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 on 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
kidney transplantation therapy from 1997 to 2013 were included.
Participants: A total of 3562 adult patients who initiated uncomplicated
KT therapy were included and categorized 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
measure: The main outcome was a composite of all-cause death, nonfatal
myocardial infarction, or nonfatal stroke, based on the primary diagnosis
in medical records during hospitalization. Results: Compared with Group 1,
the adjusted risk of primary outcome events (all-cause death, nonfatal
myocardial infarction, or nonfatal stroke) increased by 1.67 times in
Group 2 (95% CI: 1.40–2.00; P <0.001), 2.17 times in Group 3 (95%
CI: 1.73–2.71; P <0.001), and 3.10 times in Group 4 (95% CI:
2.21–4.35; P <0.001). The rates of primary outcome events were
6.7%, 13.4%, and 14.0% within five 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 to late KT in selected ESRD
patients receiving uncomplicated KT, suggesting that an early KT could be
a better treatment option for ESRD patients who are eligible for
transplantation.