A cohort study of digoxin exposure and mortality in men with prostate cancer
- To examine the association between digoxin exposure and mortality in men with prostate cancer using linked Irish National Cancer Registry and pharmacy claims data.
Patients and Methods
- Prostate cancer cases were identified from the database and digoxin exposure at prostate cancer diagnosis was identified from prescription claims.
- Digoxin users were matched to non-users using a propensity score to identify men with similar cardiovascular comorbidity.
- Adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated for the association between digoxin exposure and all-cause and prostate cancer-specific mortality (PCSM).
- Analyses were repeated in the propensity score-matched cohort.
- Effect modification of treatment with radiation or androgen-deprivation therapy by digoxin exposure was also assessed.
- In all, 5732 men with a prostate cancer diagnosis (2001–2006) were identified (digoxin exposed, 391). The median follow-up was 4.3 years.
- Digoxin exposure was associated with a small non-significant increase in PCSM in the full cohort (HR 1.13, 95% CI 0.91, 1.42) and the propensity. score-matched cohort (HR 1.17, 95% CI 0.88, 1.57).
- Adjusted HRs for all-cause mortality were increased for digoxin exposed men (HR 1.24, 95% CI 1.07, 1.43).
- Interactions with treatments received were not significant.
- These results suggest digoxin exposure is not associated with reduced PCSM.
- Further investigation of other cardiac glycosides that have shown anti-cancer potential may be warranted.