Hypoalbuminemia Is Associated with Septic Revisions after Primary Surgery and Postoperative Infection after Revision Surgery

Study Design.Retrospective database review.Objective.To determine (1) the relationship between hypoalbuminemia and body mass index (BMI); (2) the association between malnutrition and revision spine surgery for septic reasons; and (3) the association between malnutrition and infection after aseptic revision spine surgery.Summary of Background Data.Although malnutrition has been suggested to increase the risk of infection after spine surgery, evidence supporting this hypothesis is conflicting.Methods.Patients undergoing revision spine surgery were identified in the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) from 2006 to 2014. Hypoalbuminemia (albumin<3.5g/dL) was used as a surrogate marker of malnutrition. Multivariate analysis was used to assess the association of hypoalbuminemia with septic versus aseptic revision spine surgery. The association between hypoalbuminemia and deep infection postoperatively within 30 days of aseptic revision surgeries was also assessed.Results.A total of 3136 patients who underwent revision spine surgery were identified; 2922 (93.2%) underwent surgery for aseptic reasons, and 214 (6.8%) for septic reasons. Hypoalbuminemia was present in all BMI groups including obese patients, though it was highest in underweight patients (22.4%). Patients who underwent surgery for septic reasons had a higher rate of hypoalbuminemia than those undergoing surgery for aseptic reasons (49.1% vs. 8.5%, P<0.001) with nine times the odds of having hypoalbuminemia (adjusted odds ratio, OR=9.17, P<0.001). Of the 2922 patients undergoing revision spine surgery for aseptic reasons, hypoalbuminemia was independently associated with acute deep infection within 30 days of surgery (adjusted OR=2.85, P=0.019).Conclusion.Malnutrition is more common in revision spine surgery for septic reasons when compared with aseptic revision surgery. Acute postoperative infection following aseptic revision surgery is also more common in patients with malnutrition. Further study, in the form of prospective trials, will help to increase our understanding of the effects of malnutrition in spine surgery.Level of Evidence.