Shina Lee

A population-based approach indicates an overall higher patient mortality with peritoneal dialysis compared to hemodialysis in Korea

To date, only a few large-scale studies have measured the effect of dialysis modality on mortality in Asian populations. Here, we sought to compare survival between incident hemodialysis (HD) and peritoneal dialysis (PD) patients using the Korean Health Insurance Review & Assessment Service database. This enabled us to perform a population-based complete survey that included 32,280 incident dialysis patients and followed them for a median of 26.5 months. To reduce biases due to nonrandomization, we first matched 7049 patient pairs with similar propensity scores. Using the log-rank test, we found the mortality rate in PD patients was significantly higher than that in HD patients. Subsequent subgroup analyses indicated that in older patients (55 years and older), with the exception of the subgroup of patients with no comorbidities and the subgroup of patients with malignancy, PD was consistently associated with a higher mortality rate. In younger patients (under 55 years), regardless of the covariates, the survival rate of PD patients was comparable to that of HD patients. Thus, while the overall mortality rate was higher in incident PD patients, mortality rates of some incident PD and HD patients were comparable in Korea.

Risk of major cardiovascular events among incident dialysis patients: A Korean national population-based study.

BACKGROUND Dialysis patients are at high risk for cardiovascular diseases, but until now there have been no detailed analyses of the incidences among Asian patients initiating dialysis. The aims of this study were to determine the incidence rates of major adverse cardiac and cerebrovascular events (MACCE) and to compare them between incident HD patients and PD patients. METHODS We included all patients who had started dialysis between January 1, 2005 and December 31, 2008 in Korea, and analyzed 30,279 eligible patients [22,892 hemodialysis (HD) patients and 7387 peritoneal dialysis (PD) patients] by intention-to-treat. Median follow-up was 21.5 months. RESULTS The crude incidence rates were as follows: MACCE, 182 per 1000 patient-years (PY); major adverse cardiac events (MACE), 138/1000 PY; all-cause mortality, 116/1000 PY; non-fatal acute myocardial infarction (AMI), 18/1000 PY; target vessel revascularization (TVR), 17/1000 PY; and non-fatal stroke, 60/1000 PY. When comparing all baseline covariate-adjusted relative risks between HD and PD patients, HD is overall superior to PD in terms of MACCE. Further examined by each endpoint, all-cause mortality, non-fatal AMI, and TVR occurred significantly more frequently in patients on PD than in those on HD, whereas non-fatal hemorrhagic stroke occurred significantly more frequently in patients on HD than in those on PD. CONCLUSIONS The incidence of MACCE may be different from Western dialysis patients. HD is overall superior to PD in terms of MACCE as an initial dialysis modality. Underlying mechanisms differentially affecting cardiovascular outcomes by dialysis modality remain to be further elucidated.

An Assessment of Survival among Korean Elderly Patients Initiating Dialysis: A National Population-Based Study

Background Although the proportion of the elderly patients with incident end-stage renal disease (ESRD) patients has been increasing in Korea, there has been a lack of information on outcomes of dialysis treatment. This study aimed to assess the survival rate and to elucidate predictors for all-cause mortality among elderly Korean patients initiating dialysis. Methods We analyzed 11,301 patients (6,138 men) aged 65 years or older who had initiated dialysis from 2005 to 2008 and had followed up (median, 37.8 months; range, 3–84 months). Baseline demographics, comorbidities and mortality data were obtained using the database from the Health Insurance Review & Assessment Service. Results The unadjusted 5-year survival rate was 37.6% for all elderly dialysis patients, and the rate decreased with increasing age categories; 45.9% (65∼69), 37.5% (70∼74), 28.4% (75∼79), 24.1% (80∼84), and 13.7% (≥85 years). The multivariate Cox proportional hazard model revealed that age, sex, dialysis modality, the type of insurance, and comorbidities such as diabetes mellitus, myocardial infarction, congestive heart failure, peripheral vascular disease, cerebrovascular disease, dementia, chronic pulmonary disease, hemiparesis, liver disease, and any malignancy were independent predictors for mortality. In addition, survival rate was significantly higher in patients on hemodialysis compared to patients on peritoneal dialysis during the whole follow-up period in the intention-to-treat analysis. Conclusions Survival rate was significantly associated with age, sex, and various comorbidities in Korean elderly patients initiating dialysis. The results of our study can help to provide relevant guidance on the individualization strategy in elderly ESRD patients requiring dialysis.

Selective tubular activation of hypoxia-inducible factor-2α has dual effects on renal fibrosis

Hypoxia-inducible factor (HIF) is a key transcriptional factor in the response to hypoxia. Although the effect of HIF activation in chronic kidney disease (CKD) has been widely evaluated, the results have been inconsistent until now. This study aimed to investigate the effects of HIF-2α activation on renal fibrosis according to the activation timing in inducible tubule-specific transgenic mice with non-diabetic CKD. HIF-2α activation in renal tubular cells upregulated mRNA and protein expressions of fibronectin and type 1 collagen associated with the activation of p38 mitogen-activated protein kinase. In CKD mice, activation of HIF-2α at the beginning of CKD significantly aggravated renal fibrosis, whereas it did not lead to renal dysfunction. However, activation at a late-stage of CKD abrogated both renal dysfunction and fibrosis, which was associated with restoration of renal vasculature and amelioration of hypoxia through increased renal tubular expression of VEGF and its isoforms. As with tubular cells with HIF-2α activation, those under hypoxia also upregulated VEGF, fibronectin, and type 1 collagen expressions associated with HIF-1α activation. In conclusion, late-stage renal tubular HIF-2α activation has protective effects on renal fibrosis and the resultant renal dysfunction, thus it could represent a therapeutic target in late stage of CKD.

Technique failure in Korean incident peritoneal dialysis patients: a national population-based study

Background Technique failure is an important issue for peritoneal dialysis (PD) patients. In this study, we aimed to analyze technique failure rate in detail and to determine the predictors for technique failure in Korea. Methods We identified all patients who had started dialysis between January 1, 2005, and December 31, 2008, in Korea, using the Korean Health Insurance Review and Assessment Service database. A total of 7,614 PD patients were included, and the median follow-up was 24.9 months. Results The crude incidence rates of technique failure in PD patients were 54.1 per 1,000 patient-years. The cumulative 1-, 2-, and 3-year technique failure rates of PD patients were 4.9%, 10.3%, and 15.6%, respectively. However, those technique failure rates by Kaplan–Meier analysis were overestimated compared with the values by competing risks analysis, and the differences increased with the follow-up period. In multivariate analyses, diabetes mellitus and Medical Aid as a crude reflection of low socioeconomic status were independent risk factors in both the Cox proportional hazard model and Fine and Gray subdistribution model. In addition, cancer was independently associated with a lower risk of technique failure in the Fine and Gray model. Conclusion Technique failure was a major concern in patients initiating PD in Korea, especially in diabetic patients and Medical Aid beneficiaries. The results of our study offer a basis for risk stratification for technique failure.

Treatment and clinical outcomes of elderly idiopathic membranous nephropathy: A multicenter cohort study in Korea

Idiopathic membranous nephropathy (MN) is the most common glomerulonephritis in elderly patients showing nephrotic syndrome. However, little is known about its treatment options and outcomes in elderly MN patients at long term follow-up. We retrospectively enrolled patients with biopsy-proven MN between April 1990 and December 2015 from eight tertiary hospitals in Korea. Among them, we excluded patients who had secondary causes of MN and subnephrotic-range proteinuria. We evaluated the presenting features and clinical outcomes and analyzed the all-cause mortality, renal outcomes, infection, and remission with respect to age. During the median follow-up at 77.2 months, 198 younger patients (<65 years) and 133 elderly patients (≥65 years) were enrolled. Age was an independent risk factor for all-cause mortality, renal outcome, and infection (for all P < 0.05) except remission. In elderly patients, there was no significant factor associated with mortality rate. The use of angiotensin-converting enzyme inhibitor (ACEI) or angiotensin II receptor blocker (ARB) was significantly associated with renal outcome and infection (renal outcome, hazard ration [HR] 0.06, 95% confidence intervals [CI] 0.01-0.36, P = 0.003; infection, HR 0.20, 95% CI 0.04-0.94, P = 0.041). Immunosuppressant therapy significantly increased renal outcome (P = 0.045) and infection (P = 0.029) compared with conservative therapy. In conclusion, old age is one of the clinically important predictors for MN patients. Among the treatment of elderly MN patients, only ACEI or ARB was associated with beneficial effects on renal outcome and infection. Elderly MN patients need a more tailored regimen considering their comorbidities and condition.