Prostate Cancer, Kidney Transplant Wait Time, and Mortality in Maintenance Dialysis Patients: A Cohort Study Using Linked United States Renal Data System Data

RATIONALE & OBJECTIVE: The impact of prostate cancer on mortality in patients with end-stage kidney disease may be different from the general population. Prostate cancer may also delay the kidney transplant but has not been studied in a population-based cohort. We examined how prostate cancer influenced time to kidney transplant and death in a dialysis population. STUDY DESIGN: Retrospective population-based, risk-set propensity score–matched cohort study. SETTING & PARTICIPANTS: Men, 40-79 years old, who were dialysis-dependent Medicare beneficiaries without prior documented prostate cancer, from the United States Renal Data System. EXPOSURES: Incident prostate cancer, identified using International Classification of Disease, Ninth Revision, Clinical Modification system diagnosis code 185. OUTCOMES: Time to kidney transplant and death. ANALYTICAL APPROACH: Propensity-based risk-set matching to reduce bias between cases and controls. Cox proportional hazards model for time to death, and Fine-Gray competing risk model for time to kidney transplant. RESULTS: Among a total of 588,478 male dialysis patients who met the eligibility criteria, 18,162 had claims for prostate cancer. After propensity-based risk-set matching, 15,554 pairs of prostate cancer cases and controls were identified. Among the matched pairs, survival rates were 76%, 48%, and 30% at 1, 3, and 5 years in the prostate cancer group, compared with 80%, 51%, and 33% in the control group, with relative mortality of 95%, 94%, and 91% respectively (log-rank test P < 0.001). Prostate cancer was associated with a 22% lower likelihood of kidney transplant (HR: 0.78; 95% CI: 0.72-0.85) and 11% higher likelihood of death (HR: 1.11; 95% CI: 1.08-1.14) compared with controls. Kidney transplant was associated with a 4-fold improvement in overall survival, both in patients with and without prostate cancer (HR: 0.20; 95% CI: 0.18-0.21). LIMITATIONS: Retrospective registry study. CONCLUSIONS: Prostate cancer is associated with a modest increase in the risk of death and time to transplant in patients with end-stage kidney disease. Kidney transplant is associated with the same degree of survival benefit among those with pretransplant prostate cancer as those without.