Brittle diabetes characterised by recurrent hypoglycaemia

There is little information on the clinical characteristics of "brittle" Type 1 (insulin-dependent) diabetic patients with predominantly hypoglycaemic instability. From a total cohort of 381 brittle diabetic patients from various parts of the United Kingdom, 64 (17%) had life-disrupting instability due to recurrent hospital admissions with hypoglycaemia. Compared to brittle patients with recurrent ketoacidosis (DKA), who comprised 59% of the total, those with recurrent hypoglycaemia were characterised by older mean age (34 +/- 20 v 22 +/- 11 y, p < 0.001), and more equal sex distribution (53% v 71% female, p < 0.05). Patients with "mixed brittleness" (24% of total) were intermediate between the other groups, in terms of both age and female predominance. Physicians in charge of patients with hypoglycaemic brittle diabetes considered psychosocial factors to be frequent underlying causes, though organic conditions such as lost hypoglycaemic warnings and alcohol abuse were also mentioned. Factitious insulin overdose was diagnosed in 3 patients. We conclude that hypoglycaemic brittle diabetes is a small but important sub-group of the overall brittle syndrome. It differs in age and sex distribution from the more common syndrome of recurrent DKA.