title: The prognostic impact of comorbidities on renal cancer, 1995 to 2006: a Danish population based study.
abstract: OBJECTIVE
  Comorbid disease in patients with renal cancer may affect renal cancer prognosis. We estimated the risk of 1 and 5-year mortality in patients with renal cancer in northern Denmark by comorbidity status.
  
  
  METHODS
  We performed a cohort study tracking mortality in all patients with an incident diagnosis of renal cancer between 1995 and 2006 in a population of 1.6 million residents in northern Denmark. Using hospital discharge data before cancer diagnosis we calculated Charlson comorbidity index scores (0, 1-2 or 3+) in patients with renal cancer as well as absolute survival and relative mortality estimates according to comorbidity level.
  
  
  RESULTS
  We identified 2,315 patients with renal cancer, of whom 950 (41%) had comorbidity. The prevalence of comorbidity tended to increase during the study period with the rate in patients with a score of 3+ increasing from 9% to 13%. The 5-year relative mortality rate was lower in patients with a positive Charlson index score with mortality almost twice as high in those with a score of 3+ and 1.2-fold higher in those with a score of 1-2 compared to mortality in those with no comorbidity. Generally similar patterns were observed for 1-year relative mortality.
  
  
  CONCLUSIONS
  Comorbidity is common in patients with renal cancer and it is a negative prognostic factor.
authors.affiliation: Department of Urology, Viborg Hospital, Viborg, Denmark. Lars.Lund@vanderbilt.edu
authors.forename: Lars
authors.initials: L
authors.lastname: Lund
authors.forename: Jacob
authors.initials: J
authors.lastname: Jacobsen
authors.forename: Mette
authors.initials: M
authors.lastname: Nørgaard
authors.forename: Joseph K
authors.initials: JK
authors.lastname: McLaughlin
authors.forename: William J
authors.initials: WJ
authors.lastname: Blot
authors.forename: Michael
authors.initials: M
authors.lastname: Borre
authors.forename: Henrik T
authors.initials: HT
authors.lastname: Sørensen
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D002292:Carcinoma, Renal Cell / Q000453:epidemiology* / Q000473:pathology / Q000628:therapy; D002423:Cause of Death; D015331:Cohort Studies; D015897:Comorbidity; D016001:Confidence Intervals; D003718:Denmark / Q000453:epidemiology; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D007680:Kidney Neoplasms / Q000453:epidemiology* / Q000473:pathology / Q000628:therapy; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011379:Prognosis; D016016:Proportional Hazards Models; D012042:Registries; D012189:Retrospective Studies; D012720:Severity of Illness Index; D017678:Sex Distribution; D016019:Survival Analysis; D055815:Young Adult