Perioperative Insulin Glargine Dosing Study

A Study of the Relationship Between the Proportional Insulin Glargine Evening Dose and the Perioperative Serum Glucose Values in Patients With Diabetes Undergoing Surgery

The main objective of this study is to compare three strategies of evening insulin glargine dosing to preoperative glucose values in patients with diabetes undergoing surgery to determine which dosing strategies most often achieves the admission target study values of 100-179 mg/dl.

There are no evidence-based guidelines for insulin glargine (Lantus) dosing in the perioperative setting. Insulin glargine provides peakless 24-hour coverage of basal insulin needs for people with both Type 1 and Type 2 diabetes. Insulin glargine may be used as the sole insulin or in combination with other rapid-acting insulin to achieve glycemic control.

Anesthesia literature recommends that blood sugar values on insulin-dependent patients be maintained between 120-180 mg/dl in most surgeries. Symptoms of low blood sugar are undetectable in anesthetized patients, and blood glucose is tested at least hourly. Since patients are still awake and alert toward hypoglycemic symptoms in the preoperative area, the admission target study values are 100-179 mg/dl. Glucose values greater than 200 mg/dl have been associated with increased rates of infection, and exacerbated complications if a major cardiovascular event happens.

Frequently insulin glargine is administered in the evening. Patients who are scheduled for surgery in the morning are asked not to eat or drink after midnight. Some endocrinology experts recommend that all or part of the patient's usual insulin glargine should be given to avoid high blood sugar; however, whenever insulin is given without food, the possibility of low blood sugar exists.

1. Patients in Group 1 will administer 80% of their usual insulin glargine dose.
2. Group 2 patients will contact their own diabetes care physician and follow those recommendations for the dose.
3. Group 3 patients will take 50%, 80%, or 100% of their usual insulin glargine dose. Which of those three percentages will be determined by the midpoint of the patient's usual self-reported fasting blood sugar (FBS) range and whether the patients is also taking a rapid-acting insulin.

Inclusion Criteria:

• Scheduled for Surgical Procedure
• Self Management of Diabetes
• Currently on Evening Insulin Glargine prescribed by Primary Care Physician
• Age 18 or over
• Able to Communicate Clearly over the Phone
• Pre-screened by Anesthesia Department > 48 hours prior to Surgery

Exclusion Criteria:

• On Glucocorticoid Medication
• On Insulin Glargine Dual Dosing or Sliding Scale Regimen
• History of Hypoglycemia Unawareness
• Pregnancy or Lactating Female
• On Insulin Glargine for < 3 months