Influence of Type 2 Diabetes Mellitus and Preoperative Hemoglobin A1c Levels on Outcomes of Liver Transplantation

Impact of preoperative haemoglobin A1c levels on postoperative outcomes in adults undergoing major noncardiac surgery: A systematic review

AIMS

Diabetes is known to increase morbidity and mortality after major surgery. However, literature is conflicting on whether elevated preoperative haemoglobin A1c (HbA1c) levels are associated with worse outcomes following major noncardiac surgery. We aimed to investigate the effect of incremental preoperative HbA1c levels on postoperative outcomes in adults who had undergone major noncardiac surgery.

METHODS

We systematically searched PubMed, EMBASE and the Cochrane Library databases for eligible studies published between January 2012 and July 2023. Randomised controlled trials and observational studies (cohort and case-control studies) which measured HbA1c within 6 months before surgery and compared outcomes between at least three incremental subgroups or analysed HbA1c as a continuous variable were included. The systematic review protocol was registered with PROSPERO (CRD42023391946).

RESULTS

Twenty observational studies investigating outcomes across multiple surgical types were included. Higher preoperative HbA1c levels were associated with increased odds of overall postoperative complications, postoperative acute kidney injury, anastomotic leak, surgical site infections and increased length of stay. Each 1% increase in preoperative HbA1c was associated with increased odds of these complications. No association with reoperations and 30-day mortality was identified. The literature was highly variable with respect to composite major complications, perioperative cardiovascular events, hospital readmissions, postoperative pneumonia and systemic thromboembolism.

CONCLUSIONS

Current evidence suggested that higher preoperative HbA1c levels were associated with increased odds of postoperative complications and extended length of stay in adults undergoing major noncardiac surgery. Further high-quality studies would be needed to quantify the risks posed and determine whether early intervention improves outcomes.

Trends and outcomes of liver transplantation among older recipients in the United States

BACKGROUND

The average age of recipients and donors of liver transplantation (LT) is increasing. Although there has been a change in the indications for LT over the years, data regarding the trends and outcomes of LT in the older population is limited.

AIM

To assess the clinical characteristics, age-related trends, and outcomes of LT among the older population in the United States.

METHODS

We analyzed data from the United Network for Organ Sharing database between 1987-2019. The sample was split into younger group (18-64 years old) and older group (≥ 65 years old).

RESULTS

Between 1987-2019, 155758 LT were performed in the United States. During this period there was a rise in median age of the recipients and percentage of LT recipients who were older than 65 years increased (P < 0.05) with the highest incidence of LT among older population seen in 2019 (1920, 23%). Common primary etiologies of liver disease leading to LT in older patients when compared to the younger group, were non-alcoholic steatohepatitis (16.4% vs 5.9%), hepatocellular carcinoma (14.9% vs 6.9%), acute liver failure (2.5% vs 5.2%), hepatitis C cirrhosis (HCV) (19.2 % vs 25.6%) and acute alcoholic hepatitis (0.13% vs 0.35%). In older recipient group female sex and Asian race were higher, while model for end-stage liver disease (MELD) score and rates of preoperative mechanical ventilation were lower (P < 0.01). Median age of donor, female sex, body mass index (BMI), donor HCV positive status, and donor risk index (DRI) were significantly higher in older group (P < 0.01). In univariable analysis, there was no difference in post-transplant length of hospitalization, one-year, three-year and five-year graft survivals between the two groups. In multivariable Cox-Hazard regression analysis, older group had an increased risk of graft failure during the five-year post-transplant period (hazard ratio: 1.27, P < 0.001). Other risk factors for graft failure among recipients were male sex, African American race, re-transplantation, presence of diabetes, mechanical ventilation at the time of LT, higher MELD score, presence of portal vein thrombosis, HCV positive status, and higher DRI.

CONCLUSION

While there is a higher risk of graft failure in older recipient population, age alone should not be a contraindication for LT. Careful selection of donors and recipients along with optimal management of risk factors during the postoperative period are necessary to maximize the transplant outcomes in this population.

Glycated haemoglobin and the risk of postoperative complications in people without diabetes: a prospective population-based study in UK Biobank

The aim of our study was to clarify the association between glycated haemoglobin (HbA1c ) and postoperative outcomes in people without an existing diagnosis of diabetes. Half a million adults were recruited into the UK Biobank prospective cohort study between March 2006 and October 2010. We divided participants into three groups: no diagnosis of diabetes and HbA1c  < 42 mmol.mol-1 ; no diagnosis of diabetes and elevated HbA1c (≥ 42 mmol.mol-1 with no upper limit); and prevalent diabetes (regardless of HbA1c concentration) at recruitment. We followed up participants by linkage with routinely collected hospital data to determine any surgical procedures undertaken after recruitment and the associated postoperative outcomes. Our main outcome measure was a composite primary outcome of 30-day major postoperative complications and 90-day all-cause mortality. We used logistic regression to estimate the odds of the primary outcome by group. We limited analyses to those who underwent surgery within one year of recruitment (n = 26,653). In a combined effects logistic regression model, participants not known to have diabetes with HbA1c  ≥ 42 mmol.mol-1 had increased odds of the primary outcome (OR [95% CI] 1.43 [1.02-2.02]; p = 0.04), when compared with those without diabetes and HbA1c  < 42 mmol.mol-1 . This effect was attenuated and no longer statistically significant in a direct effects model with adjustment for hyperglycaemia-related comorbidity (OR [95% CI] 1.37 [0.97-1.93]; p = 0.07). Elevated pre-operative HbA1c in people without diabetes may be associated with an increased risk of complications, but the association is likely confounded by end-organ comorbidity. In contrast to previous evidence, our findings suggest that to prevent adverse postoperative outcomes, optimisation of pre-existing morbidity should take precedence over reducing HbA1c in people without diabetes.

Prevalence and risk factors of undiagnosed diabetes mellitus among gastroenterological patients: a HbA1c-based single center experience

BACKGROUND

Diabetes mellitus is a major risk factor for microvascular disease, leading to chronic kidney injury or cardiovascular disease, but there is a tremendous proportion of patients worldwide who suffer from undiagnosed diabetes. Until now, little is known about the prevalence of undiagnosed diabetes in gastroenterology inpatients.

OBJECTIVE

To improve detection of undiagnosed diabetes, a routine screening procedure for gastroenterology inpatients, based on hemoglobin A1c (HbA1c) and fasting plasma glucose (FPG) measurement, was established.

METHODS

We conducted a retrospective analysis of the implemented diabetes screening. Diabetes mellitus was diagnosed according to the guideline of the German Diabetes Association in patients with an HbA1c of ≥6.5% anld/or fasting plasma glucose (FPG) ≥126 mg/dL. Univariate and multivariate analyses were performed to identify independent risk factors for undiagnosed diabetes.

RESULTS

Within a 3-month period, 606 patients were eligible for a diabetes screening. Pre-existing diabetes was documented in 120 patients (19.8 %), undiagnosed diabetes was found in 24 (3.9%), and 162 patients (26.7%) met the definition for prediabetes. Steroid medication use, age, and liver cirrhosis due to primary sclerosing cholangitis (PSC) were identified as risk factors for undiagnosed diabetes.

CONCLUSION

The prevalence of undiagnosed diabetes in gastroenterology inpatients is markedly elevated in comparison to the general population, and a substantial number of inpatients are in a prediabetic status, underlining the need for diabetes screening. In addition to previously described risk factors of patient age and steroid medication use, we identified PSC-related liver cirrhosis (but not liver cirrhosis due to another etiology) as an independent risk factor for undiagnosed diabetes.

A Translational In Vivo and In Vitro Metabolomic Study Reveals Altered Metabolic Pathways in Red Blood Cells of Type 2 Diabetes

Clinical parameters used in type 2 diabetes mellitus (T2D) diagnosis and monitoring such as glycosylated haemoglobin (HbA1c) are often unable to capture important information related to diabetic control and chronic complications. In order to search for additional biomarkers, we performed a pilot study comparing T2D patients with healthy controls matched by age, gender, and weight. By using ¹H-nuclear magnetic resonance (NMR) based metabolomics profiling of red blood cells (RBCs), we found that the metabolic signature of RBCs in T2D subjects differed significantly from non-diabetic controls. Affected metabolites included glutathione, 2,3-bisphophoglycerate, inosinic acid, lactate, 6-phosphogluconate, creatine and adenosine triphosphate (ATP) and several amino acids such as leucine, glycine, alanine, lysine, aspartate, phenylalanine and tyrosine. These results were validated by an independent cohort of T2D and control patients. An analysis of the pathways in which these metabolites were involved showed that energetic and redox metabolism in RBCs were altered in T2D, as well as metabolites transported by RBCs. Taken together, our results revealed that the metabolic profile of RBCs can discriminate healthy controls from T2D patients. Further research is needed to determine whether metabolic fingerprint in RBC could be useful to complement the information obtained from HbA1c and glycemic variability as well as its potential role in the diabetes management.