title: High preoperative hemoglobin A1c is a risk factor for surgical site infection after posterior thoracic and lumbar spinal instrumentation surgery.
abstract: BACKGROUND
  Diabetes mellitus (DM) is reported to be a risk factor for surgical site infection (SSI), which is a serious complication after spinal surgery. The effect of DM on SSI after instrumented spinal surgery remains to be clarified. The aim was to elucidate perioperative risk factors for infection at the surgical site after posterior thoracic and lumbar spinal arthrodesis with instrumentation in patients with DM.
  
  
  METHODS
  Consecutive patients who underwent posterior instrumented thoracic and lumbar spinal arthrodesis during the years 2005-2011, who could be followed for at least 1 year after surgery, were included. These included 36 patients with DM (19 males and 17 females; mean age 64.3 years). The patients' medical records were retrospectively reviewed to determine the SSI rate. The characteristics of the DM patients were examined in detail, including the levels of serum glucose and HbA1c, which indicate the level of diabetes control.
  
  
  RESULTS
  Patients with DM had a higher rate of SSI (6 of 36 patients, 16.7 %) than patients without DM (10 of 309 patients, 3.2 %). Although the perioperative serum glucose level did not differ between DM patients that did or did not develop SSI, the preoperative HbA1c value was significantly higher in the patients who developed SSI (7.6 %) than in those who did not (6.9 %). SSI developed in 0.0 % of the patients with controlled diabetes (HbA1c <7.0 %) and in 35.3 % of the patients with uncontrolled diabetes (HbA1c ≥7.0 %).
  
  
  CONCLUSIONS
  DM patients whose blood glucose levels were poorly controlled before surgery were at high risk for SSI. To prevent SSI in DM patients, we recommend lowering the HbA1c to <7.0 % before performing surgery.
authors.affiliation: Department of Orthopaedic Surgery, Keio University School of Medicine, 35 Shinanomachi, Shinjyuku, Tokyo, Japan.
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Hikata
authors.affiliation: Department of Orthopaedic Surgery, Keio University School of Medicine, 35 Shinanomachi, Shinjyuku, Tokyo, Japan.
authors.forename: Akio
authors.initials: A
authors.lastname: Iwanami
authors.affiliation: Department of Orthopaedic Surgery, Keio University School of Medicine, 35 Shinanomachi, Shinjyuku, Tokyo, Japan.
authors.forename: Naobumi
authors.initials: N
authors.lastname: Hosogane
authors.affiliation: Department of Orthopaedic Surgery, Keio University School of Medicine, 35 Shinanomachi, Shinjyuku, Tokyo, Japan.
authors.forename: Kota
authors.initials: K
authors.lastname: Watanabe
authors.affiliation: Department of Orthopaedic Surgery, Keio University School of Medicine, 35 Shinanomachi, Shinjyuku, Tokyo, Japan.
authors.forename: Ken
authors.initials: K
authors.lastname: Ishii
authors.affiliation: Department of Orthopaedic Surgery, Keio University School of Medicine, 35 Shinanomachi, Shinjyuku, Tokyo, Japan.
authors.forename: Masaya
authors.initials: M
authors.lastname: Nakamura
authors.affiliation: Department of Orthopaedic Surgery, Keio University School of Medicine, 35 Shinanomachi, Shinjyuku, Tokyo, Japan.
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Toyama
authors.affiliation: Department of Orthopaedic Surgery, Keio University School of Medicine, 35 Shinanomachi, Shinjyuku, Tokyo, Japan. Electronic address: morio@a5.keio.jp.
authors.forename: Morio
authors.initials: M
authors.lastname: Matsumoto
authors.affiliation: Department of Orthopaedic Surgery, Keiyu Hospital, 3-7-3 Minatomirai, Nishi-ku, Yokohama, Kanagawa, Japan.
authors.forename: Michihiro
authors.initials: M
authors.lastname: Kamata
mesh_terms: D001786:Blood Glucose / Q000378:metabolism; D003920:Diabetes Mellitus / Q000097:blood* / Q000188:drug therapy / Q000453:epidemiology; D005260:Female; D005500:Follow-Up Studies; D006442:Glycated Hemoglobin / Q000378:metabolism*; D006801:Humans; D007004:Hypoglycemic Agents / Q000008:administration & dosage; D015994:Incidence; D007279:Injections, Subcutaneous; D007328:Insulin / Q000008:administration & dosage; D007564:Japan / Q000453:epidemiology; D008159:Lumbar Vertebrae / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D057234:Preoperative Period; D011379:Prognosis; D012189:Retrospective Studies; D012307:Risk Factors; D013122:Spinal Diseases / Q000097:blood / Q000601:surgery*; D013123:Spinal Fusion / Q000009:adverse effects*; D013530:Surgical Wound Infection / Q000097:blood* / Q000453:epidemiology / Q000517:prevention & control; D013904:Thoracic Vertebrae / Q000601:surgery*; D013997:Time Factors
chemical_list: D001786:Blood Glucose; D006442:Glycated Hemoglobin; D007004:Hypoglycemic Agents; D007328:Insulin