title: Digoxin use after diagnosis of colorectal cancer and survival: a population-based cohort study.
abstract: BACKGROUND
  Digoxin has been shown to affect a number of pathways that are of relevance to cancer, and its use has been associated with increased risks of breast and uterus cancer and, more recently, a 40% increase in colorectal cancer risk. These findings raise questions about the safety of digoxin use in colorectal cancer patients, and, therefore, we investigated whether digoxin use after colorectal cancer diagnosis increased the risk of colorectal cancer-specific mortality.
  
  
  METHODS
  A cohort of 10,357 colorectal cancer patients newly diagnosed from 1998 to 2009 was identified from English cancer registries and linked to the UK Clinical Practice Research Datalink (to provide digoxin and other prescription records) and to the Office of National Statistics mortality data (to identify 2,724 colorectal cancer-specific deaths). Using time-dependent Cox regression models, unadjusted and adjusted HRs and 95% confidence intervals (CI) were calculated for the association between postdiagnostic exposure to digoxin and colorectal cancer-specific mortality.
  
  
  RESULTS
  Overall, 682 (6%) colorectal cancer patients used digoxin after diagnosis. Digoxin use was associated with a small increase in colorectal cancer-specific mortality before adjustment (HR, 1.25; 95% CI, 1.07-1.46), but after adjustment for confounders, the association was attenuated (adjusted HR, 1.10; 95% CI, 0.91-1.34) and there was no evidence of a dose response.
  
  
  CONCLUSIONS
  In this large population-based colorectal cancer cohort, there was little evidence of an increase in colorectal cancer-specific mortality with digoxin use after diagnosis.
  
  
  CONCLUSIONS
  These results provide some reassurance that digoxin use is safe in colorectal cancer patients.
authors.affiliation: Cancer Epidemiology and Health Services Research Group, Centre for Public Health, Queen's University Belfast, Belfast, Northern Ireland, United Kingdom.
authors.forename: Reema A
authors.initials: RA
authors.lastname: Karasneh
authors.affiliation: Cancer Epidemiology and Health Services Research Group, Centre for Public Health, Queen's University Belfast, Belfast, Northern Ireland, United Kingdom. Centre of Excellence for Public Health (NI), Queen's University Belfast, Belfast, Northern Ireland, United Kingdom.
authors.forename: Liam J
authors.initials: LJ
authors.lastname: Murray
authors.affiliation: School of Pharmacy, Queen's University Belfast, Belfast, Northern Ireland, United Kingdom.
authors.forename: Carmel M
authors.initials: CM
authors.lastname: Hughes
authors.affiliation: Cancer Epidemiology and Health Services Research Group, Centre for Public Health, Queen's University Belfast, Belfast, Northern Ireland, United Kingdom. c.cardwell@qub.ac.uk.
authors.forename: Chris R
authors.initials: CR
authors.lastname: Cardwell
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015179:Colorectal Neoplasms / Q000175:diagnosis / Q000401:mortality*; D004077:Digoxin / Q000009:adverse effects*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016019:Survival Analysis
chemical_list: D004077:Digoxin