title: A procalcitonin-based algorithm to guide antibiotic therapy in secondary peritonitis following emergency surgery: a prospective study with propensity score matching analysis.
abstract: BACKGROUND
  Procalcitonin (PCT)-based algorithms have been used to guide antibiotic therapy in several clinical settings. However, evidence supporting PCT-based algorithms for secondary peritonitis after emergency surgery is scanty. In this study, we aimed to investigate whether a PCT-based algorithm could safely reduce antibiotic exposure in this population.
  
  
  RESULTS
  From April 2012 to March 2013, patients that had secondary peritonitis diagnosed at the emergency department and underwent emergency surgery were screened for eligibility. PCT levels were obtained pre-operatively, on post-operative days 1, 3, 5, and 7, and on subsequent days if needed. Antibiotics were discontinued if PCT was <1.0 ng/mL or decreased by 80% versus day 1, with resolution of clinical signs. Primary endpoints were time to discontinuation of intravenous antibiotics for the first episode and adverse events. Historical controls were retrieved for propensity score matching. After matching, 30 patients in the PCT group and 60 in the control were included for analysis. The median duration of antibiotic exposure in PCT group was 3.4 days (interquartile range [IQR] 2.2 days), while 6.1 days (IQR 3.2 days) in control (p < 0.001). The PCT algorithm significantly improves time to antibiotic discontinuation (p < 0.001, log-rank test). The rates of adverse events were comparable between 2 groups. Multivariate-adjusted extended Cox model demonstrated that the PCT-based algorithm was significantly associated with a 87% reduction in hazard of antibiotic exposure within 7 days (hazard ratio [HR] 0.13, 95% CI 0.07-0.21, p < 0.001), and a 68% reduction in hazard after 7 days (adjusted HR 0.32, 95% CI 0.11-0.99, p  =  0.047). Advanced age, coexisting pulmonary diseases, and higher severity of illness were significantly associated with longer durations of antibiotic use.
  
  
  CONCLUSIONS
  The PCT-based algorithm safely reduces antibiotic exposure in this study. Further randomized trials are needed to confirm our findings and incorporate cost-effectiveness analysis.
  
  
  BACKGROUND
  Australian New Zealand Clinical Trials Registry ACTRN12612000601831.
authors.affiliation: The Graduate Institute of Clinical Medicine, National Taiwan University College of Medicine, Taipei, Taiwan; Division of General Surgery, Department of Surgery, Chang Gung Memorial Hospital, Keelung Branch, Keelung, Taiwan.
authors.forename: Ting-Shuo
authors.initials: TS
authors.lastname: Huang
authors.affiliation: Division of Infectious Diseases, Department of Medicine, Chang Gung Memorial Hospital, Keelung Branch, Keelung, Taiwan.
authors.forename: Shie-Shian
authors.initials: SS
authors.lastname: Huang
authors.affiliation: Institute of Biopharmaceutical Sciences, National Yang-Ming University, Taipei, Taiwan; Department of Education and Research, Taipei City Hospital, Taipei, Taiwan.
authors.forename: Yu-Chiau
authors.initials: YC
authors.lastname: Shyu
authors.affiliation: Division of General Surgery, Department of Surgery, Chang Gung Memorial Hospital, Keelung Branch, Keelung, Taiwan.
authors.forename: Chun-Hui
authors.initials: CH
authors.lastname: Lee
authors.affiliation: Division of General Surgery, Department of Surgery, Chang Gung Memorial Hospital, Keelung Branch, Keelung, Taiwan.
authors.forename: Shyh-Chuan
authors.initials: SC
authors.lastname: Jwo
authors.affiliation: The Graduate Institute of Clinical Medicine, National Taiwan University College of Medicine, Taipei, Taiwan.
authors.forename: Pei-Jer
authors.initials: PJ
authors.lastname: Chen
authors.affiliation: Division of General Surgery, Department of Surgery, Chang Gung Memorial Hospital, Keelung Branch, Keelung, Taiwan.
authors.forename: Huang-Yang
authors.initials: HY
authors.lastname: Chen
mesh_terms: D000368:Aged; D000465:Algorithms; D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D002116:Calcitonin / Q000097:blood*; D015740:Calcitonin Gene-Related Peptide; D004636:Emergency Service, Hospital; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D010538:Peritonitis / Q000097:blood* / Q000150:complications / Q000188:drug therapy* / Q000601:surgery; D016016:Proportional Hazards Models; D011446:Prospective Studies; D011498:Protein Precursors / Q000097:blood*
chemical_list: D000900:Anti-Bacterial Agents; C000606589:CALCA protein, human; D011498:Protein Precursors; D002116:Calcitonin; D015740:Calcitonin Gene-Related Peptide