title: Cognitive performance, symptoms and counter-regulation during hypoglycaemia in patients with type 1 diabetes and high or low renin-angiotensin system activity.
abstract: BACKGROUND
  High basal renin-angiotensin system (RAS) activity is associated with increased risk of severe hypoglycaemia in type 1 diabetes. We tested whether this might be explained by more pronounced cognitive dysfunction during hypoglycaemia in patients with high RAS activity than in patients with low RAS activity.
  
  
  METHODS
  Nine patients with type 1 diabetes and high and nine with low RAS activity were subjected to hypoglycaemia and euglycaemia in a cross-over study using an intravenous insulin infusion protocol. Cognitive function, electroencephalography, auditory evoked potentials and hypoglycaemic symptoms were recorded.
  
  
  RESULTS
  At a hypoglycaemic nadir of 2.2 (SD 0.3) mmol/L the high RAS group displayed significant deterioration in cognitive performance during hypoglycaemia in the three most complex reaction time tasks. In the low RAS group, hypoglycaemia led to cognitive dysfunction in only one reaction time task. The high RAS group reported lower symptom scores during hypoglycaemia than the low RAS group, suggesting poorer hypoglycaemia awareness.
  
  
  CONCLUSIONS
  High RAS activity is associated with increased cognitive dysfunction and blunted symptoms during mild hypoglycaemia compared to low RAS activity. This may explain why high RAS activity is a risk factor for severe hypoglycaemia in type 1 diabetes.
authors.affiliation: Endocrinology Section, Department of Cardiology and Endocrinology, Hillerød Hospital, Hillerød, Denmark.
authors.forename: Thomas
authors.initials: T
authors.lastname: Høi-Hansen
authors.forename: Ulrik
authors.initials: U
authors.lastname: Pedersen-Bjergaard
authors.forename: Rikke Due
authors.initials: RD
authors.lastname: Andersen
authors.forename: Peter Lommer
authors.initials: PL
authors.lastname: Kristensen
authors.forename: Carsten
authors.initials: C
authors.lastname: Thomsen
authors.forename: Troels
authors.initials: T
authors.lastname: Kjaer
authors.forename: Hans
authors.initials: H
authors.lastname: Høgenhaven
authors.forename: Annelise
authors.initials: A
authors.lastname: Smed
authors.forename: Jens Juul
authors.initials: JJ
authors.lastname: Holst
authors.forename: Flemming
authors.initials: F
authors.lastname: Dela
authors.forename: Frans
authors.initials: F
authors.lastname: Boomsma
authors.forename: Birger
authors.initials: B
authors.lastname: Thorsteinsson
mesh_terms: D000328:Adult; D001786:Blood Glucose / Q000378:metabolism; D003071:Cognition / Q000502:physiology; D003922:Diabetes Mellitus, Type 1 / Q000150:complications / Q000503:physiopathology* / Q000523:psychology*; D004569:Electroencephalography / Q000187:drug effects; D005072:Evoked Potentials, Auditory / Q000187:drug effects; D005260:Female; D006801:Humans; D007003:Hypoglycemia / Q000209:etiology / Q000503:physiopathology*; D007328:Insulin / Q000097:blood; D008297:Male; D008875:Middle Aged; D011597:Psychomotor Performance / Q000502:physiology; D012084:Renin-Angiotensin System / Q000502:physiology*
chemical_list: D001786:Blood Glucose; D007328:Insulin