title: Glycosylated hemoglobin levels and outcome in non-diabetic cardiac surgery patients.
abstract: OBJECTIVE
  In diabetics, elevated preoperative hemoglobin A1c (HbA1c) levels are associated with increased complication rates after cardiac surgery. While many non-diabetics also have elevated HbA1c, the relationship with outcome in these patients is not well understood. Therefore, in a cohort of non-diabetic patients, we tested the hypothesis that preoperative HbA1c is associated with early mortality risk after cardiac surgery.
  
  
  METHODS
  In this retrospective observational study, we accessed data from a prospectively collected quality assurance database for a cohort of 1,474 non-diabetic elective cardiac surgery patients with documented preoperative HbA1c levels. The relationship of HbA1c with death within 30 days of surgery was examined using logistic regression modeling. Acute kidney injury and infection were similarly assessed using multivariable linear and logistic regression.
  
  
  RESULTS
  Thirty-one percent of patients (n = 456) had elevated HbA1c values (>6.0%). Patients with elevated HbA1c had higher fasting and peak intraoperative blood glucose values. Also, an elevated HbA1c level was independently associated with increased 30-day mortality (odds ratio 1.53 per percent increase [1.24-1.91]; P = 0.0005). This relationship persisted even after "borderline" diabetics were excluded. Furthermore, acute kidney injury was associated with elevated baseline HbA1c (P = 0.01). No association was found between HbA1c and postoperative infection risk (P = 0.48).
  
  
  CONCLUSIONS
  In non-diabetics, an elevated preoperative HbA1c level (>6.0%) is independently associated with significantly greater early mortality risk after elective cardiac surgery. Our findings suggest that HbA1c may have value as a screening tool to identify high-risk non-diabetic cardiac surgery patients.
authors.affiliation: Department of Anesthesiology, Duke University Medical Center, Durham, NC 27710, USA.
authors.forename: Christopher C C
authors.initials: CC
authors.lastname: Hudson
authors.forename: Ian J
authors.initials: IJ
authors.lastname: Welsby
authors.forename: Barbara
authors.initials: B
authors.lastname: Phillips-Bute
authors.forename: Joseph P
authors.initials: JP
authors.lastname: Mathew
authors.forename: Andrew
authors.initials: A
authors.lastname: Lutz
authors.forename: G
authors.initials: G
authors.lastname: Chad Hughes
authors.forename: Mark
authors.initials: M
authors.lastname: Stafford-Smith
mesh_terms: D000208:Acute Disease; D000368:Aged; D015415:Biomarkers / Q000378:metabolism; D001786:Blood Glucose / Q000378:metabolism; D006348:Cardiac Surgical Procedures / Q000009:adverse effects* / Q000401:mortality; D016208:Databases, Factual; D005260:Female; D005500:Follow-Up Studies; D006442:Glycated Hemoglobin / Q000378:metabolism*; D006801:Humans; D007239:Infections / Q000453:epidemiology / Q000209:etiology; D007668:Kidney / Q000293:injuries; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011183:Postoperative Complications / Q000453:epidemiology*; D012189:Retrospective Studies; D012307:Risk Factors
chemical_list: D015415:Biomarkers; D001786:Blood Glucose; D006442:Glycated Hemoglobin