[Disglycemia in patients with acute kidney injury in the ICU]

Abstract

Derangements of glucose metabolism are common among critically ill patients. Critical illness- associated hyperglycemia (CIAH) is characterized by raised blood glucose levels in association with an acute event that is reversible after resolution of the underlying disease. CIAH has many causes, such as changes in counter-regulatory hormone status, release of sepsis mediators, insulin resistance, drugs and nutritional factors. It is associated with increased mortality risk. This association appears to be strongly influenced by diabetes mellitus as a comorbidity, suggesting the need for an accurate individualization of glycemic targets according to baseline glycemic status. Hypoglycemia is also very common in this clinical context and it has a negative prognostic impact. Many studies based on intensive insulin treatment protocols targeting normal blood glucose values have in fact documented both an increased incidence of hypoglycemia and an increased mortality risk. Finally, glycemic control in the ICU is made even more complex in the presence of acute kidney injury. On one hand, there is in fact a reduction of both the renal clearance of insulin and of gluconeogenesis by the kidney. On the other hand, the frequent need for renal replacement therapy (dialysis / hemofiltration) may result in an energy intake excess, under the form of citrate, lactate and glucose in the dialysate/reinfusion fluids. With regard to the possible renal protective effects afforded by intensive glycemic control protocols, the presently available evidence does not support a reduction in the incidence of AKI and/or the need for RRT with this approach, when compared with standard glucose control. Thus, the most recent guidelines now suggest higher blood glucose targets (<180 mg/dl or 140-180 mg/dl) than in the past (80-110 mg/dl). Albeit with limited evidence, it seems reasonable to extend these indications also to patients with AKI in the intensive care unit. Further studies are needed in order to better ascertain the effects of dysglycemia on the outcome of patients with AKI.