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Preoperative HbA1c predicts mortality after vascular surgery

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December 7, 2018

Long-term mortality risk may be indicated by HbA1c levels before surgery in adults who undergo surgical treatment for peripheral artery disease, according to findings published in the Journal of Diabetes.

Iren D. Hjellestad

“HbA1c should be included as a risk marker when assessing a preoperative risk profile in vascular surgery patients,” Iren D. Hjellestad, MD, a specialist in internal medicine at the department of laboratory medicine and pathology at Haukeland University Hospital in Norway, and Torbjørn Jonung, MD, Dr.Med, professor in emeritus of vascular surgery at the department of clinical sciences at the University of Bergen in Norway, told Endocrine Today. “Patients with elevated HbA1c should be considered for a close follow-up and treatment aiming at risk factor control. This may add as a step towards precision medicine for vascular surgery patients.”

Hjellestad, Jonung and colleagues conducted an exploratory prospective cohort study with 273 participants who were admitted for vascular surgery due to atherosclerotic disease at Haukeland University Hospital in Norway between October 2006 and September 2007. All participants had unknown glycemic status when they were admitted. HbA1c, fasting plasma glucose and 2-hour post-load glucose measurements were taken for all participants, who were followed until August 2016. All-cause mortality was determined based on data from the Norwegian civil registry.

Torbjørn Jonung

In total, the rate of all-cause mortality was 40%, with 110 deaths in the cohort. The rate of mortality was 79% for participants with diagnosed diabetes. The researchers noted that higher mean HbA1c levels were recorded in participants who died during the study compared with those who did not (6.2% vs. 6%; P = .003). Additionally, a diabetes diagnosis based on HbA1c was associated with a higher rate of mortality vs. participants with normal HbA1c (P = .015). Significance remained when adjusting for age, sex and use of platelet inhibitors, statins and antihypertensive medication (P = .04), but not when fully adjusted in a Cox regression model (P = .13). In comparison, FPG and 2-hour post-load glucose did not predict mortality significantly in all three models, according to the researchers.

“Oral glucose tolerance test and HbA1c values represent different metabolic expressions. The OGTT is a stress test of pancreatic islet cell functioning, whereas HbA1c represents long-term exposure to plasma glucose,” the researchers wrote. “Sustained hyperglycemia may induce non-enzymatic glycation of lipoproteins and thereby start a cascade of changes in the endothelial cells that may lead to endothelial dysfunction. Thus, HbA1c may, to a greater extent than OGTT results, express the degree of macro- and microvascular inflammation. This could possibly explain the association between HbA1c and all-cause mortality in the present study.” – by Phil Neuffer

For more information:

Iren D. Hjellestad, MD, can be reached at Haukeland University Hospital, Jonas Lies vei 65, 5021 Bergen, Norway; email: iren.hjellestad@gmail.com

Disclosures: The authors report no relevant financial disclosures.