The Rationale for Preoperative Glycemic Control in Bariatric Surgery

| March 22, 2010 | 0 Comments

by Adrienne Youdim, MD

Dr. Youdim is Medical Director, Comprehensive Weight Loss Center, Cedars Sinai Medical Center, Los Angeles, California and Assistant Clinical Professor of Medicine, David Geffen School of Medicine, University of California Los Angeles, California.

Bariatric Times. 2010;7(3):22

Dr. Youdim has no financial disclosures relevant to the content of this article.


The incidence of type 2 diabetes increases incrementally with rising body mass index. Bariatric surgery induces remission of diabetes through weight loss and weight independent effects. Studies support the role of strict long-term glycemic control, as reflected by HbA1c, in reducing postoperative complications. A reasonable goal for preoperative glycemic control is a HbA1c of 7.0 or less.

The Centers for Disease Control and Prevention (CDC) has estimated that the rate of diabetes in the United States has reached almost 24 million, which translates to nearly eight percent of the population. Another 57 million people are estimated to have pre-diabetes, a strong risk factor for the development of diabetes.[1] The relationship between type 2 diabetes and obesity is well documented as the incidence increases incrementally with rising body mass index (BMI).[2,3] Bariatric surgery induces remission of type 2 diabetes mellitus both through weight loss and weight-independent effects that are believed to be mediated through the release of incretins as in intestinal bypass procedures.[4] The favorable effects of bariartric surgery have been well established, and recently the American Diabetes Association endorsed bariatric surgery for treatment of type 2 diabetes.[5] It is likely that a greater number of patients with diabetes will be seeking treatment of this disease through bariatric surgery. What are the implications of this potential trend with respect to peri-operative outcomes?

Hyperglycemia has been associated with a higher rate of perioperative complications and adverse outcomes in hospitalized patients. One meta-analysis showed an 18-fold increase in hospital mortality and longer length of stay (9 vs. 4.5 days) in patients with hyperglycemia.[6] Hyperglycemia in the surgical intensive care unit is associated with a four-fold increase in blood stream infections (p<0.05), a 3.5-fold increase in surgical site infections (p<0.05), and increased nosocomial pneumonia and urinary tract infections compared to patients with strict glycemic control.[7] Strict glycemic control in this setting has also been associated with a reduction in mortality by nearly 42 percent.[8] While controversy exits regarding intensive glycemic control in critically ill medical patients, the evidence is still favorable for intensive therapy in patients in the surgical setting.[9]

Long-term glycemic control, as measured by hemoglobin A1c (HbA1c), has been shown to reduce complications related to diabetes.[10] Recent studies have shown that long-term glycemic control is also associated with reduced postoperative infections. In one study of more than 600 veteran affairs patients undergoing noncardiac elective surgery, 20 percent of patients with HbA1c of greater than or equal to seven percent had infectious complications compared to 12 percent of patients with a HbA1c less than seven percent.[11]

While there are no studies assessing the role of long-term glycemic control in patients undergoing bariatric surgery, one study did investigate the association between HbA1c and postoperative complications in patients undergoing elective colorectal surgery. Complications including ileus, stomal necrosis, and infection were found to be more common in patients with HbA1c greater than six percent (OR 2.9) compared to patients with HbA1c of six percent or less.[12] Perhaps these findings can be extrapolated to the bariatric surgery population but further study is warranted.

Recently the American Society for Metabolic and Bariatric Surgery (ASMBS), American Association of Clinical Endocrinologists (AACE), and The Obesity Society published joint medical guidelines for the peri-operative care of bariatric surgery patients. The guidelines state, “achievement of preoperative glycemic control HbA1c less than 7.0 percent …represents a realistic best care outcome.”[13] Given the global evidence supporting the role of peri-operative and long-term glycemic control on post-operative outcomes, we should adhere to this best practice unless studies can support lack of efficacy in the bariatric population.

2008/r080624.htm Accessed on January 22, 2010.
2.    Chan JM, Rimm EB, Colditz GA, et al. Obesity, fat distribution and weight gain as risk factors for clinical diabetes in men. Diabetes Care. 1994;17:961–969.
3.    Colditz GA, Willett WC, Rotnitzky A, Manson JE. Weight gain as a risk factor for clinical diabetes mellitus in woman. Ann Intern Med. 1995;122:481–486.
4.    Cummings DE, Overduin J,  Foster-Schubert KE. Gastric bypass for obesity: mechanisms of weight loss and diabetes resolution. J Clin Endocrinol Metab. 2004;89(6):2608–2615.
5.    American Diabetes Association. Standards of Medical Care in Diabetes—2010. Diabetes Care. 2010;33 Suppl 1:S11–61.
6.    Umpierrez GE, Isaacs SD, Bazargan N, et al. Hyperglycemia: An independent marker of in-hospital mortality in patients with undiagnosed diabetes. J Clin Endocrinol Metab. 2002;87(3):978–982.
7.    Neil G, Perdrizet G. American College of Endocrinology position statement on inpatient diabetes and metabolic control. Endocr Pract. 2004; 10[Suppl 2]:46–52.
8.    Van den Berghe G, Wouters P, Weekers F, et al. Intensive insulin therapy in the critically ill patients. N Engl J Med. 2001;345:1359–1367.
9.    Grisdale DE, Souza R, Van Dam RM. Intensive Insulin therapy and mortality among critically ill patients: a meta-analysis including NICE-SUGAR study data. CMAJ. 2009;180 (8):823–827.
10.    UK Prospective Diabetes Study (UKPDS) Group. Intensive blood-glucose control with sulphonylureas or insulin compared with conventional treatment and risk of complications in patients with type 2 diabetes. Lancet. 1998;352(9131):837–853.
11.    Dronge AS, Perkal, MF, Kancir S, et al. Long-term glycemic control and postoperative infectious complications. Arch Surg. 2006;141:375–380.
12.    Gustafsson UO, Thorell A, Soop M, et al. Haemoglobin A1c as a predictor of postoperative hyperglycaemia and complications after major colorectal surgery. Br J Surg. 2009;96(11):1358–1364.
13.    American Association of Clinical Endocrinologists, The Obesity Society, and American Society for Metabolic & Bariatric Surgery Medical guidelines for clinical practice for the perioperative nutritional, metabolic, and nonsurgical support of the bariatric surgery patient. Endocr Pract. 2008;14 Suppl 1:1–83.

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