Incidence and outcome of adults with diabetic ketoacidosis admitted to ICUs in Australia and New Zealand

BACKGROUND: Over the last two decades, there have been several improvements in the management of diabetes. Whether this has impacted on the epidemiology and outcome of diabetic ketoacidosis (DKA) requiring intensive care unit (ICU) admission is unknown. METHOD: This was a retrospective study of 8533 patients with the diagnosis of DKA admitted to 171 ICUs in Australia and New Zealand between 2000–2013 with separate independent analysis of those on established insulin (Group I) or not on insulin (Group NI) at the time of hospitalisation. RESULTS: Of the 8553 patients, 2344 (27 %) were identified as NI. The incidence of ICU admission with DKA progressively increased fivefold from 0.97/100,000 (95 % CI 0.84–1.10) in 2000 to 5.3/100,000 (95 % CI 4.98–5.53) in 2013 (P < 0.0001), with the proportions between I and NI remaining stable. Rising incidences were observed mainly in rural and metropolitan hospitals (P < 0.01). In the first 24 hours in the ICU, mean worst pH increased over the study period from 7.20 ± 0.02 to 7.24 ± 0.01 (P < 0.0001), and mean lowest plasma bicarbonate from 12.1 ± 6.6 to 13.8 ± 6.6 mmol/L (P < 0.0001). In contrast, mean highest plasma glucose decreased from 26.3 ± 14 to 23.2 ± 13.1 mmol/L (P < 0.0001). Hospital mortality was significantly greater in NI as compared to I (2.4 % vs 1.1 %, P > 0.0001). Elevated plasma urea in the first 24 hours (≥25 mmol/L, adjusted odds ratio 20.6 (6.54–65.7), P < 0.0001) was the strongest individual predictor of mortality. CONCLUSIONS: The incidence of ICU admission of patients with DKA in Australia and New Zealand has increased fivefold over the last decade, with a significant proportion of patients not on insulin at presentation. Overall physiological status in the first 24 hours of ICU admission has progressively improved and mortality rates have remained stable. However, DKA patients not on established insulin therapy at presentation had significantly worse outcomes. This notion has epidemiologic, diagnostic and management implications.