Brittle diabetes in the elderly

Severely unstable, or brittle, diabetes can be disruptive to patients, care rs and diabetes care teams. The peak age-group for brittle diabetes is 15-3 0, but there are reports of its occurrence in much older patients. To explo re the characteristics and cause of brittle instability perceived by diabet ologists in elderly patients we circulated a questionnaire to all UK hospit al diabetic clinics for adults. 130 (56%) of 231 replied. Reports were obta ined on 55 patients fulfilling our criteria for 'elderly brittle diabetes'- namely, age greater than or equal to 60 years, on insulin treatment, and ex periencing life-disrupting glycaemic instability of any kind associated wit h frequent or long admissions to hospital. Further information was obtained by a research nurse who visited the relevant clinics. The mean age of patients was 74 years (range 60-89) and 71% were female. Th e brittleness was classed as mixed glycaemic instability in 22 (44%), recur rent ketoacidosis in 16 (29%) and recurrent hypoglycaemia in 15 (27%). In 2 cases there was insufficient information for classification. The diabetes care team judged the brittleness to have multiple origins in two-thirds of the cases: problems with memory or behaviour were rare, and in only 4 cases was deliberate manipulation of therapy considered a possibility. 84% of th e patients were living independently. In younger patients the principal manifestation of brittle diabetes is recu rrent ketoacidosis. The present survey, though possibly subject to ascertai nment bias, indicates that the patterns of instability and their causation may be different in elderly patients. With the growing use of insulin in th e elderly, brittle diabetes is likely to be encountered increasingly often in this age-group.