title: Temporal trends in the epidemiology of severe postoperative sepsis after elective surgery: a large, nationwide sample.
abstract: BACKGROUND
  Multiple studies have used administrative datasets to examine the epidemiology of sepsis in general, but the entity of postoperative sepsis has been studied less intensively. Therefore, we undertook an analysis of the epidemiology of postoperative sepsis using the Nationwide Inpatient Sample, the largest in-patient dataset available in the United States.
  
  
  METHODS
  Elective admissions of patients aged 18 yr or older with a length of stay more than 3 days for any 1 of the 20 most common elective operative procedures were extracted from the dataset for the years 1997-2006. Postoperative sepsis was defined using the appropriate International Classification of Diseases, Ninth Revision, Clinical Modification codes; severe sepsis was defined as sepsis along with organ dysfunction. Logistic regression was used to assess the significance of temporal trends after adjusting for relevant demographic characteristics, operative procedure, and comorbid conditions.
  
  
  RESULTS
  We identified 2,039,776 admissions for analysis. The rate of severe sepsis increased from 0.3% in 1997 to 0.9% in 2006. This trend persisted after adjusting for relevant covariables-the adjusted odds ratio of severe sepsis per year increase in the study period was 1.12 (95% CI, 1.11-1.13; P < 0.001). The in-hospital mortality rate for patients with severe postoperative sepsis declined from 44.4% in 1997 to 34.0% in 2006; this trend also persisted after adjustment for relevant covariables-the adjusted odds ratio per year was 0.94 (95% CI, 0.93-0.95; P < 0.001).
  
  
  CONCLUSIONS
  During the 10-yr period that we studied, there was a marked increase in the rate of severe postoperative sepsis but a concomitant decrease in the in-hospital mortality rate in severe sepsis.
authors.affiliation: Department of Anesthesia, Critical Care, and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114, USA
authors.forename: Brian T
authors.initials: BT
authors.lastname: Bateman
authors.forename: Ulrich
authors.initials: U
authors.lastname: Schmidt
authors.forename: Mitchell F
authors.initials: MF
authors.lastname: Berman
authors.forename: Edward A
authors.initials: EA
authors.lastname: Bittner
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D002908:Chronic Disease; D016208:Databases, Factual; D017558:Elective Surgical Procedures; D005006:Ethnicity; D005260:Female; D006276:Health Facility Size; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D016017:Odds Ratio; D011183:Postoperative Complications / Q000453:epidemiology*; D018805:Sepsis / Q000453:epidemiology*; D012737:Sex Factors; D014481:United States / Q000453:epidemiology; D055815:Young Adult