title: Venous thromboembolism and effect of comorbidity in bladder cancer: A danish nationwide cohort study of 13,809 patients diagnosed between 1995 and 2011.
abstract: Bladder cancer (BC) is associated with venous thromboembolism (VTE), but data on the effect of comorbidities are scarce.
  
  
  
  Population-based cohort study with 13,809 patients with BC diagnosed in Denmark (1995-2011) and a general population comparison cohort matched on age, sex, and comorbidities (n = 132,421). Risk of VTE, pulmonary embolism and deep venous thrombosis was computed for the first month, 3 months, 1 year, and 5 years following cancer diagnosis and stratified by Charlson Comorbidity Index (CCI) scores, cystectomy, and metastases.
  
  
  
  VTE risk was higher among the patients with BC than in the comparison cohort during five years of follow-up (risk difference = 20 per 1,000 persons [95% CI: 16-23]). Excess risk was relatively stable with increasing comorbidity score. In the first year, the risk difference was 17 per 1,000 persons (95% CI: 14-21) and 16 (95% CI: 4.8-27) for CCI score = 0 and CCI score = 4, respectively, and similar results were observed by stratification on pulmonary embolism and deep venous thrombosis. For patients with BC undergoing cystectomy, VTE risk was 70-fold higher than in the general population cohort within 3 months after diagnosis.
  
  
  
  BC is associated with increased risk of VTE, compared with the general Danish population. Risks are particularly high for VTE after cystectomy. Risk did not increase with higher comorbidity burden, as the relative risk of VTE was greatest among patients without comorbidity. Clinical attention to VTE risk, particularly cystectomy-related VTE, in patients with BC is appropriate irrespective of comorbidities.
authors.affiliation: Department of Clinical Epidemiology, Aarhus University Hospital, Aarhus, Denmark. Electronic address: ao@clin.au.dk.
authors.forename: Anne G
authors.initials: AG
authors.lastname: Ording
authors.affiliation: Department of Urology, University of North Carolina School of Medicine, Chapel Hill, NC; Department of Epidemiology, University of North Carolina School of Public Health, Chapel Hill, NC; Department of Health Policy and Management, University of North Carolina School of Public Health, Chapel Hill, NC.
authors.forename: Matthew E
authors.initials: ME
authors.lastname: Nielsen
authors.affiliation: Department of Urology, University of North Carolina School of Medicine, Chapel Hill, NC.
authors.forename: Angela B
authors.initials: AB
authors.lastname: Smith
authors.affiliation: Department of Clinical Epidemiology, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: Erzsébet
authors.initials: E
authors.lastname: Horváth-Puhó
authors.affiliation: Department of Clinical Epidemiology, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: Henrik T
authors.initials: HT
authors.lastname: Sørensen
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D015897:Comorbidity; D003718:Denmark; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D001749:Urinary Bladder Neoplasms / Q000150:complications*; D054556:Venous Thromboembolism / Q000150:complications*
keywords: Carcinoma; Comorbidity; Epidemiology; Urinary bladder neoplasms; Venous thromboembolism