Effect of caffeine on recognition of and physiological responses to hypoglycaemia in insulin-dependent diabetes

• Published in: The Lancet (British edition) 1996-01, Vol.347 (8993), p.19-24
• Main Authors: Debrah, K, Murphy, J, Kerr, D, Sherwin, R.S
• Format: Article
• Language: English
• Subjects: Adrenal glands; Adult; Autonomic nervous system; Biological and medical sciences; Blood flow; Blood glucose; Blood Glucose - metabolism; Brain; Brain - drug effects; Brain - metabolism; Caffeine; Caffeine - pharmacology; Cerebral Arteries - drug effects; Cerebral blood flow; Cerebrovascular Circulation - drug effects; Cerebrovascular Circulation - physiology; Cognition - drug effects; Cognitive ability; Crossovers; Diabetes; Diabetes mellitus; Diabetes mellitus (insulin dependent); Diabetes Mellitus, Type 1 - blood; Diabetes Mellitus, Type 1 - physiopathology; Epinephrine; Epinephrine - blood; Event-related potentials; Factors; Female; Glucose; Glucose - metabolism; Growth Hormone - blood; Growth hormones; Hemodynamics - drug effects; Hormones. Endocrine system; Humans; Hydrocortisone - blood; Hypoglycaemia; Hypoglycemia; Hypoglycemia - physiopathology; Ingestion; Insulin; Insulin - blood; Insulin dependent diabetics; Latency; Male; Medical sciences; Middle Aged; Patients; Perception; Pharmacology. Drug treatments; Physiological effects; Physiological responses; Physiology; Recognition; Signs and symptoms; Sympathetic nervous system
• ISSN: 0140-6736; 1474-547X
• DOI: 10.1016/S0140-6736(96)91557-3

Summary Background For the patient with diabetes, hypoglycaemia unawareness—ie, the warning signs of falling blood glucose are missing—is potentially dangerous. One study has suggested that, in healthy volunteers, caffeine might be a helpful treatment. Our study looked at two effects of caffeine ingestion (250 mg) on the brain—namely, a decrease in cerebral blood flow and an increase in brain glucose use—to see if the recognition of and physiological responses to hypoglycaemia were altered in patients with insulin-dependent diabetes mellitus (IDDM). Methods 12 patients were studied twice. A hyperinsulinaemic glucose clamp was used to maintain plasma glucose at 5 mmol/L for 90 min, followed by 60 min at 3·8 mmol/L, and then 2·8 mmol/L for a further hour. After 30 min at 5 mmol/L, patients consumed, in a double-blind, crossover design, 250 mg caffeine or matched placebo. We recorded middle cerebral artery velocity (VMCA), counterregulatory hormone levels, and cognitive function, and patients recorded hypoglycaemia symptoms on a visual analogue scale. Results Caffeine caused an immediate and sustained fall in VMCA of 10 cm/s, from 60 to 50 cm/s (95% Cl -5 to -15 cm/s; p