title: Gram-negative bacteremia as a clinical marker of occult malignancy.
abstract: Gram-negative bacteremia may be a harbinger of occult cancer. We examined the risk of cancer following hospitalization with bacteremia.
  
  
  
  Using medical databases, we conducted a nationwide population-based cohort study of all Danes with a discharge diagnosis of Gram-negative bacteremia during 1994-2013. We calculated absolute risks and standardized incidence ratios (SIRs) of cancer, comparing the observed risk to that expected in the general population.
  
  
  
  We observed 1379 cancers vs. 988 expected among 11,753 patients with Gram-negative bacteremia, corresponding to an overall SIR of 1.40 (95% confidence interval (CI): 1.32-1.47). During the first 6 months following the bacteremia diagnosis, the SIR for cancer was 3.33-fold (95% CI: 2.99-3.69) increased, corresponding to an absolute risk of 3.05%. The increased risk stemmed mainly from higher than expected occurrence of gastrointestinal cancer (3- to 13-fold higher), genitourinary cancer (4- to 10-fold higher), non-Hodgkin lymphoma (5-fold higher), non-specified metastatic cancer (5-fold higher), and breast and lung cancer (2-fold higher). The 6-12 months SIR for any cancer was 1.46 (95% CI: 1.22-1.72), and beyond 1 year of follow-up, the SIR declined to 1.13 (95% CI: 1.05-1.20).
  
  
  
  Gram-negative bacteremia is a clinical marker of occult cancer.
authors.affiliation: Department of Clinical Epidemiology, Aarhus University Hospital, Olof Palmes Allé 43-45, 8200 Aarhus N, Denmark. Electronic address: kks@clin.au.dk.
authors.forename: Kirstine K
authors.initials: KK
authors.lastname: Søgaard
authors.affiliation: Department of Clinical Epidemiology, Aarhus University Hospital, Olof Palmes Allé 43-45, 8200 Aarhus N, Denmark.
authors.forename: Dóra K
authors.initials: DK
authors.lastname: Farkas
authors.affiliation: Department of Clinical Epidemiology, Aarhus University Hospital, Olof Palmes Allé 43-45, 8200 Aarhus N, Denmark.
authors.forename: Mette
authors.initials: M
authors.lastname: Søgaard
authors.affiliation: Department of Clinical Microbiology, Aalborg University Hospital, Mølleparkvej 10, 9000 Aalborg, Denmark; Department of Clinical Medicine, Aalborg University, Søndre Skovvej 15, 9000 Aalborg, Denmark.
authors.forename: Henrik C
authors.initials: HC
authors.lastname: Schønheyder
authors.affiliation: Department of Clinical Epidemiology, Aarhus University Hospital, Olof Palmes Allé 43-45, 8200 Aarhus N, Denmark.
authors.forename: Reimar W
authors.initials: RW
authors.lastname: Thomsen
authors.affiliation: Department of Clinical Epidemiology, Aarhus University Hospital, Olof Palmes Allé 43-45, 8200 Aarhus N, Denmark.
authors.forename: Henrik T
authors.initials: HT
authors.lastname: Sørensen
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D016470:Bacteremia / Q000150:complications* / Q000453:epidemiology / Q000382:microbiology; D015331:Cohort Studies; D003718:Denmark / Q000453:epidemiology; D005260:Female; D016905:Gram-Negative Bacterial Infections / Q000150:complications* / Q000453:epidemiology / Q000382:microbiology*; D006760:Hospitalization; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000150:complications* / Q000453:epidemiology; D018570:Risk Assessment; D012307:Risk Factors
keywords: Bacteremia; Neoplasm; Risk