What is the role of Hemoglobin A1c (HbA1c) in operative clearance?

From the Guidelines

For operative clearance, an A1C level below 8% is recommended, as stated in the most recent guidelines from 2025 1. This recommendation is based on the standards of care in diabetes, which suggest that the A1C goal for elective surgeries should be <8% (<64.0 mmol/L) whenever possible. The importance of glycemic control in the perioperative period is highlighted by the need to balance the risks of hyperglycemia and hypoglycemia, with a blood glucose goal of 100–180 mg/dL (5.6–10.0 mmol/L) within 4 h of the surgery 1. Key considerations for operative clearance include:

• A preoperative risk assessment for people with diabetes who are at high risk for ischemic heart disease and those with autonomic neuropathy or renal failure 1
• The potential need to postpone elective surgeries if the A1C is higher than 8%, although emergent or time-sensitive procedures should not be delayed for this reason 1
• The importance of optimizing perioperative glucose control, rather than delaying surgery to achieve a specific A1C target 1. Overall, the goal is to minimize perioperative complications by achieving good glycemic control, while also considering individual patient factors and the type of surgery.

From the Research

HbA1c Levels for Operative Clearance

• The optimal HbA1c level for operative clearance is not well-established, but studies suggest that levels above 6.1-7.7% may be associated with increased risk of complications and adverse outcomes in diabetic patients undergoing surgery 2, 3, 4, 5.
• A study on diabetic patients undergoing elective cervical spine surgery found that HbA1c levels above 6.1 were associated with decreased odds of achieving minimum clinically important difference (MCID) for Neck Disability Index (NDI) 3.
• Another study on diabetic patients undergoing total joint arthroplasty found that HbA1c levels above 7.7% were associated with increased risk of periprosthetic joint infection (PJI) 5.
• However, a study on glycemic management in the operating room found that there is insufficient evidence to recommend routine preoperative testing or optimal values for HbA1c in elective surgical patients 2.

Thresholds for HbA1c

• Different studies suggest different thresholds for HbA1c, including:
  • 6.1% for decreased odds of achieving MCID for NDI in anterior cervical fusion surgery 3
  • 6.8% for increased odds of reoperation and failure to achieve MCID for NRS-Arm pain in posterior cervical laminectomy and fusion (PCLF) 3
  • 7.7% for increased risk of PJI in total joint arthroplasty 5
• These thresholds may vary depending on the specific surgical procedure and patient population.

Glycemic Control and Surgical Outcomes

• Good glycemic control is important for reducing the risk of complications and adverse outcomes in diabetic patients undergoing surgery 2, 3, 4, 5.
• Studies have shown that optimal perioperative care, including screening at-risk patients, use of preoperative oral hypoglycemics and home insulin, anesthetic type and medication selection, blood glucose testing, and treatment for hyperglycemia, can improve surgical outcomes in diabetic patients 2.