Hyperglycaemic crises in adult patients with diabetes mellitus

Diabetic ketoacidosis (DKA) and hyperosmolar nonketotic state (HONK; also referred to, in the USA, as hyperglycaemic hyperosmolar state) are the two most serious, potentially fatal acute metabolic complications of diabetes mellitus. In the USA, the annual incidence rate for DKA ranges from 4.6 to 8 episodes per 1000 patients with diabetes of all ages, and 13.4 per 1000 patients in subjects younger than 30 years old (1). The incidence rate in the USA is comparable to the rates in Europe, with estimates of 13.6 per 1000 patients with type 1 diabetes in the UK (2), and 14.9 per 1000 patients with type 1 diabetes in Sweden (3). In the USA, hospitalization for DKA has risen by more than 30% in the last decade, with DKA accounting for approximately 1 35 000 hospital admissions in 2006 (4). The incidence of HONK is difficult to determine because of the lack of population–based studies and the multiple combined illnesses often found in these patients. In general, it is estimated that the rate of hospital admissions due to HONK is lower than it is for DKA and HONK accounts for less than 1% of all primary diabetic admissions (5). The mortality rate in patients with DKA has significantly decreased in experienced centres since the advent of low-dose insulin and appropriate fluid-/electrolyte-replacement protocols. Among adults with DKA in the USA, the overall mortality rate is less than 1% (4). A trend toward remarkable reduction in mortality from DKA has been reported in Europe as well, with one UK university recording no deaths among 46 patients who were admitted for DKA between 1997 and 1999 (2). The incidence and mortality of DKA remains high in developing countries, owing to socioeconomic factors. For instance, in Nairobi, Kenya, the incidence of DKA was about 80 per 1000 hospitalized diabetic patients in a study reported in 2005, and mortality rate was as high as 30% (6). The mortality rate of patients with HONK remains high even in the developed world, at approximately 11%. The prognosis of both conditions is substantially worsened with increased age, presence of coma, and hypotension (7). Despite threat to life, DKA is also expensive, with estimated annual direct and indirect cost of 2 billion US dollars (8).