Association of Preoperative Hemoglobin A1c with In-hospital Mortality Following Valvular Heart Surgery

Heart surgery over two decades: what we have learned about results and changing risks

OBJECTIVES

Using the cardiac surgery database is of high importance in referral centers and can lead to a better quality of care for patients. Tehran Heart Center (THC) is a cardiovascular referral center that was inaugurated in 2001. In this report, we aimed to present the third report of trends in patients' cardiovascular risk factors and surgical procedures from 2002 to 2021 that have been gathered for all THC patients.

METHODS

This serial cross-sectional study was conducted at Tehran Heart Center from 2002 to 2021. All patients undergoing cardiac surgeries were eligible to enter the study (N = 63,974). Those with miscellaneous types of surgeries were excluded (N = 9556). The distribution of cardiac surgeries (including isolated coronary artery bypass graft (CABG), isolated valve, and CABG + valve surgeries) and their respective in-hospital mortality were recorded. Furthermore, 20-year trends in the prevalence of various cardiovascular risk factors (CVRFs) among the following groups were evaluated: a) isolated CABG, b) aortic valve replacement/repair for aortic stenosis (AS/AVR/r), and c) isolated other valve surgeries (IVS).

RESULTS

A total of 54,418 patients (male: 70.7%, age: 62.7 ± 10.8 years) comprised the final study population, with 84.5% prevalence of isolated CABG. Overall, the AS/AVR/r group was in between the CABG and IVS groups concerning CVRFs distribution. Excluding some exceptions for the AS/AVR/r group (in which the small sample size (N = 909) precluded observing a clear trend), all studied CVRFs demonstrated an overall rising trend from 2002 to 2021 in all three groups. Regarding in-hospital mortality, the highest rate was recorded as 4.0% in 2020, while the lowest rate was 2.0% in 2001.

CONCLUSIONS

Isolated CABG remained the most frequent procedure in THC. Notable, increasing trends in CVRFs were observed during this 20-year period and across various types of cardiac surgeries, which highlights the clinical and policy-making implications of our findings.

Predictive power of elevated preoperative HbA1c levels for postoperative atrial fibrillation in patients undergoing isolated coronary artery bypass surgery-Many questions to be asked and many answers to be given

The authors performed a detailed retrospective analysis of diabetic patients undergoing isolated coronary artery bypass graft surgery aiming to investigate the association of the preoperative glycosylated hemoglobin with occurrence of postoperative atrial fibrillation. Although statistical analysis showed a weak relationship between HbA1c values of 9.06% or above and postoperative atrial fibrillation (PoAF), they concluded that serum level of HbA1c could not be used as a predictor for the development of PoAF. But there are many questions to be asked and answers to be found.

Management of Hyperglycemia in Hospitalized Adult Patients in Non-Critical Care Settings: An Endocrine Society Clinical Practice Guideline

BACKGROUND

Adult patients with diabetes or newly recognized hyperglycemia account for over 30% of noncritically ill hospitalized patients. These patients are at increased risk for adverse clinical outcomes in the absence of defined approaches to glycemic management.

OBJECTIVE

To review and update the 2012 Management of Hyperglycemia in Hospitalized Patients in Non-Critical Care Settings: An Endocrine Society Clinical Practice Guideline and to address emerging areas specific to the target population of noncritically ill hospitalized patients with diabetes or newly recognized or stress-induced hyperglycemia.

METHODS

A multidisciplinary panel of clinician experts, together with a patient representative and experts in systematic reviews and guideline development, identified and prioritized 10 clinical questions related to inpatient management of patients with diabetes and/or hyperglycemia. The systematic reviews queried electronic databases for studies relevant to the selected questions. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology was used to assess the certainty of evidence and make recommendations.

RESULTS

The panel agreed on 10 frequently encountered areas specific to glycemic management in the hospital for which 15 recommendations were made. The guideline includes conditional recommendations for hospital use of emerging diabetes technologies including continuous glucose monitoring and insulin pump therapy; insulin regimens for prandial insulin dosing, glucocorticoid, and enteral nutrition-associated hyperglycemia; and use of noninsulin therapies. Recommendations were also made for issues relating to preoperative glycemic measures, appropriate use of correctional insulin, and diabetes self-management education in the hospital. A conditional recommendation was made against preoperative use of caloric beverages in patients with diabetes.

CONCLUSION

The recommendations are based on the consideration of important outcomes, practicality, feasibility, and patient values and preferences. These recommendations can be used to inform system improvement and clinical practice for this frequently encountered inpatient population.

A Systematic Review Supporting the Endocrine Society Clinical Practice Guideline for the Management of Hyperglycemia in Adults Hospitalized for Noncritical Illness or Undergoing Elective Surgical Procedures

CONTEXT

Individuals with diabetes or newly recognized hyperglycemia account for over 30% of noncritically ill hospitalized patients. Management of hyperglycemia in these patients is challenging.

OBJECTIVE

To support development of the Endocrine Society Clinical Practice Guideline for management of hyperglycemia in adults hospitalized for noncritical illness or undergoing elective surgical procedures.

METHODS

We searched several databases for studies addressing 10 questions provided by a guideline panel from the Endocrine Society. Meta-analysis was conducted when feasible. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology was used to assess certainty of evidence.

RESULTS

We included 94 studies reporting on 135 553 patients. Compared with capillary blood glucose, continuous glucose monitoring increased the number of patients identified with hypoglycemia and decreased mean daily blood glucose (BG) (very low certainty). Data on continuation of insulin pump therapy in hospitalized adults were sparse. In hospitalized patients receiving glucocorticoids, combination neutral protamine hagedorn (NPH) and basal-bolus insulin was associated with lower mean BG compared to basal-bolus insulin alone (very low certainty). Data on NPH insulin vs basal-bolus insulin in hospitalized adults receiving enteral nutrition were inconclusive. Inpatient diabetes education was associated with lower HbA1c at 3 and 6 months after discharge (moderate certainty) and reduced hospital readmissions (very low certainty). Preoperative HbA1c level < 7% was associated with shorter length of stay, lower postoperative BG and a lower number of neurological complications and infections, but a higher number of reoperations (very low certainty). Treatment with glucagon-like peptide-1 agonists or dipeptidyl peptidase-4 inhibitors in hospitalized patients with type 2 diabetes and mild hyperglycemia was associated with lower frequency of hypoglycemic events than insulin therapy (low certainty). Caloric oral fluids before surgery in adults with diabetes undergoing surgical procedures did not affect outcomes (very low certainty). Counting carbohydrates for prandial insulin dosing did not affect outcomes (very low certainty). Compared with scheduled insulin (basal-bolus or basal insulin + correctional insulin), correctional insulin was associated with higher mean daily BG and fewer hypoglycemic events (low certainty).

CONCLUSION

The certainty of evidence supporting many hyperglycemia management decisions is low, emphasizing importance of shared decision-making and consideration of other decisional factors.

Impact of preoperative glycometabolic status on outcomes in cardiac surgery: Systematic review and meta-analysis

BACKGROUND

Historically, impaired glucose metabolism has been associated with early and late complicated clinical outcomes after cardiac surgery; however, such a condition is not specific to subjects with diabetes mellitus and involves a larger patient population.

METHODS

Databases were screened (January 2000 to December 2020) to identify eligible articles; studies that evaluated the association between preoperative metabolic status, as assessed by glycosylated hemoglobin levels and clinical outcomes, were considered. The studies were stratified in thresholds by baseline glycosylated hemoglobin level (lower vs higher).

RESULTS

Thirty studies, involving 34,650 patients, were included in the review. In a meta-analysis stratified by glycosylated hemoglobin levels, early mortality was numerically reduced in each threshold comparison and yielded the highest reductions when less than 5.5% versus greater than 5.5% glycosylated hemoglobin levels were compared (risk ratio, 0.39; 95% confidence interval, 0.18-0.84; P = .02). Comparing higher glycosylated hemoglobin threshold values yielded comparable results. Late mortality was reduced with lower levels of glycosylated hemoglobin. Low preoperative glycosylated hemoglobin was associated with the lowest risk of sternal wound infections (risk ratio, 0.50; 95% confidence interval, 0.32-0.80; P = .003 and risk ratio, 0.53; 95% confidence interval, 0.39-0.70; P < .0001) for comparisons of less than 7.5% versus greater than 7.5% and less than 7.0% versus greater than 7.0% glycosylated hemoglobin thresholds, respectively. Additionally, levels of glycosylated hemoglobin lower than 7% were associated with reduced hospital stay, lower risk of stroke/transient ischemic attack (risk ratio 0.53; 95% confidence interval, 0.39-0.70; P < .0001), and acute kidney injury (risk ratio, 0.65; 95% confidence interval, 0.54-0.79; P < .0001).

CONCLUSIONS

Lower levels of glycosylated hemoglobin in patients undergoing cardiac surgery are associated with a lower risk of early and late mortality, as well as in the incidence of postoperative acute kidney injury, neurologic complications, and wound infection, compared with higher levels.