title: Surgical duration and risk of Urinary Tract Infection: An analysis of 1,452,369 patients using the National Surgical Quality Improvement Program (NSQIP).
abstract: BACKGROUND
  While the relationship between surgical duration and post-operative morbidity has been well-studied in specific procedures for specific complications, there is a paucity of literature that addresses whether longer surgeries increase the risk of Urinary Tract Infection (UTI). We have performed the first study to elucidate the relationship between increasing surgical duration and UTI events across surgical specialties via the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database.
  
  
  METHODS
  Patients, who received general anesthesia, were stratified into quintiles by a calculated z-score for their anesthesia time based on the standard deviation and mean of their respective current procedural terminology (CPT) code. Z-score analysis standardized interprocedural differences in anesthesia time. Multivariate regression analysis was employed to evaluate the independent association of anesthesia time with risk of UTI. Multiple sub-analyses were performed to evaluate the robustness of our results.
  
  
  RESULTS
  22,305 patients (1.5%) experienced a UTI. Compared to the mean procedural duration as represented by the 3rd quintile, procedures of longer duration were independently associated with increased risk of UTI (OR, 1.156 (95% CI 1.104-1.21); OR, 1.758 (95% CI 1.682-1.838)) while procedures of shorter duration were associated with reduced risk (OR, .928 (95% CI .873-.987); OR, .955 (95% CI .906-1.007)).
  
  
  CONCLUSIONS
  Our findings suggest that increasing surgical duration may independently worsen the risk of post-operative UTI pan-surgically. We hope that our results will help guide decision making regarding the safety of combination procedures as well as improve pre-operative risk stratification.
authors.affiliation: Department of Surgery, Northwestern University, Feinberg School of Medicine, Chicago, IL, USA. Electronic address: c-qin@northwestern.edu.
authors.forename: Charles
authors.initials: C
authors.lastname: Qin
authors.affiliation: Department of Anesthesiology, Northwestern University, Feinberg School of Medicine, Chicago, IL, USA. Electronic address: g-jr@northwestern.edu.
authors.forename: Gildasio
authors.initials: G
authors.lastname: de Oliveira
authors.affiliation: Department of Surgery, Northwestern University, Feinberg School of Medicine, Chicago, IL, USA. Electronic address: nicholas.hackett@northwestern.edu.
authors.forename: Nicholas
authors.initials: N
authors.lastname: Hackett
authors.affiliation: Department of Surgery, Northwestern University, Feinberg School of Medicine, Chicago, IL, USA. Electronic address: jokim@nmh.org.
authors.forename: John Y S
authors.initials: JY
authors.lastname: Kim
mesh_terms: D000328:Adult; D000368:Aged; D000768:Anesthesia, General; D016208:Databases, Factual; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009017:Morbidity; D015999:Multivariate Analysis; D061646:Operative Time; D011183:Postoperative Complications / Q000209:etiology*; D058996:Quality Improvement / Q000706:statistics & numerical data*; D012307:Risk Factors; D013997:Time Factors; D014552:Urinary Tract Infections / Q000453:epidemiology / Q000209:etiology*
keywords: 30-Day outcomes; Anesthesia time; NSQIP; Post-operative UTI; Surgical duration