SLR - July 2014 - Megan Wilder

Stress Hyperglycemia and Surgical Site Infection in Stable Nondiabetic Adults with Orthopaedic Injuries

Reference: Richards JE, Hutchinson J, Mukherjee K, Jahangir AA, Mir HR, Evans JM, Perdue AM, OBremskey WT, Sethi MK, May AK. Journal of Trauma and Acute Care Surgery. 2014 April; 76 (4): 1070-1075.

Scientific Literature Review

Reviewed By: Megan L. Wilder, DPM 
Residency Program: Franciscan Foot and Ankle Institute, Federal Way, WA

Podiatric Relevance: Podiatric physicians are all too familiar with addressing hyperglycemia and healing complications in patients with diabetes. However, the concept of addressing hyperglycemia in nondiabetic patients with orthopaedic injuries is a not a concept typically addressed in the podiatric literature. Nearly one third of patients who are admitted to the hospital have hyperglycemia in the absence of diabetes. Elevated perioperative blood glucose levels in general surgery patients have been shown to increase the risk of postoperative infections, independent of diabetes. The present study is a prospective study that evaluates the relationship between surgical site infection and hyperglycemia in stable nondiabetic patients, with the hypothesis that that hyperglycemia is associated with an increased risk of a 30-day surgical site infection requiring reoperation.

Methods: This study is a Level III prospective observational cohort study performed at a Level 1 trauma center over a time span of nine months. Inclusion criteria were patients over age 18 with surgical orthopaedic injuries. The study excluded patients with diabetes, corticosteroid use, multisystem injuries, or critical illness. Demographics, American Society of Anesthesiologists classification status (ASA), medical comorbidities, BMI, open fracture classification, and number of operations were recorded. Finger stick glucose measurements were obtained twice daily. Hyperglycemia was defined as a fasting glucose greater than or equal to 125 mg/dL or a random value greater than or equal to 200 mg/dL on more than one occasion prior to a diagnosis of a surgical site infection. A surgical site infection was defined as a positive intraoperative culture at reoperation within 30 days of the index case. Superficial infections requiring only oral or topical antibiotics were not included.

Results: One hundred seventy-one patients were enrolled in the study, 40 (23.4 percent) were hyperglycemic; seven of them were excluded for occult diabetes. Hyperglycemic patients underwent glycosylated hemoglobin level testing. Those who measured 6.0 or greater were considered to be occult diabetic patients and were excluded. Thirty-three (20.1 percent) of the remaining 164 patients were hyperglycemic, 50 had open fractures (6 Type I, 22 Type II, 22 Type III), and 12 (7.3 percent) had a surgical site infection. Hyperglycemic patients were more likely to develop a surgical site infection; 7 of 33 (21.2 percent) versus 5 of 131 (3.8 percent), p=0.003. Open fractures were associated with a surgical site infection; seven of 50 (14 percent) versus 5 of 114 (4.4 percent), p=0.047. Open fractures were not associated with hyperglycemia; 10 of 50 (20.0 percent) versus 23 of 114 (20.2 percent), p=0.98. There was no significant difference between infected and non-infected patients in regards to demographics, ASA, comorbidities, BMI, tobacco use, or number of operations.

Conclusions: This prospective cohort study of stable, nondiabetic patients showed a significant association between stress hyperglycemia and surgical site infections in orthopaedic trauma. Further studies are needed to identify optimal management and treatment of hyperglycemia in the nondiabetic stable orthopedic trauma population. This study could influence the way we preoperatively manage our trauma patients, perhaps highlighting the need for routine blood glucose monitoring in all trauma patients regardless of diabetes status. At the very least, this study influences the way in which we counsel patients on their post-operative risk of infection following orthopaedic trauma. 

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