Wu-Chang Yang

Incidence, prevalence and mortality trends of dialysis end-stage renal disease in Taiwan from 1990 to 2001: the impact of national health insurance

BACKGROUND Incident and prevalent (I&P) rates in dialysis end-stage renal disease (ESRD) patients in Taiwan increased rapidly following the launch of National Health Insurance (NHI) in 1995. Our aim was to explore the impact of NHI on the status and trends of ESRD epidemiology in Taiwan. METHODS This study was conducted using retrospective cohort analysis of data collected from the Taiwan national dialysis registry. RESULTS From 1990 to 2001, I&P rates of ESRD patients increased 2.6 times from 126 to 331 per million populations (pmp) and 3.46 times from 382 to 1322 pmp, respectively. Increasing ESRD was seen in patients who were middle-aged, elderly and who had diabetic nephropathy as their primary renal disease. The mean age of I&P patients increased by 7.2 years and 7.1 years, respectively. All of these parameters increased markedly in 1995, the year of NHI implementation. First-year mortality decreased to 7.8 per 1000 patient-months in 1994, and then increased to 18.0 in 2001. The cumulative survival rate of the elderly subgroup (age >65) in the incident 1990-1994 cohort was greater than in the 1995-1999 cohort. These data indicated that NHI implementation significantly influenced the inflow and the mortality of ESRD patients. CONCLUSION In addition to presenting ESRD epidemiology in Taiwan, this study demonstrated that NHI implementation stimulated the growth of treated ESRD populations. Preventive plans mounted against chronic kidney diseases will be essential to reduce the growth of ESRD patient numbers and consequent economic burdens.

Impact of the clinical conditions at dialysis initiation on mortality in incident haemodialysis patients: a national cohort study in Taiwan

BACKGROUND Glomerular filtration rate (GFR) and co-morbidity at dialysis initiation in relation to mortality in end-stage renal disease is still controversial. We studied factors potentially related to the mortality in incident haemodialysis (HD) patients. METHODS A national database included 23 551 incident HD patients from July 2001 to December 2004. Kaplan-Meier and Cox regression analyses were performed to assess the association between GFR estimated by the four-variable Modified Diet in Renal Disease equation and all-cause mortality. Analyses were performed from Day 91 after the start of dialysis. Patients were classified into five groups (quintiles) based on estimated glomerular filtration rate (eGFR) at the start of dialysis. RESULTS The median eGFR at dialysis initiation was low (4.7 mL/min/1.73 m(2)), as was the mortality in the first year of dialysis [13.2/100 patient-year, 95% confidence interval (95% CI) = 12.8-13.7]. There was an inverse association between lower eGFR and higher survival rate. The Cox regression model revealed an increase in mortality risk in Q5 (hazard ratio [HR] = 2.44, 95% CI = 2.11-2.81), Q4 (HR = 1.66, 95% CI = 1.43-1.93), Q3 (HR = 1.21, 95% CI = 1.04-1.41) and Q2 (HR = 1.18, 95% CI = 1.01-1.37) compared with the reference group of Q1 after adjusting for year of application, primary diseases (chronic glomerulonephritis, diabetic nephropathy, hypertension, chronic tubulointerstitial nephritis and others), demographics (age, sex), presence of co-morbidity (diabetes mellitus, hypertension, congestive heart failure, ischaemic heart diseases, cerebrovascular diseases, malignancies, liver cirrhosis, tuberculosis, other diseases and free of reported of co-morbidities) and haematocrit. Propensity score analysis also showed a higher eGFR to be associated with increased mortality risks. Adjustment for all covariates explained a high percentage of excess risk of mortality in the groups with low eGFR, but less risk in the groups with higher eGFR. CONCLUSIONS Lower eGFR at dialysis initiation is associated with lower mortality. Conditions at dialysis initiation explained excess 1-year mortality risk differently in patients who began dialysis at different levels of eGFR. Other factors likely contribute to the mortality of patients initiating dialysis at higher eGFR levels, and further study is needed.

Far-Infrared Therapy: A Novel Treatment to Improve Access Blood Flow and Unassisted Patency of Arteriovenous Fistula in Hemodialysis Patients

Vascular access malfunction, usually presenting with an inadequate access flow (Qa), is the leading cause of morbidity and hospitalization in hemodialysis (HD) patients. Many methods of thermal therapy have been tried for improving Qa but with limited effects. This randomized trial was designed to evaluate the effect of far-infrared (FIR) therapy on access flow and patency of the native arteriovenous fistula (AVF). A total of 145 HD patients were enrolled with 73 in the control group and 72 in the FIR group. A WS TY101 FIR emitter was used for 40 min, and hemodynamic parameters were measured by the Transonic HD(02) monitor during HD. The Qa(1)/Qa(2) and Qa(3)/Qa(4) were defined as the Qa measured at the beginning/at 40 min later in the HD session before the initiation and at the end of the study, respectively. The incremental change of Qa in the single HD session with FIR therapy was significantly higher than that without FIR therapy (13.2 +/- 114.7 versus -33.4 +/- 132.3 ml/min; P = 0.021). In comparison with control subjects, patients who received FIR therapy for 1 yr had (1) a lower incidence (12.5 versus 30.1%; P < 0.01) and relative incidence (one episode per 67.7 versus one episode per 26.7 patient-months; P = 0.03) of AVF malfunction; (2) higher values of the following parameters, including Delta(Qa(4) - Qa(3)) (36.2 +/- 82.4 versus -12.7 +/- 153.6 ml/min; P = 0.027), Delta(Qa(3) - Qa(1)) (36.3 +/- 166.2 versus -51.7 +/- 283.1 ml/min; P = 0.035), Delta(Qa(4) - Qa(2)) (99.2 +/- 144.4 versus -47.5 +/- 244.5 ml/min; P < 0.001), and Delta(Qa(4) - Qa(2)) - Delta(Qa(3) - Qa(1)) (62.9 +/- 111.6 versus 4.1 +/- 184.5 ml/min; P = 0.032); and (3) a better unassisted patency of AVF (85.9 versus 67.6%; P < 0.01). In conclusion, FIR therapy, a noninvasive and convenient therapeutic modality, can improve Qa and survival of the AVF in HD patients through both its thermal and its nonthermal effects.

Far Infrared Therapy Inhibits Vascular Endothelial Inflammation via the Induction of Heme Oxygenase-1

Objective—Survival of arteriovenous fistulas (AVFs) in hemodialysis patients is associated with both far infrared (FIR) therapy and length polymorphisms of the heme oxygenase-1 (HO-1) promoter. In this study, we evaluated whether there is an interaction between FIR radiation and HO-1 in regulating vascular inflammation. Methods and Results—Treatment of cultured human umbilical vein endothelial cells (ECs) with FIR radiation stimulated HO-1 protein, mRNA, and promoter activity. HO-1 induction was dependent on the activation of the antioxidant responsive element/NF-E2-related factor-2 complex, and was likely a consequence of heat stress. FIR radiation also inhibited tumor necrosis factor (TNF)-&agr;–mediated expression of E-selectin, vascular cell adhesion molecule-1, intercellular cell adhesion molecule-1, monocyte chemoattractant protein-1, interleukin-8, and the cytokine-mediated adhesion of monocytes to ECs. The antiinflammatory action of FIR was mimicked by bilirubin, and was reversed by the HO inhibitor, tin protoporphyrin-IX, or by the selective knockdown of HO-1. Finally, the antiinflammatory effect of FIR was also observed in patients undergoing hemodialysis. Conclusions—These results demonstrate that FIR therapy exerts a potent antiinflammatory effect via the induction of HO-1. The ability of FIR therapy to inhibit inflammation may play a critical role in preserving blood flow and patency of AVFs in hemodialysis patients.

Tuberculosis in maintenance dialysis patients

In this investigation, we tried to find the incidence and characteristics of tuberculosis (TB) in dialysis patients previously found only in a small number of cases. We collected the cases of newly diagnosed TB patients in Taiwan during 1997. Simultaneously, all dialysis patients were collected and matched with the TB cases to identify the dialysis patients who had also contracted TB. The annual incidence of the dialysis population was 493.4/100,000, 6.9 times that of the general population (71.1/100,000). The annual incidence for the male dialysis population was 573.3, the incidence was 479.2 for the female dialysis population. The incidence for the general population was 97.1 and 43.7/100,000, respectively. Although the 1-year mortality rate due to TB (1.7 vs. 1.9%, p > 0.05) was similar in both populations, the non-TB mortality was much higher in the dialysis population than that in the general population (25.6 vs. 11.1%, p < 0.05). Finally, the 1-year mortality rate of dialysis patients with TB is 3.3 times higher than that in dialysis patients without TB (27.3 vs. 8.3%, p < 0.05). The findings suggest that uremia modifies the behavior of TB, jeopardizes female and younger dialysis patients, poses a higher risk of extrapulmonary dissemination, and predicts a higher overall mortality.

Acute kidney injury network classification predicts in-hospital and long-term mortality in patients undergoing elective coronary artery bypass grafting surgery

OBJECTIVE Acute kidney injury (AKI) is a highly prevalent complication after cardiac surgery. It is associated with substantial morbidity and mortality. However, the definition of AKI has not been well established until the Acute Kidney Injury Network group outlined an easily used consentaneous staging system. The study aims to evaluate the association between this determination and in-hospital as well as long-term mortality in patients receiving elective coronary artery bypass grafting (CABG) surgery. METHODS Patients undergoing elective CABG surgery from January 2003 to December 2007 in a tertiary medical center were studied. The Acute Kidney Injury Network classification was applied for the diagnosis of perioperative AKI. Medical history and intra-operative variables were collected retrospectively. Multivariate analysis was used to identify the independent risk factors of in-hospital and long-term mortality. Long-term survival rates were calculated using the Kaplan-Meier method. RESULTS This study included 964 patients. The incidence of AKI following elective CABG was 19.8%. Only 7% of the study population developed AKI requiring renal replacement therapy after surgery. The overall in-hospital mortality rate was 5.1%. Significant independent risk factors for in-hospital mortality include increasing age, higher serum uric acid, postoperative requirement of intra-aortic balloon pumping (IABP) and extracorporeal membrane oxygenation (ECMO), perioperative AKI, and chronic dialysis (all p<0.05). Significant independent risk factors for long-term mortality include increasing age, lower serum albumin, higher serum uric acid, postoperative requirement of IABP and ECMO, perioperative AKI, and chronic dialysis (all p < 0.005). CONCLUSIONS Acute Kidney Injury Network classification is a powerful tool to evaluate the prognostic impact of AKI on both in-hospital and long-term mortality among patients undergoing elective CABG surgery.

Long-Term Clinical Outcome of Major Adverse Cardiac Events in Survivors of Infective Endocarditis A Nationwide Population-Based Study

Background— Substantial infective endocarditis (IE)–related morbidity and mortality may occur even after successful treatment. However, no previous study has explored long-term hard end points (ie, stroke, myocardial infarction, heart failure, cardiovascular death) in addition to all-cause mortality in IE survivors. Methods and Results— A nationwide population-based cohort study was conducted among IE survivors identified with the use of the Taiwan National Health Insurance Research Database during 2000 to 2009. IE survivors were defined as those who survived after discharge from first hospitalization with a diagnosis of IE. A total of 10 116 IE survivors were identified. IE survivors were matched to control subjects without IE at a 1:1 ratio through the use of propensity scores. The primary outcomes were stroke, myocardial infarction, readmission for heart failure, and sudden cardiac death or ventricular arrhythmia. The secondary outcomes were repeat IE and all-cause mortality. Compared with the matched cohort, IE survivors had higher risks of ischemic stroke (adjusted hazard ratio [aHR], 1.59; 95% confidence interval [CI], 1.40–1.80), hemorrhagic stroke (aHR, 2.37; 95% CI, 1.90–2.96), myocardial infarction (aHR, 1.44; 95% CI, 1.17–1.79), readmission for heart failure (aHR, 2.24; 95% CI, 2.05–2.43), sudden death or ventricular arrhythmia (aHR, 1.69; 95% CI, 1.44–1.98), and all-cause death (aHR, 2.27; 95% CI, 2.14–2.40). Risk factors for repeat IE were older age, male sex, drug abuse, and valvular replacement after an initial episode of IE. Conclusion— Despite treatment, the risk of long-term major adverse cardiac events was substantially increased in IE survivors.

Lanthanum carbonate (Fosrenol) efficacy and tolerability in the treatment of hyperphosphatemic patients with end-stage renal disease.

AIMS High serum phosphorus levels are a common problem in patients receiving long-term dialysis treatment. Lanthanum carbonate (Fosrenol) is a new non-aluminum, non-calcium phosphate binder developed for the treatment of hyperphosphatemia in patients with end-stage renal disease (ESRD). We report data from a recent trial, which, for the first time, assessed the efficacy and tolerability of lanthanum carbonate treatment, compared with placebo, in Chinese patients with ESRD. PATIENTS AND METHODS Following a one- to three-week washout phase and a four-week, open-label lanthanum carbonate dose-titration phase, male and female hemodialysis patients were randomized (1:1) to receive either lanthanum carbonate or placebo for four weeks. The primary efficacy parameter of the study was the control of serum phosphorus levels (< or =1.8 mmol/l [< or = 5.6 mg/dl]). Secondary endpoints included the profile of serum phosphorus during titration and parathyroid hormone, calcium, and calcium x phosphorus (Ca x P) product levels. The safety and tolerability of lanthanum carbonate were assessed by monitoring adverse events throughout the study. RESULTS Mean serum phosphorus level at the end of washout was 2.5 +/- 0.5 mmol/l (7.7 +/- 1.5 mg/dl; n=73), and there was no evidence of a difference in levels between the treatment groups pre-randomization. At the end of the study, lanthanum carbonate-treated patients had significantly lower phosphorus levels (1.6 +/- 0.5 mmol/l [5.1 +/- 1.5 mg/dl]; n=30) than those receiving placebo (2.3 +/- 0.4 mmol/l [7.2 +/- 1.3 mg/dl]; n=31; p < 0.001). In addition, a significantly higher proportion of patients receiving lanthanum carbonate had controlled serum phosphorus levels (60%) compared with the placebo group (10%; p < 0.001). Ca x P product levels were also significantly lower in the lanthanum carbonate group at the end of randomized treatment (p < 0.001). Lanthanum carbonate was well tolerated; only one serious adverse event was reported, which was unrelated to treatment. CONCLUSIONS Lanthanum carbonate was shown to be an effective and well-tolerated phosphate binder for the treatment of hyperphosphatemia in Chinese patients with ESRD. This finding supports the results of previous US and European studies, which have also shown that lanthanum carbonate treatment effectively controls serum phosphorus levels.

Matrix metalloproteinase-9 deficiency attenuates diabetic nephropathy by modulation of podocyte functions and dedifferentiation

Diabetic nephropathy is characterized by excessive deposition of extracellular matrix protein and disruption of the glomerular filtration barrier. Matrix metalloproteinases (MMPs) affect the breakdown and turnover of extracellular matrix protein, suggesting that altered expression of MMPs may contribute to diabetic nephropathy. Here we used an MMP-9 gene knockout mouse model, with in vitro experiments and clinical samples, to determine the possible role of MMP-9 in diabetic nephropathy. After 6 months of streptozotocin-induced diabetes, mice developed markedly increased albuminuria, glomerular and kidney hypertrophy, and thickening of the glomerular basement membrane. Gelatin zymographic analysis and western blotting showed that there was enhanced MMP-9 protein production and activity in the glomeruli. However, MMP-9 knockout in diabetic mice significantly attenuated these nephropathy changes. In cultured podocytes, various cytokines related to diabetic nephropathy including TGF-β1, TNF-α, and VEGF stimulated MMP-9 secretion. Overexpression of endogenous MMP-9 induced podocyte dedifferentiation. MMP-9 also interrupted podocyte cell integrity, promoted podocyte monolayer permeability to albumin, and extracellular matrix protein synthesis. In diabetic patients, the upregulation of urinary MMP-9 concentrations occurred earlier than the onset of microalbuminuria. Thus, MMP-9 seems to play a role in the development of diabetic nephropathy.

Increased risk of mortality in the elderly population with late-stage chronic kidney disease: a cohort study in Taiwan

BACKGROUND Taiwan has the worlds highest incidence and second highest prevalence of end-stage renal disease (ESRD), particularly in older age groups. However, the transition from chronic kidney disease (CKD) to death or ESRD remains unclear. This study aimed to investigate the impact of late-stage CKD on all-cause and cause-specific mortality by identifying the CKD population. METHODS This was an observational cohort study (n = 35 529), mean age 75.7 years (SD = 5.3), of participants in the Elderly Health Examination Program (EHEP) in Kaohsiung City, Taiwan, between 2002 and 2004. Estimated glomerular filtration rate (eGFR) was calculated by the simplified modified diet in renal disease equation. Proportional hazard ratios (HR) of mortality associated with late-stage CKD were assessed by Cox regression. RESULTS The crude prevalence rate of CKD stages 3-5 was 39.4%; 1840 participants (5.18%) died within 2-year follow-up, a mortality rate of 20.3 per 1000 person-years overall and 16.4 per 1000 person-years in the reference group. Higher HR for all-cause and cause-specific mortality were found in the groups with decreased eGFR. Compared with the reference group (eGFR > 60 mL/min/1.73 m(2)), adjusted HR for all-cause mortality were 1.5, 2.1 and 2.6 for groups with eGFR 30-44, 15-29 and < 15 mL/min/ 1.73 m(2), respectively (P < 0.001). Higher HR of mortality due to cardiovascular or renal diseases were also significantly associated with decreased eGFR (P < 0.05). CONCLUSION Late-stage CKD is a significant risk factor for mortality, especially due to cardiovascular and renal diseases, in elderly Taiwanese. Given the higher prevalence rate of late-stage CKD in the study area, CKD patient mortality was relatively lower, which might reflect underestimation of renal function for patients at early stages of CKD, or partly explain the high ESRD population.