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Posted by Ellen on 22:45:45 2005/06/07
In Reply to: Re: Diabetic's road tragedy raises thorny questions posted by Bonnie
Caffeine May Reduce Nocturnal Hypoglycemia in Type 1 Diabetes
Laurie Barclay, MD
June 2, 2005 Caffeine is associated with a reduction in nocturnal hypoglycemia in type 1 diabetes, according to the results of a double-blinded, randomized study published in the June issue of Diabetes Care.
"Hypoglycemia and the fear of low blood glucose levels remain rate limiting factors in achieving normoglycemia for patients with type 1 diabetes," write Tristan Richardson, MRCP, from Royal Bournemouth Hospital, U.K, and colleagues. "Previously, we have shown that ingestion of moderate amounts of caffeine also may be useful by augmenting the symptomatic and hormonal responses to mild hypoglycemia, allowing appropriate action to be taken before neuroglycopenia ensues. The benefits of regular caffeine ingestion in patients with type 1 diabetes may extend beyond its influence on hypoglycemia warning symptoms."
Using continuous glucose sensing technology and simultaneous assessment of autonomic function with Holter monitoring, the investigators studied the effect of caffeine vs placebo in 19 patients with long-standing type 1 diabetes.
Mean duration of nocturnal hypoglycemia was 49 minutes (range, 0 - 235 minutes) with caffeine and 132 minutes (range, 0 - 468 minutes) with placebo (P = .035). This reduction in duration of nighttime hypoglycemia seen with caffeine was due to a decline in the number of episodes of moderate hypoglycemia at the expense of mild hypoglycemic episodes (P = .04). Overall, there was no correlation between reduced heart rate variability (HRV), a marker of autonomic dysfunction, and hypoglycemic events (rs = 0.12; P = .62).
"Our results suggest that caffeine is associated with a significant reduction in nocturnal hypoglycemia," the authors write. "The reduction in nocturnal hypoglycemia was not linked to the concomitant rise in parasympathetic activity associated with caffeine."
Study limitations include small sample size, failure to measure the physiological and hormonal responses to hypoglycemia, and possible overestimation of nocturnal hypoglycemia.
"As impaired function of the autonomic nervous system carries a poor prognosis and our observations that short-term caffeine use improves HRV in patients with type 1 diabetes, it remains to be determined whether this translates into a reduction in risk of premature cardiac events in at-risk populations, such as individuals with type 1 diabetes," the authors conclude. "Nevertheless, the suggested beneficial effects seen here may indicate a role for caffeine in reducing nocturnal hypoglycemia."
The Institute for Scientific Information on Coffee funded this study. MiniMed Medtronic provided the glucose sensors used in this study.
Diabetes Care. 2005;28:1316-1320
Reviewed by Gary D. Vogin, MD
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