Superior outcomes of kidney transplantation compared with dialysis: An optimal matched analysis of a national population-based cohort study between 2005 and 2008 in Korea

Abstract

Data regarding kidney transplantation (KT) and dialysis outcomes are rare in Asian populations. In the present study, we evaluated the clinical outcomes associated with KT using claims data from the Korean national public health insurance program. Among the 35,418 adult patients with incident dialysis treated between 2005 and 2008 in Korea, 1539 underwent KT. An optimal balanced risk set matching was attempted to compare the transplant group with the control group in terms of the overall survival and major adverse cardiac event-free survival. Before matching, the dialysis group was older and had more comorbidities. After matching, there were no differences in age, sex, dialysis modalities, or comorbidities. Patient survival was significantly better in the transplant group than in the matched control group (P < 0.001). In addition, the transplant group showed better major adverse cardiac event-free survival than the dialysis group (P < 0.001; hazard ratio, 0.49; 95% confidence interval, 0.32-0.75). Korean patients with incident dialysis who underwent long-term dialysis had significantly more cardiovascular events and higher all-cause mortality rates than those who underwent KT. Thus, KT should be more actively recommended in Korean populations.

Figure 1

Study flowchart. HD = hemodialysis, HIRA = Korea Health Insurance Review and Assessment Service, KT = kidney transplantation, PD = peritoneal dialysis.

Figure 2

Comparison of cumulative survival rate in the control group and transplant group for overall survival rate (A) and major adverse cardiac events (MACE) (B) after optimal balanced risk set matching. (A) Kaplan–Meier curves for the matched population including those in the control group (solid line) versus transplantation group (dashed line); (B) Kaplan–Meier curves for MACE in the matched population (solid line) versus transplantation group (dashed line). MACE: incidence of nonfatal myocardial infarction, hemorrhagic and ischemic stroke, coronary artery bypass graft surgery, or percutaneous coronary intervention.

Figure 3

Comparison of adjusted hazard ratios (HRs) for subgroups. (A) Adjusted HR of each subgroup for all-cause mortality; (B) adjusted HR of each subgroup for major adverse cardiac events (MACE). The adjusted covariates included age, sex, dialysis modality, health security system (HSS), and comorbidities (diabetes mellitus, myocardial infarction, congestive heart failure, peripheral vascular disease, cerebrovascular disease, chronic obstructive pulmonary disease, peptic ulcer disease, liver disease, and any type of cancer) for each subgroup (excluding own). (∗) The adjusted covariates included age, sex, dialysis modality, HSS, and Charlson comorbidity score for each subgroup. MACE: incidence of nonfatal myocardial infarction, hemorrhagic and ischemic stroke, coronary artery bypass graft surgery, or percutaneous coronary intervention. CI = confidence interval, COPD = chronic obstructive pulmonary disease, HR = hazard ratio, ITT = intention to treat.