The paradox of the glycemic gap: Does relative hypoglycemia exist in critically ill patients?

The association between acute kidney injury and dysglycaemia in critically ill patients with and without diabetes mellitus: a retrospective single-center study

BACKGROUND

Critically ill patients in the intensive care unit (ICU) often experience dysglycaemia. However, studies investigating the link between acute kidney injury (AKI) and dysglycaemia, especially in those with and without diabetes mellitus (DM), are limited.

METHODS

We used the Medical Information Mart for Intensive Care IV database to investigate the association between AKI within 7 days of admission and subsequent dysglycaemia. The primary outcome was the occurrence of dysglycaemia (both hypoglycemia and hyperglycemia) after 7 days of ICU admission. Logistic regression analyzed the relationship between AKI and dysglycaemia, while a Cox proportional hazards model estimated the long-term mortality risk linked to the AKI combined with dysglycaemia.

RESULTS

A cohort of 20,008 critically ill patients were included. The AKI group demonstrated a higher prevalence of dysglycaemia, compared to the non-AKI group. AKI patients had an increased risk of dysglycaemia (adjusted odds ratio [aOR] 1.53, 95% confidence interval [CI] 1.41-1.65), hypoglycemia (aOR 1.56, 95% CI 1.41-1.73), and hyperglycemia (aOR 1.53, 95% CI 1.41-1.66). In subgroup analysis, compared to DM patients, AKI showed higher risk of dysglycaemia in non-DM patients (aOR: 1.93 vs. 1.33, Pint<0.01). Additionally, the AKI with dysglycaemia group exhibited a higher risk of long-term mortality compared to the non-AKI without dysglycaemia group. Dysglycaemia also mediated the relationship between AKI and long-term mortality.

CONCLUSION

AKI was associated with a higher risk of dysglycaemia, especially in non-DM patients, and the combination of AKI and dysglycaemia was linked to higher long-term mortality. Further research is needed to develop optimal glycemic control strategies for AKI patients.

The glycemic gap as a prognostic indicator in cardiogenic shock: a retrospective cohort study

BACKGROUND

Stress-induced hyperglycemia (SIH) is associated with poor outcomes in cardiogenic shock (CS), and there have been inconsistent results among patients with or without diabetes mellitus (DM). The glycemic gap (GG) is derived by subtracting A1c-derived average glucose from blood glucose levels; it is a superior indicator of SIH. We aimed to explore the role of GG in the outcomes of patients with CS.

METHODS

Data on patients diagnosed with CS were extracted from the MIMIC-IV v2.0 database to investigate the relationship between GG and 30-day mortality (Number of absolute GG subjects = 359; Number of relative GG subjects = 357). CS patients from the Second Affiliated Hospital of Wenzhou Medical University were enrolled to explore the correlation between GG and lactic acid (Number of absolute GG subjects = 252; Number of relative GG subjects = 251). Multivariate analysis, propensity score-matched (PSM) analysis, inverse probability treatment weighting (IPTW), and Pearson correlation analysis were applied.

RESULTS

Absolute GG was associated with 30-day all-cause mortality in CS patients (HRadjusted: 1.779 95% CI: 1.137-2.783; HRPSM: 1.954 95% CI: 1.186-3.220; HRIPTW: 1.634 95% CI: 1.213-2.202). The higher the absolute GG level, the higher the lactic acid level (βadjusted: 1.448 95% CI: 0.474-2.423). A similar trend existed in relative GG (HRadjusted: 1.562 95% CI: 1.003-2.432; HRPSM: 1.790 95% CI: 1.127-2.845; HRIPTW: 1.740 95% CI: 1.287-2.352; βadjusted:1.294 95% CI: 0.369-2.219). Subgroup analysis showed that the relationship existed irrespective of DM. The area under the curve of GG combined with the Glasgow Coma Scale (GCS) for 30-day all-cause mortality was higher than that of GCS (absolute GG: 0.689 vs. 0.637; relative GG: 0.688 vs. 0.633). GG was positively related to the triglyceride-glucose index. Kaplan-Meier curves revealed that groups of higher GG with DM had the worst outcomes. The outcomes differed among races and GG levels (all P < 0.05).

CONCLUSIONS

Among patients with CS, absolute and relative GGs were associated with increased 30-day all-cause mortality, regardless of DM. The relationship was stable after multivariate Cox regression analysis, PSM, and IPTW analysis. Furthermore, they reflect the severity of CS to some extent. Hyperlactatemia and insulin resistance may underlie the relationship between stress-induced hyperglycemia and poor outcomes in CS patients. They both improve the predictive efficacy of the GCS.

Association of glycemic gap with stroke recurrence in patients with ischemic stroke

BACKGROUND

Glycemic gap, as a novel index of acute glycemic excursion, is associated with poor prognosis of different diseases. This study aimed to explore the association of the glycemic gap with long-term stroke recurrence in patients with ischemic stroke.

METHODS

This study included patients with ischemic stroke from the Nanjing Stroke Registry Program. The glycemic gap was calculated by subtracting the estimated average blood glucose from the blood glucose at admission. Multivariable Cox proportional hazards regression analysis was performed to explore the association between the glycemic gap and the risk of stroke recurrence. The Bayesian hierarchical logistic regression model was used to estimate the effects of the glycemic gap on stroke recurrence stratified by diabetes mellitus and atrial fibrillation.

RESULTS

Among 2734 enrolled patients, 381 (13.9%) patients experienced stroke recurrence during a median follow-up of 3.02 years. In multivariate analysis, glycemic gap (high group vs. median group) was associated with significantly increased risk for stroke recurrence (adjusted hazard ratio, 1.488; 95% confidence interval, 1.140-1.942; p = .003) and had varying effects on stroke recurrence depending on atrial fibrillation. The restricted cubic spline curve showed a U-shaped relationship between the glycemic gap and stroke recurrence (p = .046 for nonlinearity).

CONCLUSION

Our study found that the glycemic gap was significantly associated with stroke recurrence in patients with ischemic stroke. The glycemic gap was consistently associated with stroke recurrence across subgroups and had varying effects depending on atrial fibrillation.

Glycemic Gap Predicts Mortality in a Large Multicenter Cohort Hospitalized With COVID-19

CONTEXT

Diabetes or hyperglycemia at admission are established risk factors for adverse outcomes during hospitalization for COVID-19, but the impact of prior glycemic control is not clear.

OBJECTIVE

We aimed to examine the associations between admission variables, including glycemic gap, and adverse clinical outcomes in patients hospitalized with COVID-19 infection.

METHODS

We examined the relationship between clinical predictors, including acute and chronic glycemia, and clinical outcomes, including intensive care unit (ICU) admission, mechanical ventilation (MV), and mortality among 1786 individuals with diabetes or hyperglycemia (glucose > 10 mmol/L twice in 24 hours) who were admitted from March 2020 through February 2021 with COVID-19 infection at 5 university hospitals in the eastern United States.

RESULTS

The cohort was 51.3% male, 53.3% White, 18.8% Black, 29.0% Hispanic, with age = 65.6 ± 14.4 years, BMI = 31.5 ± 7.9 kg/m2, glucose = 12.0 ± 7.5 mmol/L [216 ± 135 mg/dL], and HbA1c = 8.07% ± 2.25%. During hospitalization, 38.9% were admitted to the ICU, 22.9% received MV, and 10.6% died. Age (P < 0.001) and admission glucose (P = 0.014) but not HbA1c were associated with increased risk of mortality. Glycemic gap, defined as admission glucose minus estimated average glucose based on HbA1c, was a stronger predictor of mortality than either admission glucose or HbA1c alone (OR = 1.040 [95% CI: 1.019, 1.061] per mmol/L, P < 0.001). In an adjusted multivariable model, glycemic gap, age, BMI, and diabetic ketoacidosis on admission were associated with increased mortality, while higher estimated glomerular filtration rate (eGFR) and use of any diabetes medication were associated with lower mortality (P < 0.001).

CONCLUSION

Relative hyperglycemia, as measured by the admission glycemic gap, is an important marker of mortality risk in COVID-19.

Factors Associated With Discordant A1C-Estimated and Measured Average Glucose Among Hospitalized Patients With Diabetes

In this retrospective analysis, we explored the correlation between measured average glucose (mAG) and A1C-estimated average glucose (eAG) in hospitalized patients with diabetes and identified factors associated with discordant mAG and eAG at the transition from home to hospital. Having mAG lower than eAG was associated with Black race, other race, increasing length of stay, community hospital setting, surgery, fever, metformin use, certain inpatient diets, home antihyperglycemic treatment, and coded type 1 or type 2 diabetes. Having mAG higher than eAG was associated with certain discharge services (e.g., intensive care unit), higher BMI, hypertension, tachycardia, higher albumin, higher potassium, anemia, inpatient glucocorticoid use, and treatment with home insulin, secretagogues, and glucocorticoids. These factors should be considered when using patients' A1C as an indicator of outpatient glycemic control to determine the inpatient antihyperglycemic regimens.

Type 2 Diabetes Mellitus with Tight Glucose Control and Poor Pre-Injury Stair Climbing Capacity May Predict Postoperative Delirium: A Secondary Analysis

(1) Background: Previous evidence demonstrates that tight glycemic control and good physical function could reduce the risk of delirium. This study aimed to investigate whether the occurrence of postoperative delirium (POD) in older hip fracture surgery patients is associated with preoperative glycemic control factors or pre-injury physical performance. (2) Methods: Three-hundred and nine individuals aged over 65 years and scheduled for hip fracture surgery were included at a single center. Glycemic control factors and pre-injury physical performance were assessed preoperatively. The presence of delirium was assessed using the Confusion Assessment Method on postoperative hospitalization days. Univariate and multivariable logistic regression models and a risk prediction model of POD were established. (3) Results: Among the 309 patients, 52 (16.83%) experienced POD during the hospital stay. The numbers of pre-injury physical performance and type 2 diabetes mellitus (T2DM) patients were significantly different in the POD and non-POD groups. The multivariable model showed that development of delirium was significantly explained by preoperative fasting blood glucose (FBG) (OR 0.804, p = 0.004), stair climbing (OR 0.709, p = 0.003), T2DM (odds ratio (OR) 3.654, p = 0.001), and age-adjusted Charlson comorbidity index (ACCI) (OR 1.270, p = 0.038). The area under the receiver operating characteristic curve (AUROC) of the risk prediction model including those covariates was 0.770. (4) Conclusions: More older T2DM patients develop POD after hip fracture surgery than patients without T2DM. A simple assessment of preoperative FBG and pre-injury stair climbing capacity may identify those at high risk for the development of POD. Higher preoperative FBG and good pre-injury stair climbing capacity are protective factors for POD.

Association between time in range of relative normoglycemia and in-hospital mortality in critically ill patients: a single-center retrospective study

The aim of this single-center retrospective study was to investigate the association between the time in range (TIR) of relative normoglycemia (RN) and in-hospital mortality. We defined RN as measured blood glucose in the range of 70–140% of A1C-derived average glucose and absolute normoglycemia (AN) as 70–140 mg/dL. We conducted multivariate logistic regression analyses to examine the association between TIR of RN > 80% or TIR of AN > 80% up to 72 h after ICU admission and in-hospital mortality (Model 1 and Model 2, respectively). The discrimination of the models was assessed using the area under the receiver operating characteristic curve (AUROC). Among 328 patients, 35 died in hospital (11%). Model 1 showed that TIR of RN > 80% was associated with reduced in-hospital mortality (adjusted OR 0.16; 95% CI 0.06–0.43; P < 0. 001); however, Model 2 showed that the TIR of AN > 80% was not. The AUROC of Model 1 was significantly higher than that of Model 2 (0.84 [95% CI 0.77–0.90] vs. 0.79 [0.70–0.87], P = 0.008).Our findings provide a foundation for further studies exploring individualized glycemic management in ICUs.

Association between stress hyperglycemia on admission and unfavorable neurological outcome in OHCA patients receiving ECPR

BACKGROUND

Stress hyperglycemia is a normal response to stress and has been associated with outcomes in out-of-hospital cardiac arrest (OHCA) patients. However, this association remained unknown in OHCA patients receiving extracorporeal cardiopulmonary resuscitation (ECPR). This study aimed to examine the association between degree of stress hyperglycemia on admission and neurological outcomes at discharge in OHCA patients receiving ECPR.

PATIENTS AND METHODS

This was a retrospective cohort study of adult OHCA patients receiving ECPR between 2011 and 2021. Patients were classified into three groups: absence of stress hyperglycemia (blood glucose level on admission < 200 mg/dL), moderate stress hyperglycemia (200-299 mg/dL), and severe stress hyperglycemia (≥ 300 mg/dL). The primary outcome was unfavorable neurological outcome (Cerebral Performance Category: 3-5) at discharge.

RESULTS

This study included 160 patients; unfavorable neurological outcomes totaled 79.4% (n = 127). There were 23, 52, and 85 patients in the absence, moderate, and severe stress hyperglycemia groups, respectively. Of each group, unfavorable neurological outcomes constituted 91.3%, 71.2%, and 81.2%, respectively. Multivariable analysis showed that, compared with moderate stress hyperglycemia, absence of stress hyperglycemia on admission was significantly associated with unfavorable neurological outcome at discharge (odds ratio [OR], 4.70; 95% confidence interval [CI], 1.07-33.35; p = 0.039).

CONCLUSION

Compared with moderate stress hyperglycemia on admission, absence of stress hyperglycemia showed significant association with unfavorable neurological outcome at discharge in OHCA patients receiving ECPR.

Insulin therapy associated relative hypoglycemia during critical illness

PURPOSE

In critically ill diabetes patients, relative hypoglycemia (RH) (a decrease in glucose ≥30% below pre-admission levels, as estimated by HbA1c) is associated with greater mortality and absolute hypoglycemia. We investigated the epidemiology and outcomes of RH when it was associated with insulin therapy.

METHODS

We performed retrospective analysis of a cohort of critically ill patients with diabetes who received insulin in the intensive care units (ICUs) of a tertiary hospital. The primary outcome was 28-day mortality with respect to insulin therapy associated relative hypoglycemia (ITARH).

RESULTS

ITARH occurred in 184 (42%) of insulin-treated patients. ITARH was associated with a higher HbA1c (8.6% vs 6.6%, p < 0.001), a higher glycemic variability index (121 vs 75.1 mmol²/L²/h/week, p < 0.001) and more absolute hypoglycemia (18.5% vs 3.94%, p < 0.001). Its frequency peaked about 5 h after initiation of insulin therapy. ITARH was associated with a greater risk of subsequent hypoglycemia (adjusted HR 3.5, 95% CI 1.7-6.8) but not mortality (HR 1.2, 95% CI 0.7-2.2).

CONCLUSIONS

ITARH is common in insulin treated critically ill diabetes patients and associated with poorer glycemic control. Unlike reports of RH in general, it is not associated with mortality, suggesting that the prognostic implications of RH differ according to its context.

Paradox of trimethylamine-N-oxide, the impact of malnutrition on microbiota-derived metabolites and septic patients

Background

Trimethylamine N-oxide (TMAO) is a microbiota-derived metabolite, which is linked to vascular inflammation and atherosclerosis in cardiovascular (CV) diseases. But its effect in infectious diseases remains unclear. We conducted a single-center prospective study to investigate association of TMAO with in-hospital mortality in septic patients admitted to an intensive care unit (ICU).

Methods

Totally 95 septic, mechanically ventilated patients were enrolled. Blood samples were obtained within 24 h after ICU admission, and plasma TMAO concentrations were determined. Septic patients were grouped into tertiles according to TMAO concentration. The primary outcome was in-hospital death, which further classified as CV and non-CV death. Besides, we also compared the TMAO concentrations of septic patients with 129 non-septic patients who were admitted for elective coronary angiography (CAG).

Results

Septic patients had significantly lower plasma TMAO levels than did subjects admitted for CAG (1.0 vs. 3.0 μmol/L, p < 0.001). Septic patients in the lowest TMAO tertile (< 0.4 μmol/L) had poorer nutrition status and were given longer antibiotic courses before ICU admission. Circulating TMAO levels correlated positively with daily energy intake, the albumin and prealbumin concentration. Compared with those in the highest TMAO tertile, septic patients in the lowest TMAO tertile were at greater risk of non-CV death (hazard ratio 2.51, 95% confidence interval 1.21–5.24, p = 0.014). However, TMAO concentration was no longer an independent predictor for non-CV death after adjustment for disease severity and nutritional status.

Conclusion

Plasma TMAO concentration was inversely associated with non-CV death among extremely ill septic patients, which could be characterized as TMAO paradox. For septic patients, the impact of malnutrition reflected by circulating TMAO levels was greater than its pro-inflammatory nature.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40560-021-00581-5.