title: Risk and patterns of secondary complications in surgical inpatients.
abstract: OBJECTIVE
  Little empirical evidence exists on how a first (index) complication influences the risk of specific subsequent secondary complications. Understanding these risks is important to elucidate clinical pathways of failure to rescue or death after postoperative complication.
  
  
  OBJECTIVE
  To understand patterns of secondary complications in the American College of Surgeons National Surgical Quality Improvement Program (NSQIP).
  
  
  METHODS
  Matched analysis using a cohort of 890 604 patients undergoing elective inpatient surgery from January 1, 2005, through December 31, 2011, identified in the NSQIP Participant Use Data File. Five index complications were studied: pneumonia, acute myocardial infarction, deep space surgical site infection, bleeding or transfusion event, and acute renal failure. Each patient with an index complication was matched to a control patient based on propensity for the index event and the number of event-free days. Outcomes were compared using conditional logistic regression.
  
  
  METHODS
  Rates of 30-day secondary complications and 30-day mortality.
  
  
  RESULTS
  Five cohorts were developed, each with 1:1 matching to controls, which were well balanced. Index pneumonia (n = 7947) was associated with increased odds of 30-day reintubation (odds ratio [OR], 17.1; 95% CI, 13.8-21.3; P < .001), ventilatory failure (OR, 15.9; 95% CI, 12.8-19.8; P < .001), sepsis (OR, 7.3; 95% CI, 6.2-8.6; P < .001), and shock (OR, 13.0; 95% CI, 10.4-16.2; P < .001). Index acute myocardial infarction was associated with increased rates of secondary bleeding or transfusion events (OR, 4.3; 95% CI, 3.3-5.8; P < .001), pneumonia (OR, 5.1; 95% CI, 2.6-10.2; P < .001), cardiac arrest (OR, 12.0; 95% CI, 7.5-19.2; P < .001), and reintubation (OR, 11.7; 95% CI, 8.4-16.3; P < .001). Deep space surgical site infection was associated with dehiscence (OR, 30.4; 95% CI, 19.9-46.5; P < .001), sepsis (OR, 13.1; 95% CI, 10.2-16.7; P < .001), shock (OR, 10.6; 95% CI, 6.4-17.7; P < .001), kidney injury (OR, 8.6; 95% CI, 3.9-18.8; P < .001), and acute renal failure (OR, 10.5; 95% CI, 3.8-29.3; P < .001). Index acute renal failure was associated with increased odds of cardiac arrest (OR, 25.3; 95% CI, 9.3-68.6; P < .001), reintubation (OR, 11.3; 95% CI, 7.4-17.1; P < .001), ventilatory failure (OR, 12.4; 95% CI, 8.2-18.8; P < .001), bleeding or transfusion events (OR, 11.3; 95% CI, 6.3-20.5; P < .001), and shock (OR, 11.2; 95% CI, 7.2-17.3; P < .001).
  
  
  CONCLUSIONS
  This investigation quantified the effect of index complications on patient risk of specific secondary complications. The defined pathways merit investigation as unique targets for quality improvement and benchmarking.
authors.affiliation: Center for Surgery and Public Health, Department of Surgery, Brigham and Women's Hospital, Boston, Massachusetts2Department of Surgery, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Elliot
authors.initials: E
authors.lastname: Wakeam
authors.affiliation: Center for Surgery and Public Health, Department of Surgery, Brigham and Women's Hospital, Boston, Massachusetts3Division of Respiratory and Critical Care Medicine, Department of Anesthesiology, Mayo Clinic, Rochester, Minnesota.
authors.forename: Joseph A
authors.initials: JA
authors.lastname: Hyder
authors.affiliation: Center for Surgery and Public Health, Department of Surgery, Brigham and Women's Hospital, Boston, Massachusetts.
authors.forename: Wei
authors.initials: W
authors.lastname: Jiang
authors.affiliation: Center for Surgery and Public Health, Department of Surgery, Brigham and Women's Hospital, Boston, Massachusetts.
authors.forename: Stuart A
authors.initials: SA
authors.lastname: Lipsitz
authors.affiliation: Center for Surgery and Public Health, Department of Surgery, Brigham and Women's Hospital, Boston, Massachusetts4Department of Surgery, University of Utah School of Medicine, Salt Lake City.
authors.forename: Sam
authors.initials: S
authors.lastname: Finlayson
mesh_terms: D058186:Acute Kidney Injury / Q000453:epidemiology / Q000209:etiology / Q000503:physiopathology; D000328:Adult; D000367:Age Factors; D000368:Aged; D016022:Case-Control Studies; D016001:Confidence Intervals; D017558:Elective Surgical Procedures / Q000009:adverse effects* / Q000379:methods; D005260:Female; D006801:Humans; D015994:Incidence; D007297:Inpatients / Q000706:statistics & numerical data*; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009203:Myocardial Infarction / Q000453:epidemiology / Q000209:etiology / Q000503:physiopathology; D016017:Odds Ratio; D011014:Pneumonia / Q000453:epidemiology / Q000209:etiology / Q000503:physiopathology; D011183:Postoperative Complications / Q000175:diagnosis* / Q000453:epidemiology* / Q000628:therapy; D019106:Postoperative Hemorrhage / Q000453:epidemiology / Q000209:etiology / Q000503:physiopathology; D012189:Retrospective Studies; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D012737:Sex Factors; D013530:Surgical Wound Infection / Q000453:epidemiology / Q000209:etiology / Q000503:physiopathology; D015996:Survival Rate