The impact of preoperative glycated hemoglobin (HbA1c) on postoperative complications after elective major abdominal surgery: a meta-analysis

Glycated Haemoglobin (HbA1C) in Cardiac Surgery: A Narrative Review

Background: Perioperative dysglycaemia in cardiac surgery is associated with poor outcomes. Glycaemic variability rather than glucose levels is a predictor of the length of an ICU stay, a rise in creatinine and acute kidney injury after cardiac surgery. Glycated haemoglobin (HbA1C) values correspond closely to average blood glucose levels and cut-off values can be used to define a diabetic and pre-diabetic status. These have been correlated with perioperative events. Methods: In this narrative review, MEDLINE (via PubMed) and the Cochrane Library were used to search for the effects of different preoperative HbA1C levels on the postoperative outcomes after cardiac surgery. HbA1C values correspond closely with average blood glucose levels and cut-off values can be used to define a diabetic and pre-diabetic status; these have been correlated with perioperative events. This narrative review discusses the role of HbA1C in cardiac surgery. Discussion: The scientific data show controversial results: some systematic reviews and randomised control trials demonstrated that a high level of HbA1C seems to be an indicator for postoperative complications in cardiac surgery; other studies dissented and reported that mortality and morbidity cannot be directly attributed to HbA1c levels. Conclusions: The scientific community seems to be in general agreement that high levels of HbA1C are prognostic markers of adverse outcomes post cardiac surgery, but it has also been proved that there could be multiple underlying factors contributing to them.

The Relation of Preoperative HbA1c Level With Intraoperative and Postoperative Complications in Type-2 Diabetic Patients: An Observational Study

Background Perioperative dysglycemia increases morbidity and mortality, particularly among those with diabetes mellitus (DM), and elevated HbA1c levels, reflecting long-term blood glucose, are linked to poor healing and higher infection rates. This study investigates the link between preoperative HbA1c levels and perioperative outcomes in type-2 DM patients. Methodology This prospective observational study was conducted in India between January 2021 and April 2022. Sixty patients aged 18-60 with type-2 DM who underwent elective surgery under general anesthesia (GA) were included; the American Society of Anesthesiologists class >III and patients with severe organ failures were excluded. Participants were divided into two groups: A (HbA1c ≤7.5%) and B (HbA1c >7.5%). Data on preoperative vitals, intraoperative hemodynamics, and postoperative complications were collected. SPSS v23 was used for data analysis; p-value <0.05 was considered significant. Results The mean age of the participants was 48.22 years; males comprised 58.3%. Group A had a higher proportion of oral hypoglycemic agents. Group B showed higher maximum mean blood pressure and intraoperative blood sugar levels at one hour. Postoperatively, Group B had higher glucose levels, more prevalent hyperglycemia, and higher preoperative and postoperative blood urea levels. No significant differences were found in postoperative outcomes like acute kidney injury (AKI), leukocytopenia, leucocytosis, fever, and intensive care admission. Surgical site infection (SSI) incidence was higher in group B, though not statistically significant. Group B had more extended hospital stays. Conclusion Preoperative HbA1c above 7.5% was associated with impaired perioperative glycemic control and higher dysglycemic episodes. Higher preoperative HbA1c was found to be linked to increased postoperative hyperglycemia, AKI, intensive care admissions, and more extended hospital stays, though not statistically significant. SSI incidence was higher, highlighting its importance over preoperative HbA1c.

Multi-Modal Prehabilitation in Thoracic Surgery: From Basic Concepts to Practical Modalities

Over the last two decades, the invasiveness of thoracic surgery has decreased along with technological advances and better diagnostic tools, whereas the patient's comorbidities and frailty patterns have increased, as well as the number of early cancer stages that could benefit from curative resection. Poor aerobic fitness, nutritional defects, sarcopenia and "toxic" behaviors such as sedentary behavior, smoking and alcohol consumption are modifiable risk factors for major postoperative complications. The process of enhancing patients' physiological reserve in anticipation for surgery is referred to as prehabilitation. Components of prehabilitation programs include optimization of medical treatment, prescription of structured exercise program, correction of nutritional deficits and patient's education to adopt healthier behaviors. All patients may benefit from prehabilitation, which is part of the enhanced recovery after surgery (ERAS) programs. Faster functional recovery is expected in low-risk patients, whereas better clinical outcome and shorter hospital stay have been demonstrated in higher risk and physically unfit patients.

Lack of Association of A1C With Postoperative Complications in Children With Type 1 or Type 2 Diabetes

Not meeting recommended A1C targets may be associated with postoperative complications in adults, but there are no studies reporting on the relationship between preoperative A1C and postoperative complications in children with type 1 or type 2 diabetes. The objective of this study was to determine whether elevated A1C levels were associated with an increased incidence of postoperative complications in children with diabetes presenting for elective noncardiac surgery or diagnostic procedures. It found no such association, suggesting no need to delay elective surgery in children with diabetes until A1C is optimized.

[Position statement: surgery and diabetes mellitus (Update 2023)]

This position statement reflects the perspective of the Austrian Diabetes Association concerning the perioperative management of people with diabetes mellitus based on the available scientific evidence. The paper covers necessary preoperative examinations from an internal/diabetological point of view as well as the perioperative metabolic control by means of oral antihyperglycemic and/or insulin therapy.

Prehabilitation in Patients before Major Surgery: A Review Article

The overall outcome of the patient after any surgery is determined not only by the fineness of the surgical procedure but also by preoperative conditioning and postoperative care. Prehabilitation decreases the surgical stress response and increases the preparedness of the patient to undergo planned surgical insult. Preoperatively structured inspiratory muscle exercises, cardiopulmonary fitness program, and planned exercise program for muscles of limbs, back, abdomen, head, and neck allow an overall upliftment of the physiological capacity of the patient to better cope with the surgical stress. Optimization of dietary status by macronutrients, micronutrients, and the nutrients has an impact on augmenting postoperative recovery and shortening the overall hospital stay. Preparing patients for the scheduled surgery and initiating alcohol and smoking cessation programs overhaul the patient's mental health and boost the healing process. This concept of prehabilitation a few weeks before surgery is equally beneficial compared to enhancing operative procedures and postsurgical care.

Keywords

length of stay; mental health; nutrients; preoperative exercise; smoking cessation.

The impact of preoperative glycated hemoglobin (HbA1c) on postoperative complications after elective major abdominal surgery: a meta-analysis

Background

Diabetes is a risk factor for postoperative complications. Previous meta-analyses have shown that elevated glycated hemoglobin (HbA1c) levels are associated with postoperative complications in various surgical populations. However, this is the first meta-analysis to investigate the association between preoperative HbA1c levels and postoperative complications in patients undergoing elective major abdominal surgery.

Methods

PRISMA guidelines were adhered to for this study. Six databases were searched up to April 1, 2020. Primary studies investigating the effect of HbA1c levels on postoperative complications after elective major abdominal surgery were included. Risk of bias and quality of evidence assessments were performed. Data were pooled using a random effects model. Meta-regression was performed to evaluate different HbA1c cut-off values.

Results

Twelve observational studies (25,036 patients) were included. Most studies received a ‘good’ and ‘moderate quality’ score using the NOS and GRADE, respectively. Patients with a high HbA1c had a greater risk of anastomotic leaks (odds ratio [OR]: 2.80, 95% CI [1.63, 4.83], P < 0.001), wound infections (OR: 1.21, 95% CI [1.08, 1.36], P = 0.001), major complications defined as Clavien-Dindo [CD] 3–5 (OR: 2.16, 95% CI [1.54, 3.01], P < 0.001), and overall complications defined as CD 1–5 (OR: 2.12, 95% CI [1.48, 3.04], P < 0.001).

Conclusions

An HbA1c between 6% and 7% is associated with higher risks of anastomotic leaks, wound infections, major complications, and overall postoperative complications. Therefore, guidelines with an HbA1c threshold > 7% may be putting pre-optimized patients at risk. Future randomized controlled trials are needed to explore causation before policy changes are made.