The goal of personalized glucose control in the critically ill remains elusive

The Value of Glycemic Gap for Predicting Mortality in ICU in Patients With and Without Diabetes

Objective: Dysglycemia is associated with poor outcomes; the actual status of dysglycemia of critically ill patients with diabetes should refer to background glycemia. We investigated the effect of difference between mean blood glucose and basic blood glucose upon outcomes. Methods: Glycated hemoglobin A1c (HbA1c) was detected within the first 24 h and converted to A1C-derived average glucose (ADAG) by the equation ADAG = [(HbA1c∗28.7) - 46.7]∗18-1; blood glucose measurements were fourth per day during the first 7 days after admission; the mean blood glucose level (Mean), standard deviation (SD), and coefficient of variation (CV) were calculated. GAP were calculated as admission blood glucose and Mean minus ADAG, respectively. Results: Six hundred forty-nine patients were recruited and 428 survived at 28 days; 302 patients with diabetes had greater ADAG, blood glucose at admission (BGadm), Mean, SD, CV, GAP, and hypoglycemia incidences. The GAP between Mean and ADAG had superior predictive power, which was decreased in patients with diabetes and increased in patients without diabetes. GAP7 was related to 28-day mortality; the death risk was decreased in patients with diabetes. Patients with lower GAP tended to survive. Nonsurvivors with diabetes suffered higher rate of hypoglycemia than survivors which was the opposite in patients without diabetes. Conclusion: The glycemic GAP between the mean level of blood glucose within the first 7 days in ICU and ADAG was independently associated with 28-day mortality of critically ill patients, which was different between patients with and without diabetes. Hypoglycemia in patients with diabetes should be a concern.

Association of Relative Dysglycemia With Hospital Mortality in Critically Ill Patients: A Retrospective Study

OBJECTIVES

Relative dysglycemia has been proposed as a clinical entity among critically ill patients in the ICU, but is not well studied. This study aimed to clarify associations of relative hyperglycemia and hypoglycemia during the first 24 hours after ICU admission with in-hospital mortality and the respective thresholds.

DESIGN

A single-center retrospective study.

SETTING

An urban tertiary hospital ICU.

PATIENTS

Adult critically ill patients admitted urgently between January 2016 and March 2022.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Maximum and minimum glycemic ratio (GR) was defined as maximum and minimum blood glucose values during the first 24 hours after ICU admission divided by hemoglobin A1c-derived average glucose, respectively. Of 1700 patients included, in-hospital mortality was 16.9%. Nonsurvivors had a higher maximum GR, with no significant difference in minimum GR. Maximum GR during the first 24 hours after ICU admission showed a J-shaped association with in-hospital mortality, and a mortality trough at a maximum GR of approximately 1.12; threshold for increased adjusted odds ratio for mortality was 1.25. Minimum GR during the first 24 hours after ICU admission showed a U-shaped relationship with in-hospital mortality and a mortality trough at a minimum GR of approximately 0.81 with a lower threshold for increased adjusted odds ratio for mortality at 0.69.

CONCLUSIONS

Mortality significantly increased when GR during the first 24 hours after ICU admission deviated from between 0.69 and 1.25. Further evaluation will necessarily validate the superiority of personalized glycemic management over conventional management.

Association Between Individualized Versus Conventional Blood Glucose Thresholds and Acute Kidney Injury After Cardiac Surgery: A Retrospective Observational Study

OBJECTIVES

This study was designed to compare individualized and conventional hyperglycemic thresholds for the risk of acute kidney injury (AKI) after cardiac surgery.

DESIGN

This was an observational study.

SETTING

The study took place in a single-center tertiary teaching hospital.

PARTICIPANTS

Adult patients who underwent cardiac surgery between January 2012 and November 2021 were enrolled.

MEASUREMENTS AND MAIN RESULTS

Two blood glucose thresholds were used to define intraoperative hyperglycemia. While the conventional hyperglycemic threshold (CHT) was 180 mg/dL in all patients, the individualized hyperglycemic threshold (IHT) was calculated based on the preoperative hemoglobin A1c level. Various metrics of intraoperative hyperglycemia were calculated using both thresholds: any hyperglycemic episode, duration of hyperglycemia, and area above the thresholds. Postoperative AKI associations were compared using receiver operating characteristic curves and logistic regression analysis. Among the 2,427 patients analyzed, 823 (33.9%) developed AKI. The C-statistics of IHT-defined metrics (0.58-0.59) were significantly higher than those of the CHT-defined metrics (all C-statistics, 0.54; all p < 0.001). The duration of hyperglycemia (adjusted odds ratio, 1.09; 95% confidence interval, 1.02-1.16) and area above the IHT (1.003; 1.001-1.004) were significantly associated with the risk of AKI, except for the presence of any hyperglycemic episode. None of the CHT-defined metrics were significantly associated with the risk of AKI.

CONCLUSIONS

Individually defined intraoperative hyperglycemia better predicted postcardiac surgery AKI than universally defined hyperglycemia. Intraoperative hyperglycemia was significantly associated with the risk of AKI only for the IHT. Target blood glucose levels in cardiac surgical patients may need to be individualized based on preoperative glycemic status.

Tight versus liberal blood-glucose control in the intensive care unit: special considerations for patients with diabetes

Stress hyperglycaemia, hypoglycaemia, and diabetes are common in critically ill patients and related to clinical endpoints. To avoid complications related to hypoglycaemia and hyperglycaemia, it is recommended to start insulin therapy for the majority of critically ill patients with persistent blood glucose concentrations higher than 10·0 mmol/L (>180 mg/dL), targeting a range of 7·8-10·0 mmol/L (140-180 mg/dL). However, management and evidence-based targets for blood glucose control are under debate, particularly for patients with diabetes. Recent randomised controlled clinical trials now challenge current recommendations. In this Personal View, we aim to highlight these developments and the important differences between critically ill patients with and without diabetes, taking into account the considerable heterogeneity in this patient group. We critically discuss evidence from prospective randomised controlled trials and observational studies on the safety and efficacy of glycaemic control, specifically in the context of patients with diabetes in intensive care units.

Our Scientific Journey through the Ups and Downs of Blood Glucose Control in the ICU

This article tells the story of our long search for the answer to one question: Is stress hyperglycemia in critically ill patients adaptive or maladaptive? Our earlier work had suggested the lack of hepatic insulin effect and hyperglycemia as jointly predicting poor outcome. Therefore, we hypothesized that insulin infusion to reach normoglycemia, tight glucose control, improves outcome. In three randomized controlled trials (RCTs), we found morbidity and mortality benefit with tight glucose control. Moving from the bed to the bench, we attributed benefits to the prevention of glucose toxicity in cells taking up glucose in an insulin-independent, glucose concentration gradient-dependent manner, counteracted rather than synergized by insulin. Several subsequent RCTs did not confirm benefit, and the large Normoglycemia in Intensive Care Evaluation-Survival Using Glucose Algorithm Regulation, or "NICE-SUGAR," trial found increased mortality with tight glucose control associated with severe hypoglycemia. Our subsequent clinical and mechanistic research revealed that early use of parenteral nutrition, the context of our initial RCTs, had been a confounder. Early parenteral nutrition (early-PN) aggravated hyperglycemia, suppressed vital cell damage removal, and hampered recovery. Therefore, in our next and largest "TGC-fast" RCT, we retested our hypothesis, without the use of early-PN and with a computer algorithm for tight glucose control that avoided severe hypoglycemia. In this trial, tight glucose control prevented kidney and liver damage, though with much smaller effect sizes than in our initial RCTs without affecting mortality. Our quest ends with the strong recommendation to omit early-PN for patients in the ICU, as this reduces need of blood glucose control and allows cellular housekeeping systems to play evolutionary selected roles in the recovery process. Once again, less is more in critical care.

Glucose control and outcomes in diabetic and nondiabetic patients treated with targeted temperature management after cardiac arrest

Hyperglycemia is commonly observed in critically ill patients and postcardiac arrest patients, with higher glucose levels and variability associated with poorer outcomes. In this study, we aim to compare glucose control in diabetic and nondiabetic patients using glycated hemoglobin (HbA1c) levels, providing insights for better glucose management strategies. This retrospective observational study was conducted at Seoul St. Mary's Hospital from February 2009 to May 2022. Blood glucose levels were measured hourly for 48 h after return of spontaneous circulation (ROSC), and a glucose management protocol was followed to maintain arterial blood glucose levels between 140 and 180 mg/dL using short-acting insulin infusion. Patients were categorized into four groups based on diabetes status and glycemic control. The primary outcomes assessed were neurological outcome and mortality at 6 months after cardiac arrest. Among the 332 included patients, 83 (25.0%) had a previous diabetes diagnosis, and 114 (34.3%) had an HbA1c of 6.0% or higher. At least one hyperglycemic episode was observed in 314 patients (94.6%) and hypoglycemia was found in 63 patients (19.0%) during 48 h. After the categorization, unrecognized diabetes was noticed in 51 patients with median HbA1c of 6.3% (interquartile range [IQR] 6.1-6.6). Patients with inadequate diabetes control had the highest initial HbA1c level (7.0%, IQR 6.5-7.8) and admission glucose (314 mg/dL, IQR 257-424). Median time to target glucose in controlled diabetes was significantly shorter with the slowest glucose reducing rate. The total insulin dose required to reach the target glucose level and cumulative insulin requirement during 48 h were different among the categories (p <0.001). Poor neurological outcomes and mortality were more frequently observed in patients with diagnosed diabetes. Occurrence of a hypoglycemic episode during the 48 h after ROSC was independently associated with poor neurologic outcomes (odds ratio [OR] 3.505; 95% confidence interval [CI], 2.382-9.663). Surviving patients following cardiac arrest exhibited variations in glucose hemodynamics and outcomes according to the categories based on their preexisting diabetes status and glycemic condition. Specifically, even experiencing a single episode of hypoglycemia during the acute phase could have an influence on unfavorable neurological outcomes. While the classification did not directly affect neurological outcomes, the present results indicate the need for a customized approach to glucose control based on these categories.

Glucometrics in the first week of critical illness and its association with mortality

OBJECTIVE

Evaluation of glucometrics in the first week of ICU stay and its association with outcomes.

DESIGN

Prospective observational study.

SETTING

Mixed ICU of teaching hospital.

PATIENTS

Adults initiated on insulin infusion for 2 consecutive blood glucose (BG) readings ≥180mg/dL.

MAIN VARIABLES OF INTEREST

Glucometrics calculated from the BG of first week of admission: hyperglycemia (BG>180mg/dL) and hypoglycemia (BG<70mg/dL) episodes; median, standard deviation (SD) and coefficient of variation (CV) of BG, glycemic lability index (GLI), time in target BG range (TIR). Factors influencing glucometrics and the association of glucometrics to patient outcomes analyzed.

RESULTS

A total of 5762 BG measurements in 100 patients of median age 55 years included. Glucometrics: hyperglycemia: 2253 (39%), hypoglycemia: 28 (0.48%), median BG: 169mg/dL (162-178.75), SD 31mg/dL (26-38.75), CV 18.6% (17.1-22.5), GLI: 718.5 [(mg/dL)²/h]/week (540.5-1131.5) and TIR 57% (50-67). Diabetes and higher APACHE II score were associated with higher SD and CV, and lower TIR. On multivariate regression, diabetes (p=0.009) and APACHE II score (p=0.016) were independently associated with higher SD. Higher SD and CV were associated with less vasopressor-free days; lower TIR with more blood-stream infections (BSI). Patients with higher SD, CV and GLI had a higher 28-day mortality. On multivariate analysis, GLI alone was associated with a higher mortality (OR 2.99, p=0.04).

CONCLUSIONS

Glycemic lability in the first week in ICU patients receiving insulin infusion is associated with higher mortality. Lower TIR is associated with more blood stream infections.

Impact of tight blood glucose control within normal fasting ranges with insulin titration prescribed by the Leuven algorithm in adult critically ill patients: the TGC-fast randomized controlled trial

Background

It remains controversial whether critical illness-related hyperglycemia should be treated or not, since randomized controlled trials (RCTs) have shown context-dependent outcome effects. Whereas pioneer RCTs found improved outcome by normalizing blood glucose in patients receiving early parenteral nutrition (PN), a multicenter RCT revealed increased mortality in patients not receiving early PN. Although withholding early PN has become the feeding standard, the multicenter RCT showing harm by tight glucose control in this context has been criticized for its potentially unreliable glucose control protocol. We hypothesize that tight glucose control is effective and safe using a validated protocol in adult critically ill patients not receiving early PN.

Methods

The TGC-fast study is an investigator-initiated, multicenter RCT. Patients unable to eat, with need for arterial and central venous line and without therapy restriction, are randomized upon ICU admission to tight (80–110 mg/dl) or liberal glucose control (only initiating insulin when hyperglycemia >215 mg/dl, and then targeting 180–215 mg/dl). Glucose measurements are performed on arterial blood by a blood gas analyzer, and if needed, insulin is only administered continuously through a central venous line. If the arterial line is no longer needed, glucose is measured on capillary blood. In the intervention group, tight control is guided by the validated LOGIC-Insulin software. In the control arm, a software alert is used to maximize protocol compliance. The intervention is continued until ICU discharge, until the patient is able to eat or no longer in need of a central venous line, whatever comes first. The study is powered to detect, with at least 80% power and a 5% alpha error rate, a 1-day difference in ICU dependency (primary endpoint), and a 1.5% increase in hospital mortality (safety endpoint), for which 9230 patients need to be included. Secondary endpoints include acute and long-term morbidity and mortality, and healthcare costs. Biological samples are collected to study potential mechanisms of organ protection.

Discussion

The ideal glucose target for critically ill patients remains debated. The trial will inform physicians on the optimal glucose control strategy in adult critically ill patients not receiving early PN.

Trial registration

ClinicalTrials.gov NCT03665207. Registered on 11 September 2018.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-022-06709-8.

Is it time to personalise glucose targets during critical illness?

PURPOSE OF REVIEW

Dysglycaemia complicates most critical care admissions and is associated with harm, yet glucose targets, particularly in those with preexisting diabetes, remain controversial. This review will summarise advances in the literature regarding personalised glucose targets in the critically ill.

RECENT FINDINGS

Observational data suggest that the degree of chronic hyperglycaemia in critically ill patients with diabetes attenuates the relationship between mortality and several metrics of dysglycaemia, including blood glucose on admission, and mean blood glucose, glycaemic variability and hypoglycaemia in the intensive care unit. The interaction between acute and chronic hyperglycaemia has recently been quantified with novel metrics of relative glycaemia including the glycaemic gap and stress hyperglycaemia ratio. Small pilot studies provided preliminary data that higher blood glucose thresholds in critically ill patients with chronic hyperglycaemia may reduce complications of intravenous insulin therapy as assessed with biomakers. Although personalising glycaemic targets based on preexisting metabolic state is an appealing concept, the recently published CONTROLLING trial did not identify a mortality benefit with individualised glucose targets, and the effect of personalised glucose targets on patient-centred outcomes remains unknown.

SUMMARY

There is inadequate data to support adoption of personalised glucose targets into care of critically ill patients. However, there is a strong rationale empowering future trials utilising such an approach for patients with chronic hyperglycaemia.

Glycemic control in critically ill patients with or without diabetes

Background

Early randomized controlled trials have demonstrated the benefits of tight glucose control. Subsequent NICE-SUGAR study found that tight glucose control increased mortality. The optimal glucose target in diabetic and nondiabetic patients remains unclear. This study aimed to evaluate the relationship between blood glucose levels and outcomes in critically ill patients with or without diabetes.

Methods

This was a retrospective analysis of the eICU database. Repeat ICU stays, ICU stays of less than 2 days, patients transferred from other ICUs, those with less than 2 blood glucose measurements, and those with missing data on hospital mortality were excluded. The primary outcome was hospital mortality. Generalised additive models were used to model relationship between glycemic control and mortality. Models were adjusted for age, APACHE IV scores, body mass index, admission diagnosis, mechanical ventilation, and use of vasopressor or inotropic agents.

Results

There were 52,107 patients in the analysis. Nondiabetes patients exhibited a J-shaped association between time-weighted average glucose and hospital mortality, while this association in diabetes patients was right-shifted and flattened. Using a TWA glucose of 100 mg/dL as the reference value, the adjusted odds ratio (OR) of TWA glucose of 140 mg/dL was 3.05 (95% confidence interval (CI) 3.03–3.08) in nondiabetes and 1.14 (95% CI 1.08–1.20) in diabetes patients. The adjusted OR of TWA glucose of 180 mg/dL were 4.20 (95% CI 4.07–4.33) and 1.49 (1.41–1.57) in patients with no diabetes and patients with diabetes, respectively. The adjusted ORs of TWA glucose of 80 mg/dL compared with 100 mg/dL were 1.74 (95% CI 1.57–1.92) in nondiabetes and 1.36 (95% CI 1.12–1.66) in patients with diabetes. The glucose ranges associated with a below-average risk of mortality were 80–120 mg/dL and 90–150 mg/dL for nondiabetes and diabetes patients, respectively. Hypoglycemia was associated with increased hospital mortality in both groups but to a lesser extent in diabetic patients. Glucose variability was positively associated with hospital mortality in nondiabetics.

Conclusions

Time-weighted average glucose, hypoglycemia, and glucose variability had different impacts on clinical outcomes in patients with and without diabetes. Compared with nondiabetic patients, diabetic patients showed a more blunted response to hypo- and hyperglycemia and glucose variability. Glycemic control strategies should be reconsidered to avoid both hypoglycemia and hyperglycemia.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12871-022-01769-4.

Novel insights in endocrine and metabolic pathways in sepsis and gaps for future research

Sepsis is defined as any life-threatening organ dysfunction caused by a dysregulated host response to infection. It remains an important cause of critical illness and has considerable short- and long-term morbidity and mortality. In the last decades, preclinical and clinical research has revealed a biphasic pattern in the (neuro-)endocrine responses to sepsis as to other forms of critical illness, contributing to development of severe metabolic alterations. Immediately after the critical illness-inducing insult, fasting- and stress-induced neuroendocrine and cellular responses evoke a catabolic state in order to provide energy substrates for vital tissues, and to concomitantly activate cellular repair pathways while energy-consuming anabolism is postponed. Large randomized controlled trials have shown that providing early full feeding in this acute phase induced harm and reversed some of the neuro-endocrine alterations, which suggested that the acute fasting- and stress-induced responses to critical illness are likely interlinked and benefical. However, it remains unclear whether, in the context of accepting virtual fasting in the acute phase of illness, metabolic alterations such as hyperglycemia are harmful or beneficial. When patients enter a prolonged phase of critical illness, a central suppression of most neuroendocrine axes follows. Prolonged fasting and central neuroendocrine suppression may no longer be beneficial. Although pilot studies have suggested benefit of fasting-mimicking diets and interventions that reactivate the central neuroendocrine suppression selectively in the prolonged phase of illness, further study is needed to investigate patient-oriented outcomes in larger randomized trials.