Dr. McCall reported that nighttime hypoglycemia may also:
• Trigger neurologic symptoms like those of strokes or temporary ischemic attacks. “Someone’s got check to their blood sugar,” he says.
• Lengthen the QT interval and boost the risk of irregular heartbeats.
• Contribute to “dead in bed” syndrome in which young people with type 1 diabetes are discovered dead despite not having any complications or showing signs of convulsion.
What can be done to help these patients? One approach is to combat impaired hypoglycemia awareness. Bedtime snacks, caffeine, and uncooked cornstarch are among the many nutrition supplements (and medications) that have shown inconsistent results at best on this front, Dr. McCall said. If they work, he said, they often lead to hyperglycemia.
Another strategy is to look for factors that raise the risk of nighttime hypoglycemia, such as basal insulin overtreatment, long periods between meals, delayed effects of exercise, and higher insulin sensitivity overnight.
Insulin pumps may be helpful, he said, and he generally favors their use. However, he cautioned that it’s hard to show that they reduce hypoglycemia, and some patients don’t use them properly.
Data have been mixed until recently regarding real-time continuous glucose monitoring, he said, and the devices must be worn 75%-85% of the time to show benefit. As for sensor-augmented insulin pumps, he said they’ve shown mixed results.
Dr. McCall said the artificial pancreas, once it makes it to market, could mark the beginning of a new era. “This was around the corner 40 years ago. But it’s closer now,” he said. “I have great hope that we’re going to do better.”
Dr. McCall reported being a consultant to Sanofi regarding new insulin studies and serving on the advisory board of DexCom/Google regarding the use of continuous glucose monitoring.