The hyperosmolar hyperglycemic state (HHS) is the most serious acute hyperglycemic emergency in patients with type 2 diabetes. von Frerichs and Dreschfeld described the first cases of HHS in the 1880s in patients with an “unusual diabetic coma” characterized by severe hyperglycemia and glycosuria in the absence of Kussmaul breathing, with a fruity breath odor or positive acetone test in the urine. Current diagnostic HHS criteria include a plasma glucose level >600 mg/dL and increased effective plasma osmolality >320 mOsm/kg in the absence of ketoacidosis. The incidence of HHS is estimated to be <1% of hospital admissions of patients with diabetes. The reported mortality is between 10 and 20%, which is about 10 times higher than the mortality rate in patients with diabetic ketoacidosis (DKA). Despite the severity of this condition, no prospective, randomized studies have determined best treatment strategies in patients with HHS, and its management has largely been extrapolated from studies of patients with DKA. There are many unresolved questions that need to be addressed in prospective clinical trials regarding the pathogenesis and treatment of pediatric and adult patients with HHS.

OBJECTIVEThe optimal level of glycemic control needed to improve outcomes in cardiac surgery patients remains controversial.RESEARCH DESIGN AND METHODSWe randomized patients with diabetes (n = 152) and without diabetes (n = 150) with hyperglycemia to an intensive glucose target of 100–140 mg/dL (n = 151) or to a conservative target of 141–180 mg/dL (n = 151) after coronary artery bypass surgery (CABG) surgery. After the intensive care unit (ICU), patients received a single treatment regimen in the hospital and 90 days postdischarge. Primary outcome was differences in a composite of complications, including mortality, wound infection, pneumonia, bacteremia, respiratory failure, acute kidney injury, and major cardiovascular events.RESULTSMean glucose in the ICU was 132 ± 14 mg/dL (interquartile range [IQR] 124–139) in the intensive and 154 ± 17 mg/dL (IQR 142–164) in the conservative group (P < 0.001). There were no significant differences in the composite of complications between intensive and conservative groups (42 vs. 52%, P = 0.08). We observed heterogeneity in treatment effect according to diabetes status, with no differences in complications among patients with diabetes treated with intensive or conservative regimens (49 vs. 48%, P = 0.87), but a significant lower rate of complications in patients without diabetes treated with intensive compared with conservative treatment regimen (34 vs. 55%, P = 0.008).CONCLUSIONSIntensive insulin therapy to target glucose of 100 and 140 mg/dL in the ICU did not significantly reduce perioperative complications compared with target glucose of 141 and 180 mg/dL after CABG surgery. Subgroup analysis showed a lower number of complications in patients without diabetes, but not in patients with diabetes treated with the intensive regimen. Large prospective randomized studies are needed to confirm these findings.

Pancreatic β-cells couple the oxidation of glucose to the secretion of insulin. Apart from the canonical KATP-dependent glucose-stimulated insulin secretion (GSIS), there are important KATP-independent mechanisms involving both anaplerosis and mitochondrial GTP (mtGTP). How mtGTP that is trapped within the mitochondrial matrix regulates the cytosolic calcium increases that drive GSIS remains a mystery. Here we have investigated whether the mitochondrial isoform of phosphoenolpyruvate carboxykinase (PEPCK-M) is the GTPase linking hydrolysis of mtGTP made by succinyl-CoA synthetase (SCS-GTP) to an anaplerotic pathway producing phosphoenolpyruvate (PEP). Although cytosolic PEPCK (PEPCK-C) is absent, PEPCK-M message and protein were detected in INS-1 832/13 cells, rat islets, and mouse islets. PEPCK enzymatic activity is half that of primary hepatocytes and is localized exclusively to the mitochondria. Novel 13C-labeling strategies in INS-1 832/13 cells and islets measured substantial contribution of PEPCK-M to the synthesis of PEP. As high as 30% of PEP in INS-1 832/13 cells and 41% of PEP in rat islets came from PEPCK-M. The contribution of PEPCK-M to overall PEP synthesis more than tripled with glucose stimulation. Silencing the PEPCK-M gene completely inhibited GSIS underscoring its central role in mitochondrial metabolism-mediated insulin secretion. Given that mtGTP synthesized by SCS-GTP is an indicator of TCA flux that is crucial for GSIS, PEPCK-M is a strong candidate to link mtGTP synthesis with insulin release through anaplerotic PEP cycling.

Hyperglycaemia in people with and without diabetes admitted to the hospital is associated with a substantial increase in morbidity, mortality, and health-care costs. Professional societies have recommended insulin therapy as the cornerstone of inpatient pharmacological management. Intravenous insulin therapy is the treatment of choice in the critical care setting. In non-intensive care settings, several insulin protocols have been proposed to manage patients with hyperglycaemia; however, meta-analyses comparing different treatment regimens have not clearly endorsed the benefits of any particular strategy. Clinical guidelines recommend stopping oral antidiabetes drugs during hospitalisation; however, in some countries continuation of oral antidiabetes drugs is commonplace in some patients with type 2 diabetes admitted to hospital, and findings from clinical trials have suggested that non-insulin drugs, alone or in combination with basal insulin, can be used to achieve appropriate glycaemic control in selected populations. Advances in diabetes technology are revolutionising day-to-day diabetes care and work is ongoing to implement these technologies (ie, continuous glucose monitoring, automated insulin delivery) for inpatient care. Additionally, transformations in care have occurred during the COVID-19 pandemic, including the use of remote inpatient diabetes management-research is needed to assess the effects of such adaptations.

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