Kidney transplantation waiting times and risk of cardiovascular events and mortality: a retrospective observational cohort study in Taiwan

OBJECTIVES: Patients with end-stage renal disease (ESRD) are at a high risk of cardiovascular events (CVEs), and kidney transplantation (KT) has been reported to improve risk of CVEs and survival. As the association of KT timing on long-term survival and clinical outcomes remains unclear, we investigated the association of different KT waiting times with clinical outcomes. DESIGN: Retrospective observational cohort study. SETTING: We conducted an observational cohort study using data from the National Health Insurance Research Database in Taiwan. Adult patients who initiated KT therapy from 1997 to 2013 were included. PARTICIPANTS: A total of 3562 adult patients who initiated uncomplicated KT therapy were included and categorised into four groups according to KT waiting times after ESRD: group 1 (<1 year), group 2 (1–3 years), group 3 (3–6 years) and group 4 (>6 years). PRIMARY OUTCOME MEASURES: The main outcomes were composite of all-cause death, non-fatal myocardial infarction or non-fatal stroke, based on the primary diagnosis in medical records during hospitalisation. RESULTS: Compared with group 1, the adjusted risk of primary outcome events (all-cause death, non-fatal myocardial infarction or non-fatal stroke) increased by 1.67 times in group 2 (95% CI: 1.40 to 2.00; p<0.001), 2.17 times in group 3 (95% CI: 1.73 to 2.71; p<0.001) and 3.10 times in group 4 (95% CI: 2.21 to 4.35; p<0.001). The rates of primary outcome events were 6.7%, 13.4% and 14.0% within 5 years, increasing to 19.5%, 26.3% and 30.8% within 10 years in groups 1, 2 and 3, respectively. CONCLUSIONS: Our results demonstrate that early KT is associated with superior long-term cardiovascular outcomes compared with late KT in selected patients with ESRD receiving uncomplicated KT, suggesting that an early KT could be a better treatment option for patients with ESRD who are eligible for transplantation.