Type 2 diabetes and 1-year mortality in intensive care unit patients

Metformin-associated lactic acidosis: A mini review of pathophysiology, diagnosis and management in critically ill patients

Metformin is a common diabetes drug that may reduce lactate clearance by inhibiting mitochondrial oxidative phosphorylation, leading to metformin-associated lactic acidosis (MALA). As diabetes mellitus is a common chronic metabolic condition found in critically ill patients, pre-existing metformin use can often be found in critically ill patients admitted to the intensive care unit or the high dependency unit. The aim of this narrative mini review is therefore to update clinicians about MALA, and to provide a practical approach to its diagnosis and treatment. MALA in critically ill patients may be suspected in a patient who has received metformin and who has a high anion gap metabolic acidosis, and confirmed when lactate exceeds 5 mmol/L. Risk factors include those that reduce renal elimination of metformin (renal impairment from any cause, histamine-2 receptor antagonists, ribociclib) and excessive alcohol consumption (as ethanol oxidation consumes nicotinamide adenine dinucleotides that are also required for lactate metabolism). Treatment of MALA involves immediate cessation of metformin, supportive management, treating other concurrent causes of lactic acidosis like sepsis, and treating any coexisting diabetic ketoacidosis. Severe MALA requires extracorporeal removal of metformin with either intermittent hemodialysis or continuous kidney replacement therapy. The optimal time to restart metformin has not been well-studied. It is nonetheless reasonable to first ensure that lactic acidosis has resolved, and then recheck the kidney function post-recovery from critical illness, ensuring that the estimated glomerular filtration rate is 30 mL/min/1.73 m2 or better before restarting metformin.

Preadmission Insulin-Treated Type 2 Diabetes Mellitus Patients Had Increased Mortality in Intensive Care Units

AIM

To explore the clinical outcomes among preadmission insulin-treated type 2 diabetes mellitus (T2DM) in intensive care units (ICU).

PATIENTS AND METHODS

In this retrospective observational study, 578 T2DM patients admitted to ICU were recruited from March 2011 to February 2021, which were composed of 528 patients treated with insulin after ICU admission (including 300 preadmission non-insulin-treated and 228 preadmission insulin-treated patients) and 50 patients treated without insulin before and after ICU admission. Clinical outcomes were compared between the groups. Variables of age (± 10 years), gender, blood glucose >10 mmol/l on ICU admission, and original comorbidities were used for matching to get the 1:1 matched cohort. The Kaplan-Meier survival curves were graphed to describe the survival trend and Cox regression analysis was performed to get adjusted hazard ratio (HR).

RESULTS

Compared with the preadmission non-insulin-treated T2DM patients, preadmission insulin-treated T2DM patients had higher incidence of hypoglycemia [14.5% (33/228) vs 8.7% (26/300); p = 0.036]. In the 1:1 matched cohort, the preadmission insulin-treated T2DM patients had significantly increased mortality rate [30.0% (45/150) vs (16.0% (24/150)); adjusted HR, 1.68 (1.01-2.80)] than preadmission non-insulin-treated T2DM patients. Compared with T2DM patients treated without insulin before and after ICU admission, preadmission insulin-treated T2DM patients had higher mortality and longer length of ICU stay (all p < 0.05).

CONCLUSION

Preadmission insulin treatment was associated with increased mortality rate and longer length of ICU stay among T2DM patients in ICU. Preadmission insulin-treated T2DM patients might have worse clinical outcomes when they are critically ill.

Association of Diabetes and Admission Blood Glucose Levels with Short-Term Outcomes in Patients with Critical Illnesses

Background

Association of diabetes and admission glucose on the short-term prognosis in patients with critical illnesses are currently ambiguous. We aimed to determine whether diabetes and admission glucose affects short-term prognosis of critically ill patients.

Methods

We performed a retrospective analysis of data on 46,476 critically ill patients from the critical care database. Association of diabetes with 28-day mortality was assessed by inverse probability weighting based on the propensity score. Smoothing splines and threshold effect analysis were applied to explore the relationship between admission glucose and clinical outcomes.

Results

Of the 33,680 patients enrolled in the study, 8,701 (25.83%) had diabetes. In the main analysis, the 28-day mortality was reduced by 29% (hazard ratio (HR)=0.71, 95% confidence interval (CI) 0.67–0.76) in patients with diabetes compared to those without diabetes. The E-value of 2.17 indicated robustness to unmeasured confounders. Significant interactions were observed for glucose at ICU admission, admission type, and insulin use (Interaction P <0.05). A V-shaped relationship was observed between admission glucose and 28-day mortality in non-diabetic patients, with the lowest 28-day mortality corresponding to a glucose level of 101.75 mg/dl (95% CI 94.64–105.80 mg/dl), and admission hypoglycemia or hyperglycemia should be avoided, especially in patients admitted to the surgical intensive care unit (SICU), cardiac surgery recovery unit (CSRU), and coronary care unit (CCU); for diabetic patients, elevated admission glucose does not appear to be associated with a poor prognosis and perhaps may be beneficial except for CCU and CSRU.

Conclusion

The non-detrimental effect of diabetes on the short-term prognosis of critically ill patients was further confirmed, which would reduce 28-day mortality by approximately 29%. For non-diabetic patients, the admission glucose level corresponding to the lowest 28-day mortality was 101.75 mg/dl (95% CI 94.64–105.80 mg/dl); however, for diabetics, the appropriate admission glucose threshold remains unresolved.

The Danish Intensive Care Database

AIM OF DATABASE

The aim of this database is to improve the quality of care in Danish intensive care units (ICUs) by monitoring key domains of intensive care and to compare these with predefined standards.

STUDY POPULATION

The Danish Intensive Care Database (DID) was established in 2007 and includes virtually all ICU admissions in Denmark since 2005. The DID obtains data from the Danish National Registry of Patients, with complete follow-up through the Danish Civil Registration System.

MAIN VARIABLES

For each ICU admission, the DID includes data on the date and time of ICU admission, type of admission, organ supportive treatments, date and time of discharge, status at discharge, and mortality up to 90 days after admission. Descriptive variables include age, sex, Charlson comorbidity index score, and, since 2010, the Simplified Acute Physiology Score (SAPS) II. The variables are recorded with 90%-100% completeness in the recent years, except for SAPS II score, which is 73%-76% complete. The DID currently includes five quality indicators. Process indicators include out-of-hour discharge and transfer to other ICUs for capacity reasons. Outcome indicators include ICU readmission within 48 hours and standardized mortality ratios for death within 30 days after admission using case-mix adjustment (initially using age, sex, and comorbidity level, and, since 2013, using SAPS II) for all patients and for patients with septic shock.

DESCRIPTIVE DATA

The DID currently includes 335,564 ICU admissions during 2005-2015 (average 31,958 ICU admissions per year).

CONCLUSION

The DID provides a valuable data source for quality monitoring and improvement, as well as for research.

Association of inpatient and outpatient glucose management with inpatient mortality among patients with and without diabetes at a major academic medical center

BACKGROUND

Hospitalized patients with diabetes have experienced a disproportionate reduction in mortality over the past decade.

OBJECTIVE

To examine whether this differential decrease affected all patients with diabetes, and to identify explanatory factors.

DESIGN

Serial, cross-sectional observational study.

SETTING

Academic medical center.

PATIENTS

All adult, nonobstetric patients with an inpatient discharge between January 1, 2000 and December 31, 2010.

MEASUREMENT

We assessed in-hospital mortality; inpatient glycemic control (percentage of hospital days with glucose below 70, above 299, and between 70 and 179 mg/dL, and standard deviation of glucose measurements), and outpatient glycemic control (hemoglobin A1c).

RESULTS

We analyzed 322,938 admissions, including 76,758 (23.8%) with diabetes. Among 54,645 intensive care unit (ICU) admissions, there was a 7.8% relative reduction in the odds of mortality in each successive year for patients with diabetes, adjusted for age, race, payer, length of stay, discharge diagnosis, comorbidities, and service (odds ratio [OR]: 0.923, 95% confidence interval [CI]: 0.906-0.940). This was significantly greater than the 2.6% yearly reduction for those without diabetes (OR: 0.974, 95% CI: 0.963-0.985; P < 0.001 for interaction). In contrast, the greater decrease in mortality among non-ICU patients with diabetes did not reach significance. Results were similar among medical and surgical patients. Among ICU patients with diabetes, the significant decline in mortality persisted after adjustment for inpatient and outpatient glucose control (OR: 0.953, 95% CI: 0.914-0.994).

CONCLUSIONS

Patients with diabetes in the ICU have experienced a disproportionate reduction in mortality that is not explained by glucose control. Potential explanations include improved cardiovascular risk management or advances in therapies for diseases commonly affecting patients with diabetes.

Validation of the peroneal nerve test to diagnose critical illness polyneuropathy and myopathy in the intensive care unit: the multicentre Italian CRIMYNE-2 diagnostic accuracy study

OBJECTIVES

To evaluate the accuracy of the peroneal nerve test (PENT) in the diagnosis of critical illness polyneuropathy (CIP) and myopathy (CIM) in the intensive care unit (ICU). We hypothesised that abnormal reduction of peroneal compound muscle action potential (CMAP) amplitude predicts CIP/CIM diagnosed using a complete nerve conduction study and electromyography (NCS-EMG) as a reference diagnostic standard.

DESIGN

prospective observational study.

SETTING

Nine Italian ICUs.

PATIENTS

One-hundred and twenty-one adult (≥18 years) neurologic (106) and non-neurologic (15) critically ill patients with an ICU stay of at least 3 days.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

PATIENTS underwent PENT and NCS-EMG testing on the same day conducted by two independent clinicians who were blind to the results of the other test. Cases were considered as true negative if both NCS-EMG and PENT measurements were normal. Cases were considered as true positive if the PENT result was abnormal and NCS-EMG showed symmetric abnormal findings, independently from the specific diagnosis by NCS-EMG (CIP, CIM, or combined CIP and CIM). All data were centrally reviewed and diagnoses were evaluated for consistency with predefined electrophysiological diagnostic criteria for CIP/CIM. During the study period, 342 patients were evaluated, 124 (36.3%) were enrolled and 121 individuals with no protocol violation were studied. Sensitivity and specificity of PENT were 100% (95% CI 96.1-100.0) and 85.2% (95% CI 66.3-95.8). Of 23 patients with normal results, all presented normal values on both tests with no false negative results. Of 97 patients with abnormal results, 93 had abnormal values on both tests (true positive), whereas four with abnormal findings with PENT had only single peroneal nerve neuropathy at complete NCS-EMG (false positive).

CONCLUSIONS

PENT has 100% sensitivity and high specificity, and can be used to diagnose CIP/CIM in the ICU.

Validation of the peroneal nerve test to diagnose critical illness polyneuropathy and myopathy in the intensive care unit: the multicentre Italian CRIMYNE-2 diagnostic accuracy study

OBJECTIVES

To evaluate the accuracy of the peroneal nerve test (PENT) in the diagnosis of critical illness polyneuropathy (CIP) and myopathy (CIM) in the intensive care unit (ICU). We hypothesised that abnormal reduction of peroneal compound muscle action potential (CMAP) amplitude predicts CIP/CIM diagnosed using a complete nerve conduction study and electromyography (NCS-EMG) as a reference diagnostic standard.

DESIGN

prospective observational study.

SETTING

Nine Italian ICUs.

PATIENTS

One-hundred and twenty-one adult (≥18 years) neurologic (106) and non-neurologic (15) critically ill patients with an ICU stay of at least 3 days.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

PATIENTS underwent PENT and NCS-EMG testing on the same day conducted by two independent clinicians who were blind to the results of the other test. Cases were considered as true negative if both NCS-EMG and PENT measurements were normal. Cases were considered as true positive if the PENT result was abnormal and NCS-EMG showed symmetric abnormal findings, independently from the specific diagnosis by NCS-EMG (CIP, CIM, or combined CIP and CIM). All data were centrally reviewed and diagnoses were evaluated for consistency with predefined electrophysiological diagnostic criteria for CIP/CIM. During the study period, 342 patients were evaluated, 124 (36.3%) were enrolled and 121 individuals with no protocol violation were studied. Sensitivity and specificity of PENT were 100% (95% CI 96.1-100.0) and 85.2% (95% CI 66.3-95.8). Of 23 patients with normal results, all presented normal values on both tests with no false negative results. Of 97 patients with abnormal results, 93 had abnormal values on both tests (true positive), whereas four with abnormal findings with PENT had only single peroneal nerve neuropathy at complete NCS-EMG (false positive).

CONCLUSIONS

PENT has 100% sensitivity and high specificity, and can be used as a screening test to diagnose CIP/CIM in the ICU.

Risk of acute lung injury/acute respiratory distress syndrome in critically ill adult patients with pre-existing diabetes: a meta-analysis

Background

The impact of pre-existing diabetes on the development of acute lung injury/acute respiratory distress syndrome (ALI/ARDS) in critically ill patients remains unclear. We performed a meta-analysis of cohort studies to evaluate the risk of ALI/ARDS in critically ill patients with and without pre-existing diabetes.

Materials and Methods

We searched PubMed and Embase from the inception to September 2013 for cohort studies assessing the effect of pre-existing diabetes on ALI/ARDS occurrence. Pooled odds ratio (OR) with 95% confidence interval (CI) was calculated using random- or fixed-effect models when appropriate.

Results

Seven cohort studies with a total of 12,794 participants and 2,937 cases of pre-existing diabetes, and 2,457 cases of ALI/ARDS were included in the meta-analysis. A fixed-effects model meta-analysis showed that pre-existing diabetes was associated with a reduced risk of ALI/ARDS (OR 0.66; 95% CI, 0.55–0.80; p<0.001), with low heterogeneity among the studies (I² = 18.9%; p = 0.286). However, the asymmetric funnel plot and Egger's test (p = 0.007) suggested publication bias may exist.

Conclusions

Our meta-analysis suggests that pre-existing diabetes was associated with a decreased risk of ALI/ARDS in critically ill adult patients. However, the result should be interpreted with caution because of the potential bias and confounding in the included studies.

Advanced glycation endproducts in diabetes and diabetic complications

This review presents insights from studies of advanced glycation end products (AGEs) in humans and mice. Although the emphasis is on the effects of exogenous AGEs and the suppression of specific host defense mechanisms, AGEs are also formed intracellularly, where they may contribute to several normal intracellular functions. It is only when the overall levels of AGEs in the extracellular and the intracellular spaces exceeds the ability of the native antioxidant (and AGE) defenses that they pose a problem.

Preadmission metformin use and mortality among intensive care patients with diabetes: a cohort study

Introduction

Metformin has anti-inflammatory and anti-thrombotic effects that may improve the outcome of critical illness, but clinical data are limited. We examined the impact of preadmission metformin use on mortality among intensive care unit (ICU) patients with type 2 diabetes.

Methods

We conducted this population-based cohort study among all persons admitted to the 17 ICUs in Northern Denmark (population approximately 1.8 million). We focused on all patients with type 2 diabetes who were admitted to the ICUs between January 2005 and December 2011. Through individual-level linkage of population-based medical databases, type 2 diabetes was identified using a previously validated algorithm including hospital diagnoses, filled prescriptions for anti-diabetic drugs, and elevated HbA1c levels. Metformin use was identified by filled prescriptions within 90 days before admission. Covariates included surgery, preadmission morbidity, diabetes duration, and concurrent drug use. We computed 30-day mortality and hazard ratios (HRs) of death using Cox regression adjusted for covariates, both overall and after propensity score matching.

Results

We included 7,404 adult type 2 diabetes patients, representing 14.0% of 52,964 adult patients admitted to the ICUs. Among type 2 diabetes patients, 1,073 (14.5%) filled a prescription for metformin as monotherapy within 90 days before admission and 1,335 (18.0%) received metformin in combination with other anti-diabetic drugs. Thirty-day mortality was 17.6% among metformin monotherapy users, 17.9% among metformin combination therapy users, and 25.0% among metformin non-users. The adjusted HRs were 0.80 (95% confidence interval (CI): 0.69, 0.94) for metformin monotherapy users and 0.83 (95% CI: 0.71, 0.95) for metformin combination therapy users, compared to non-users. Propensity-score-matched analyses yielded the same results. The association was evident across most subgroups of medical and surgical ICU patients, but most pronounced in elderly patients and in patients with well-controlled diabetes. Former metformin use was not associated with decreased mortality.

Conclusions

Preadmission metformin use was associated with reduced 30-day mortality among medical and surgical intensive care patients with type 2 diabetes.