Update on glucose control during and after critical illness

Purpose of review There is a complex bidirectional relationship between critical illness and disordered glucose metabolism. This review aims to provide a comprehensive summary of the recent evidence focused on the relationship between critical illness and disordered glucose metabolism through the distinct phases of prior to, during, and after an acute illness that requires admission to the intensive care unit (ICU). Recent findings Recent data suggest that preexisting glucose metabolism affects the optimal blood glucose target during critical illness, with preliminary data suggesting that glucose targets should be ‘personalized’ based on preexisting glycemia. Because of the close association between critical illness and disordered glucose metabolism, there is a need to optimize glucose monitoring in the ICU with rapid, precise, and cost-efficient measurements at the bedside. Recent studies have evaluated the use of various methodologies, with a focus on the use of near-continuous glucose monitoring. For those patients with preexisting diabetes who survive ICU, nocturnal hypoglycemia may be an unrecognized and important issue when discharged to the ward. There is increasing evidence that patients with high blood glucose during their acute illness, so called ‘stress hyperglycemia’, are at increased risk of developing diabetes in the years following recovery from the inciting event. Critically ill patients with COVID-19 appear at greater risk. Summary There have been important recent insights in the approach to glucose monitoring and glucose targets during critical illness, monitoring and administration of glucose-lowering drugs on discharge from the ICU, and longitudinal follow-up of patients with stress hyperglycemia.