Jhi-Joung Wang

Reverse Epidemiology of Hypertension-Mortality Associations in Hemodialysis Patients: A Long-Term Population-Based Study

BACKGROUNDnAlthough hypertension (HTN) is a predictor of mortality, recent data have questioned the link between baseline HTN and mortality in incident hemodialysis (HD) patients. We used Taiwans National Health Insurance claim data (NHRI-NHIRD-99182) to investigate the association.nnnMETHODSnIn 1999, this longitudinal cohort study enrolled 5752 new HD patients. Follow-up began from the initiation of HD until death, the end of HD, or the end of 2008. A Kaplan-Meier survival analysis was done. Cox proportional hazard analysis was used to identify the risk factors for mortality.nnnRESULTSnThe prevalence of baseline HTN was 75.47%. Patients with HTN had a higher prevalence of diabetic mellitus (DM) and cardiovascular diseases. The 1-, 5-, and 9-year cumulative survival rates were 95.5, 63.7 and 41.8% in patients with HTN, and 95.5, 71.0, and 52.0% in those without HTN (log-rank test: P <0.001). Multivariate analysis showed that patients with baseline HTN may have a higher survival rate (hazard ratio (HR) 0.901, 95% confidence interval (CI): 0.819-0.992). After stratification by age and DM, only elderly (≥65) patients without DM had a significantly higher survival rate (HR 0.769, 95% CI: 0.637-0.927). HTN predicts lower mortality with increasing age in patients with congestive heart failure (CHF) or coronary artery disease (CAD).nnnCONCLUSIONSnThere is a reverse (counterintuitive) association between baseline HTN and mortality in elderly HD patients without DM and a clear tendency for a reverse association with increasing age in patients with CHF or CAD. Further study of the association between HTN and mortality in older HD patients may be warranted.

Long-term survival and predictors for mortality among dialysis patients in an endemic area for chronic liver disease: a national cohort study in Taiwan

BackgroundPatients with end-stage renal disease (ESRD) are at a higher risk for chronic hepatitis, liver cirrhosis (LC) and mortality than the general population. Optimal modalities of renal replacement therapy for ESRD patients with concomitant end-stage liver disease remain controversial. We investigated the long-term outcome for chronic liver disease among dialysis patients in an endemic area.MethodsUsing Taiwan’s National Health Insurance claim data (NHRI-NHIRD-99182), We performed a longitudinal cohort study to investigate the impact of comorbidities on mortality in dialysis patients. We followed up 11293 incident hemodialysis (HD) and 761 peritoneal dialysis (PD) patients from the start of dialysis until the date of death or the end of database period (December 31, 2008). A Cox proportional hazards model was used to identify the risk factors for all-cause mortality.ResultsPatients receiving PD tended to be younger and less likely to have comorbidities than those receiving HD. At the beginning of dialysis, a high prevalence rate (6.16u2009%) of LC was found. Other than well-known risk factors, LC (hazard ratio [HR] 1.473, 95u2009% CI: 1.329-1.634) and dementia (HR 1.376, 95u2009% CI: 1.083-1.750) were also independent predictors of mortality. Hypertension and mortality were inversely associated. Dialysis modality and three individual comorbidities (diabetes mellitus, chronic lung disease, and dementia) interacted significantly on mortality risk.ConclusionsLC is an important predictor of mortality; however, the effect on mortality was not different between HD and PD patients.

Predictors of Longterm Mortality in Patients with and without Systemic Lupus Erythematosus on Maintenance Dialysis: A Comparative Study

Objective. To compare the prognosis of patients with and without systemic lupus erythematosus (SLE) on dialysis and to determine the factors that affect survival after dialysis. Methods. We used the Taiwan National Health Insurance Research Database (NHRI-NHIRD-99182) and collected data on patients who started maintenance dialysis between 2001 and 2003. Patients were followed from the initiation of dialysis until death, discontinuation of dialysis, or the end of 2008. We did a Kaplan-Meier analysis of the cohort and used multivariate Cox regression analysis to identify significant predictors of survival. Results. Of the 22,394 dialysis patients studied, 303 (1.35%) had SLE. Hypertension and diabetes were the 2 most common comorbidities associated with dialysis for patients with and without SLE. After adjusting for age, sex, dialysis modality, and comorbidities, we found no significant survival difference between the 2 patient groups after 8 years of followup. Multivariate analysis showed that increased mortality in the patient group without SLE (p < 0.05) was associated with older age (≥ 45 years), male sex, initial choice of hemodialysis, diabetes mellitus, heart failure, coronary artery disease, cerebrovascular disease, and malignancy. In the patient group with SLE, independent predictors of mortality (p < 0.05) were older age (≥ 65 years), male sex, and diabetes mellitus. Conclusion. The longterm survival outcome was similar between patients with and without SLE who were on dialysis. The factors affecting patient mortality were not identical in these 2 groups.

Epidemiology and mortality among dialysis patients with acute coronary syndrome: Taiwan National Cohort Study

BACKGROUNDnPatients with end-stage renal disease (ESRD) on dialysis have poor outcomes after acute coronary syndrome (ACS). Epidemiological data for Asian patients are scarce.nnnMETHODSnThis longitudinal cohort study investigated the incidence, risk factors, and outcomes of ACS in 19,974 ESRD incident dialysis patients in the Taiwan National Health Insurance research Database between January 1999 and December 2001. The follow-up period was from the start of dialysis to the date of death, end of dialysis, or December 31, 2008.nnnRESULTSnACS was diagnosed in 1785 patients during follow-up (1.78/100 person-years): 832 (46.6%) had acute myocardial infarction (AMI), 681 (38.2%) underwent cardiac catheterization, 398 (22.3%) underwent percutaneous transluminal coronary angioplasty (PTCA), and 50 (2.8%) underwent coronary artery bypass grafting. Male (HR 1.35, 95% CI: 1.23-1.49) and elderly (HR 3.289, 95% CI: 2.71-4.00) patients had a high rate of ACS. Patients with baseline comorbidities (diabetes mellitus, hypertension, congestive heart failure, coronary artery disease, dysrhythmia, and other cardiac and chronic obstructive lung diseases) had a higher incidence of ACS than did those without. Overall in-hospital mortality was 9.7%. The cumulative 6-month post-hospitalization survival rate was 79.3%; the 1-year rate was 72.3%. Being elderly (≥ 65 years old), and having DM or AMI were associated with an increased risk for mortality; PTCA was associated with a decreased risk (HR 0.77, 95% CI: 0.66-0.91).nnnCONCLUSIONnESRD dialysis patients had a high incidence of ACS and mortality. Being male, elderly and having baseline comorbidities were independent risk factors for ACS. Coronary intervention is the possible benefits for dialysis patients.

Dual view capsule endoscopic lens design

A dual view capsule endoscopic (DVCE) lens is proposed with front view and back view functions. This is a hybrid lens with a catadioptric mirror and an aspherical surface to support both view functions. The field of view (FOV) for the front view function is 90 degrees. The FOV for the back view function is 260 to 290 degrees. The TV distortion for the front view and back view function is under 30% and 25%. The corner relative illuminations for the two view functions are above 0.53. The Modulation Transfer Function (MTF) performance at the Nyquist Frequency for the two view functions can be kept above 0.35, even under tolerance they can remain above 0.2. Moreover, the telecentric conditions at the image plane of the DVCE system can support constant magnification through focusing. This condition can reduce the measurement error by slightly defocusing of the lens. Thus, the two view functions can offer physicians a wide viewing angle to deal with lesions over the fold.

Epidemiologic features and long-term outcome of dialysis patients with infective endocarditis in Taiwan

BACKGROUNDnThe incidence of infective endocarditis (IE) is high in dialysis patients. Limited data are available on the risk factors for IE and long-term outcome after IE in dialysis patients, especially in Asian populations.nnnMETHODSnWe used Taiwan National Health Insurance Research Database to design a longitudinal cohort study. 68,426 ESRD patients who began dialysis between 1999 and 2007 were included. The follow-up period was from the start of dialysis to death, end of dialysis, or end of 2008. Cox proportional hazards models were used to identify the risk factors for IE.nnnRESULTSnIE was diagnosed in 502 patients during follow-up (201.4 per 100,000 person-years). Diabetes mellitus (DM), congestive heart failure (CHF), cerebro-vascular accident (CVA), and rheumatic heart disease (RHD) (HR: 3.07, 95% CI: 1.99-4.75) were associated with an increasing risk of development of IE. The cumulative incidence rate of IE in patients with RHD was 1.4, 2.2, and 3.9% at 1, 3, and 5 years. In-hospital mortality was 23.5%. Cumulative survival rates post-IE were 54.3% at 1 year and only 35.3% at 5 years.nnnCONCLUSIONnDialysis patients had a higher risk of IE. Those who were older and had DM, CHF, CVA, or especially RHD were at a greater risk. Dialysis patients with IE also had high mortality.

The impact of comorbidity on survival after hemorrhagic stroke among dialysis patients: a nationwide population-based study

BackgroundThis study was aimed at determining the outcome and examining the association between comorbidities and mortality after intracerebral hemorrhage in chronic dialysis patients.MethodsWe used the Taiwan National Health Insurance Research Database and enrolled patients who underwent maintenance dialysis between 2000 and 2007. Annual incidence of intracerebral hemorrhage in patients receiving dialysis from 2000 to 2007 was determined. To identify predictors of hemorrhagic stroke, we used logistic regression model to estimate the relative ratio of factors for intracerebral hemorrhage in the most recent cohort (2007). The cumulative survival rate and comorbid conditions associated with mortality after intracerebral hemorrhage among all dialysis patients between 2000 and 2007 was calculated using the Kaplan-Meier method and Cox regression analysis.ResultsWe identified 57,261 patients on maintenance dialysis in the cohort of 2007, and 340 patients had history of intracerebral hemorrhage among them. Hypertension was the most common comorbidity of dialysis patients. The incidence rate of intracerebral hemorrhage among dialysis patients was about 0.6%. Adjusted logistic regression model showed that male gender, middle age (45–64 years), hypertension, and previous history of stroke were the independent predictors for the occurrence of intracerebral hemorrhage among chronic dialysis patients. 1,939 dialysis patients with development of intracerebral hemorrhage in the analysis period from 2000 to 2007 were identified. In-hospital mortality was high (36.15%) following intracerebral hemorrhage. They were followed up after intracerebral hemorrhage for a mean time of 41.56xa0months. Adjusted Cox regression analyses demonstrated that the factors independently associated with mortality after intracerebral hemorrhage among dialysis patients included diabetes mellitus, malignancy and a history of prior stroke.ConclusionsDialysis patients who have history of prior stroke, diabetes and malignancy have worse survival than patients without these comorbidities. Attention must focus on providing optimal medical care after hemorrhagic stroke for these target groups to reduce mortality.

Brain tissue oxygen evaluation by wireless near-infrared spectroscopy

BACKGROUNDnMonitoring the partial pressure of oxygen in brain tissue (PbtO2) is an important tool for traumatic brain injury (TBI) but is invasive and inconvenient for real time monitoring. Near-infrared spectroscopy (NIRS), which can monitor hemoglobin parameters in the brain tissue, has been used widely as a noninvasive tool for assessing cerebral ischemia and hypoxia. Therefore, it may have the potential as a noninvasive tool for estimating the change of PbtO2. In this study, a novel wireless NIRS system was designed to monitor hemoglobin parameters of rat brains under different impact strengths and was used to estimate the change of PbtO2 noninvasively in TBI.nnnMATERIALS AND METHODSnThe proposed wireless NIRS system and a PbtO2 monitoring system were used to monitor the oxygenation of rat brains under different impact strengths. Rats were randomly assigned to four different impact strength groups (sham, 1.6 atm, 2.0 atm, and 2.4 atm; n = 6 per group), and the relationships of concentration changes in oxyhemoglobin (HbO2), deoxyhemoglobin (HbR), and total hemoglobin (HbT), and PbtO2 during and after TBI with different impact strengths were investigated. Triphenyltetrazolium chloride (TTC) staining was also used to evaluate infarction volume.nnnRESULTSnConcentration changes in HbO2, HbR, and HbT dropped immediately after the impact, increased gradually, and then became stable. Changes in PbtO2 had a similar tendency with the hemoglobin parameters. There was significant correlation between changes in PbtO2 and HbO2 (correlation = 0.76) but not with changes in HbR (correlation = 0.06). In triphenyltetrazolium chloride staining, the infarction volume was highly but negatively associated with oxygen-related parameters like PbtO2 and HbO2.nnnCONCLUSIONSnChanges in HbO2 under TBI was highly and positively correlated with changes in PbtO2. By using the relative changes in HbO2 as a reference parameter, the proposed wireless NIRS system may be developed as a noninvasive tool for estimating the change of PbtO2 in brain tissue after TBI.

Wireless near-infrared spectroscopy system for determining brain hemoglobin levels in laboratory animals

Traumatic brain injury (TBI) is usually caused by brain shaking or impact. It can affect normal brain function and may even lead to disability or death. However, there are very few studies on the associated physiologic changes in humans or animals. In this study, a non-invasive, wireless multi-channel near-infrared spectroscopy (NIRS) was developed to continuously monitor the concentration change of oxyhemoglobin (HbO2), deoxyhemoglobin (HbR), and total hemoglobin (HbT) to elucidate changes in the physiological state of the brain during and after different strength impaction. The triphenyltetrazolium chloride (TTC) staining was also used to monitor changes of infarction volume after different strength impaction. The results indicated that the concentration changes of HbO2 and HbT, and the changes of infarction volumes were significantly related to the impact strength. In conclusion, the status of TBI can be clinically evaluated by detecting HbO2 and HbT changes. The system proposed here is stable, accurate, non-invasive, and mostly important wireless which can easily be used for TBI study.

Design of a bi-directional illumination system for a dual view capsule endoscope

ABSTRACT The capsule endoscope is an important tool for the intestinal examination. But the main disadvantage of the traditional capsule endoscope is the limited field of view. In order to solve this problem, the dual view capsule endoscope (DVCE) was developed. In this work, a dual view illumination system is designed for a DVCE. The dual view illumination system is divided into two sub-systems with a front view illumination lens and a back view illumination lens. The Bézier curves for the front view and back view illumination lenses are used for optimization, based on which we change the radiation pattern of the LED so that the dual view illumination design can support energy for the front view and back view simultaneously while achieving low power consumption and high efficiency. Moreover, a non-uniform illumination process is used to compensate for the problem of uniformity and relative illumination for the DVCE lens. Through this design, we can obtain a uniformity of 91% and an efficiency of 25.2% for front view illumination and uniformity of 91% and an efficiency of 23.5% for back view illumination. Finally, tolerance analysis can also be completed for mass production.