IMPACT OF IMPROVED GLYCEMIC CONTROL ON RATES OF HYPOGLYCEMIA IN INSULIN-DEPENDENT DIABETES-MELLITUS

Increased emphasis on strict glycaemic control of insulin dependent di abetes mellitus (IDDM) in young patients may be expected to cause incr eases in rates of significant hypoglycaemia. To evaluate whether this is the case for a large population based sample of IDDM children and a dolescents rates of severe (coma, convulsion) and moderate (requiring assistance for treatment) hypoglycaemia were studied prospectively ove r a four year period. A total of 709 patients were studied yielding 20 27 patient years of data (mean (SD) age: 12.3 (4.4); range 0-18 years, duration IDDM: 4.9 (3.8) years). Details of hypoglycaemia were record ed at clinic visits every three months when glycated haemoglobin (HbA1 (c)) was also measured. Overall the incidence of severe hypoglycaemia was 7.8 and moderate was 15.4 episodes/100 patient years. Over the fou r years mean (SD) clinic HbA1(c) steadily fell from 10.2 (1.6)% in 199 2 to 8.8 (1.5)% in 1995. In parallel with this there was a dramatic in crease in the rate of hypoglycaemia, especially in the fourth year of the study, when severe hypoglycaemia increased from 4.8 to 15.6 episod es/100 patient years. This increase was particularly marked in younger children (<6 years) in whom severe hypoglycaemia increased from 14.9 to 42.1 episodes/100 patient years in 1995. It is concluded that attem pts to achieve improved metabolic control must be accompanied by effor ts to minimise the effects of significant hypoglycaemia, particularly in the younger age group.