title: Pre-operative labs: Wasted dollars or predictors of post-operative cardiac and septic events in orthopaedic trauma patients?
abstract: OBJECTIVE
  As US healthcare expenditures continue to rise, there is significant pressure to reduce the cost of inpatient medical services. Studies have estimated that over 70% of routine labs may not yield clinical benefits while adding over $300 in costs per day for every inpatient. Although orthopaedic trauma patients tend to have longer inpatient stays and hip fractures have been associated with significant morbidity, there is a dearth of data examining pre-operative labs in predicting post-operative adverse events in these populations. The purpose of this study was to assess whether pre-operative labs significantly predict post-operative cardiac and septic complications in orthopaedic trauma and hip fracture patients.
  
  
  METHODS
  Between 2006 and 2013, 56,336 (15.6%) orthopaedic trauma patients were identified and 27,441 patients (7.6%) were diagnosed with hip fractures. Pre-operative labs included sodium, BUN, creatinine, albumin, bilirubin, SGOT, alkaline phosphatase, white count, hematocrit, platelet count, prothrombin time, INR, and partial thromboplastin time. For each of these labs, patients were deemed to have normal or abnormal values. Patients were noted to have developed cardiac or septic complications if they sustained (1) myocardial infarction (MI), (2) cardiac arrest, or (3) septic shock within 30 days after surgery. Separate regressions incorporating over 40 patient characteristics including age, gender, pre-operative comorbidities, and labs were performed for orthopaedic trauma patients in order to determine whether pre-operative labs predicted adverse cardiac or septic outcomes.
  
  
  RESULTS
  749 (1.3%) orthopaedic trauma patients developed cardiac complications and 311 (0.6%) developed septic shock. Multivariate regression demonstrated that abnormal pre-operative platelet values were significantly predictive of post-operative cardiac arrest (OR: 11.107, p=0.036), and abnormal bilirubin levels were predictive (OR: 8.487, p=0.008) of the development of septic shock in trauma patients. In the hip fracture cohort, abnormal partial thromboplastin time was significantly associated with post-operative myocardial infarction (OR: 15.083, p=0.046), and abnormal bilirubin (OR: 58.674, p=0.002) significantly predicted the onset of septic shock.
  
  
  CONCLUSIONS
  This is the first study to demonstrate the utility of pre-operative labs in predicting perioperative cardiac and septic adverse events in orthopaedic trauma and hip fracture patients. Particular attention should be paid to haematologic/coagulation labs (platelets, PTT) and bilirubin values.
  
  
  METHODS
  Prognostic Level II.
authors.affiliation: The Vanderbilt Orthopaedic Institute Center for Health Policy, 1215 21st Avenue South, Suite 4200, Medical Center East, South Tower, Nashville, TN 37232, United States.
authors.forename: Nikita
authors.initials: N
authors.lastname: Lakomkin
authors.affiliation: The Vanderbilt Orthopaedic Institute Center for Health Policy, 1215 21st Avenue South, Suite 4200, Medical Center East, South Tower, Nashville, TN 37232, United States.
authors.forename: Vasanth
authors.initials: V
authors.lastname: Sathiyakumar
authors.affiliation: The Vanderbilt Orthopaedic Institute Center for Health Policy, 1215 21st Avenue South, Suite 4200, Medical Center East, South Tower, Nashville, TN 37232, United States.
authors.forename: Ashley C
authors.initials: AC
authors.lastname: Dodd
authors.affiliation: The Vanderbilt Orthopaedic Institute Center for Health Policy, 1215 21st Avenue South, Suite 4200, Medical Center East, South Tower, Nashville, TN 37232, United States.
authors.forename: A Alex
authors.initials: AA
authors.lastname: Jahangir
authors.affiliation: University of Wisconsin Hospital and Clinics, 1685 Highland Ave, Madison, WI 53704, United States.
authors.forename: Paul S
authors.initials: PS
authors.lastname: Whiting
authors.affiliation: The Vanderbilt Orthopaedic Institute Center for Health Policy, 1215 21st Avenue South, Suite 4200, Medical Center East, South Tower, Nashville, TN 37232, United States.
authors.forename: William T
authors.initials: WT
authors.lastname: Obremskey
authors.affiliation: The Vanderbilt Orthopaedic Institute Center for Health Policy, 1215 21st Avenue South, Suite 4200, Medical Center East, South Tower, Nashville, TN 37232, United States. Electronic address: manish.sethi@vanderbilt.edu.
authors.forename: Manish K
authors.initials: MK
authors.lastname: Sethi
mesh_terms: D000368:Aged; D001663:Bilirubin / Q000378:metabolism; D003362:Cost-Benefit Analysis; D003955:Diagnostic Tests, Routine / Q000191:economics / Q000706:statistics & numerical data*; D005260:Female; D050723:Fractures, Bone / Q000097:blood / Q000150:complications*; D006801:Humans; D008297:Male; D009104:Multiple Trauma / Q000097:blood / Q000150:complications*; D009203:Myocardial Infarction / Q000097:blood / Q000517:prevention & control; D019637:Orthopedic Procedures / Q000009:adverse effects*; D009985:Orthopedics / Q000191:economics*; D010976:Platelet Count / Q000379:methods; D011183:Postoperative Complications / Q000097:blood* / Q000517:prevention & control; D011237:Predictive Value of Tests; D057234:Preoperative Period; D011379:Prognosis; D012772:Shock, Septic / Q000097:blood / Q000517:prevention & control; D013530:Surgical Wound Infection / Q000097:blood / Q000517:prevention & control; D013925:Thromboplastin / Q000378:metabolism; D014481:United States; D019564:Unnecessary Procedures / Q000191:economics
chemical_list: D013925:Thromboplastin; D001663:Bilirubin
keywords: Bilirubin levels; Cardiac arrest; Hip fractures; Myocardial infarction; Orthopaedic trauma; Platelet count; Pre-operative labs; Septic shock; Thromboplastin time