Prediction of Intradialytic Blood Pressure Variation Based on Big Data.

INTRODUCTION: Cardiovascular (CV) events are the major cause of morbidity and mortality associated with blood pressure (BP) in hemodialysis (HD) patients. BP varies significantly during HD treatment, and the dramatic variation in BP is a well-recognized risk factor for increased mortality. The development of an intelligent system capable of predicting BP profiles for real-time monitoring is important. Our aim was to build a web-based system to predict changes in systolic BP (SBP) during HD. METHODS: In this study, dialysis equipment connected to the Vital Info Portal gateway collected HD parameters that were linked to demographic data stored in the hospital information system. There were 3 types of patients: training, test, and new. A multiple linear regression model was built using the training group with SBP change as the dependent variable and dialysis parameters as the independent variables. We tested the model's performance on test and new patient groups using coverage rates with different thresholds. The model's performance was visualized using a web-based interactive system. RESULTS: A total of 542,424 BP records were used for model building. The accuracy was greater than 80% in the prediction error range of 15%, and 20 mm Hg of true SBP in the test and new patient groups for the model of SBP changes suggested the good performance of our prediction model. In the analysis of absolute SBP values (5, 10, 15, 20, and 25 mm Hg), the accuracy of the SBP prediction increased as the threshold value increased. DISCUSSION: This databae supported our prediction model in reducing the frequency of intradialytic SBP variability, which may help in clinical decision-making when a new patient receives HD treatment. Further investigations are needed to determine whether the introduction of the intelligent SBP prediction system decreases the incidence of CV events in HD patients.

Results of Fabry Disease Screening in Male Pre-End Stage Renal Disease Patients with Unknown Etiology Found Through the Platform of a Chronic Kidney Disease Education Program in a Northern Taiwan Medical Center.

BACKGROUND/AIMS: Fabry disease (FD), a rare x-lined genetic disorder is a cause of renal deterioration. The phenotype of FD is highly variable and nonspecific, and correct diagnosis has always been delayed. We aimed to explore the prevalence and clinical presentation of FD in this high-risk male population in a Northern Taiwan medical center. METHODS: This is the first study to survey the incidence of FD in this high-risk population through the platform of a chronic kidney disease (CKD) education program in Asia. A total of 1,012 male patients with unknown CKD causes were screened using an assay of alpha-galactosidase A activity (α-Gal A) by dried blood spots (DBS). A final GLA gene analysis was also done for those with low enzyme activity. RESULTS: We identified two new patients with classic FD and four patients with late-onset FD. One novel GLA mutation with c.413 G>A was found in one classic FD patient (index 5). The prevalence of FD is about 0.59 % (6 in 1,012) in the high-risk population group with CKD. The clinical symptoms of FD patients are nonspecific except in those with various degrees of renal failure. Those patients' correct diagnosis was delayed, taking years and even decades. Three patients received enzyme replacement therapy and one started regular hemodialysis due to persistent renal function deterioration. Another two patients were found from family screening through a new index. In addition, a false negative result occurred in one patient who was proved to have FD by his kidney pathology as determined by this screening. CONCLUSION: FD is not such as rare a disease and its prevalence is greater in this high-risk male population. Clinicians need to be aware that FD should be included in the differential diagnosis in CKD with unknown etiology.

Intelligent system to predict intradialytic hypotension in chronic hemodialysis.

BACKGROUND: Intradialytic hypotension (IDH) is a serious complication and a major risk factor of increased mortality during hemodialysis (HD). However, predicting the occurrence of intradialytic blood pressure (BP) fluctuations clinically is difficult. This study aimed to develop an intelligent system with capability of predicting IDH. METHODS: In developing and training the prediction models in the intelligent system, we used a database of 653 HD outpatients who underwent 55,516 HD treatment sessions, resulting in 285,705 valid BP records. We built models to predict IDH at the next BP check by applying time-dependent logistic regression analyses. RESULTS: Our results showed the sensitivity of 86% and specificity of 81% for both nadir systolic BP (SBP) of <90 mmHg and <100 mmHg, suggesting good performance of our prediction models. We obtained similar results in validating via test data and data of newly enrolled patients (new-patient data), which is important for simulating prospective situations wherein dialysis staff are unfamiliar with new patients. This compensates for the retrospective nature of the BP records used in our study. CONCLUSION: The use of this validated intelligent system can identify patients who are at risk of IDH in advance, which may facilitate well-timed personalized management and intervention.

Indoxyl Sulfate Impairs Endothelial Progenitor Cells and Might Contribute to Vascular Dysfunction in Patients with Chronic Kidney Disease.

BACKGROUND/AIMS: Indoxyl sulfate (IS) is a protein-bound uremic toxin that accumulates in patients with chronic kidney disease (CKD). We explored the effect of IS on human early endothelial progenitor cells (EPCs) and analyzed the correlation between serum IS levels and parameters of vascular function, including endothelial function in a CKD-based cohort. METHODS: A cross-sectional study with 128 stable CKD patients was conducted. Flow-mediated dilation (FMD), pulse wave velocity (PWV), ankle brachial index, serum IS and other biochemical parameters were measured and analyzed. In parallel, the activity of early EPCs was also evaluated after exposure to IS. RESULTS: In human EPCs, a concentration-dependent inhibitory effect of IS on chemotactic motility and colony formation was observed. Additionally, serum IS levels were significantly correlated with CKD stages. The total IS (T-IS) and free IS (F-IS) were strongly associated with age, hypertension, cardiovascular disease, blood pressure, PWV, blood urea nitrogen, creatine and phosphate but negatively correlated with FMD, the estimated glomerular filtration rate (eGFR), hemoglobin, hematocrit, and calcium. A multivariate linear regression analysis also showed that FMD was significantly associated with IS after adjusting for other confounding factors. CONCLUSIONS: In humans, IS impairs early EPCs and was strongly correlated with vascular dysfunction. Thus, we speculate that this adverse effect of IS may partly result from the inhibition of early EPCs.

Indoxyl sulfate, not P-cresyl sulfate, is associated with advanced glycation end products in patients on long-term hemodialysis.

BACKGROUND/AIMS: Advanced glycation end products (AGEs) are pro-inflammatory and pro-oxidative compounds that play a critical role in endothelial dysfunction and atherosclerosis. Protein-bound uremic toxins, indoxyl sulfate (IS) and p-cresyl sulfate (PCS), inhibit endothelial function. We explored the association of IS and PCS with AGEs in a hemodialysis (HD) cohort. METHODS: This study was a cross-sectional study that recruited 129 stable patients on maintenance HD in a single medical center from July 1 to July 15, 2011. Serum levels of total and free IS, PCS and AGEs were measured concurrently. General laboratory results and patient background were also investigated. RESULTS: Serum levels of AGEs were associated with total IS (r = 2.7, p < 0.01) but not total PCS (r = 0.01, NS), free IS (r = 0.11, NS) or free PCS (r = 0.04, NS) using Pearson's analysis. Multiple linear regression analysis showed that total IS was significantly related to AGEs (ß = 0.296, p < 0.01), free IS (ß = 0.502, p < 0.01) and creatinine (ß = 0.294, p < 0.01). Serum AGEs levels were also independently correlated with diabetes status (ß = 0.250, p = 0.01) and total IS (ß = 0.341, p < 0.01) concentrations after adjusting for other confounding variables. Moreover, patients with diabetes had higher serum AGEs levels than patients without diabetes (p < 0.01). CONCLUSIONS: These findings suggest that serum levels of total IS were associated with AGEs levels, which may participate in the process of atherosclerosis.

Bicarbonate can improve the prognostic value of the MELD score for critically ill patients with cirrhosis.

The prognosis of critically ill patients with cirrhosis is poor. Our aim was to identify an objective variable that can improve the prognostic value of the Model of End-Stage Liver Disease (MELD) score in patients who have cirrhosis and are admitted to the intensive care unit (ICU). This retrospective cohort study included 177 patients who had liver cirrhosis and were admitted to the ICU. Data pertaining to arterial blood gas-related parameters and other variables were obtained on the day of ICU admission. The overall ICU mortality rate was 36.2%. The bicarbonate (HCO3) level was found to be an independent predictor of ICU mortality (odds ratio, 2.3; 95% confidence interval [CI], 1.0-4.8; p = 0.038). A new equation was constructed (MELD-Bicarbonate) by replacing total bilirubin by HCO3 in the original MELD score. The area under the receiver operating characteristic curve for predicting ICU mortality was 0.76 (95% CI, 0.69-0.84) for the MELD-Bicarbonate equation, 0.73 (95% CI, 0.65-0.81) for the MELD score, and 0.71 (95% CI, 0.63-0.80) for the Acute Physiology and Chronic Health Evaluation II score. Bicarbonate level assessment, as an objective and reproducible laboratory test, has significant predictive value in critically ill patients with cirrhosis. In contrast, the predictive value of total bilirubin is not as prominent in this setting. The MELD-Bicarbonate equation, which included three variables (international normalized ratio, creatinine level, and HCO3 level), showed better prognostic value than the original MELD score in critically ill patients with cirrhosis.

Effect of Low Protein Diet Supplemented with Ketoanalogs on Endothelial Function and Protein-Bound Uremic Toxins in Patients with Chronic Kidney Disease.

Studies have demonstrated that a low-protein diet supplemented with ketoanalogs (KAs) could significantly retard progression of renal function in patients with chronic kidney disease (CKD) stages 3-5. However, its effects on endothelial function and serum levels of protein-bound uremic toxins remain elusive. Therefore, this study explored whether a low-protein diet (LPD) supplemented with KAs affects kidney function, endothelial function, and serum uremic toxin levels in a CKD-based cohort. In this retrospective cohort, we enrolled 22 stable CKD stage 3b-4 patients on LPD (0.6-0.8 g/day). Patients were categorized into control (LPD only) and study groups (LPD + KAs 6 tab/day). Serum biochemistry, total/free indoxyl sulfate (TIS/FIS), total/free p-cresyl sulfate (TPCS/FPCS), and flow-mediated dilation (FMD) were measured before and after 6 months of KA supplementation. Before the trial, there were no significant differences in kidney function, FMD, or uremic toxin levels between the control and study groups. When compared with the control group, the paired t-test showed a significant decrease in TIS and FIS (all p < 0.05) and a significant increase in FMD, eGFR, and bicarbonate (all p < 0.05). In multivariate regression analysis, an increase in FMD (p < 0.001) and a decrease in FPCS (p = 0.012) and TIS (p < 0.001) remained persistent findings when adjusted for age, systolic blood pressure (SBP), sodium, albumin, and diastolic blood pressure (DBP). LPD supplemented with KAs significantly preserves kidney function and provides additional benefits on endothelial function and protein-bound uremic toxins in patients with CKD.

Plasma selenium and zinc alter associations between nephrotoxic metals and chronic kidney disease: Results from NHANES database 2011-2018.

Introduction: Chronic kidney disease (CKD) is a condition defined as a persistent change in kidney structure or function, or both, that compromises human health. Environmental exposure to heavy metals (e.g. cadmium, lead, arsenic and mercury) is common, and high exposure levels are known to cause nephrotoxicity. Micronutrients such as selenium and zinc are positively associated with better kidney function and renal outcomes. This study determined the associations between CKD and heavy metal exposures measured in blood or urine within a community-dwelling population, and assessed whether and how selenium and zinc modified the associations. Method: Data were extracted from 4 cycles of the US National Health and Nutrition Examination Survey (NHANES) database (2011-2012, 2013-2014, 2015-2016 and 2017-2018). Results: Univariate analysis showed that higher quartiles of plasma lead and cadmium concentration were more likely associated with CKD than the lowest quartile, and along with folate, were linked to greater odds of CKD. Conversely, as plasma selenium and serum zinc increased, the odds of CKD decreased. Multivariate analysis had similar results after adjusting for relevant confounders. Higher plasma cadmium quartiles were associated with higher odds of CKD. Associations between higher quartiles of plasma selenium and serum zinc were significantly associated with lower odds of CKD. Conclusion: Elevated blood levels of heavy metals increase CKD, whereas elevated concentrations of plasma selenium and serum zinc decrease CKD. A high serum zinc concentration appears to interact with low-toxicity heavy metals to reduce CKD risk. This study suggests that increased selenium and zinc in the body along with avoidance of heavy metal exposures could protect against CKD.

Absolute interdialytic weight gain is more important than percent weight gain for intradialytic hypotension in heavy patients.

AIM: Few published reports have mentioned the difference between absolute interdialytic weight gain (IDWG) and IDWG/DW (IDWG%), and subsequent effects on daily dialysis. The aim of present study was to evaluate the difference between absolute IDWG and IDWG% in new haemodialysis patients. METHOD: We retrospectively reviewed the records of 255 patients who recently received conventional haemodialysis for at least 1 year at the same centre from 1997 to 2008. The first 4 weeks after starting haemodialysis was defined as the pre-study period. Data were collected for 5-56 weeks. RESULTS: IDWG% value remained relatively constant in the first year of haemodialysis despite most patients having certain residual renal function. For haemodialysis outcomes, both absolute IDWG and IDWG% were significantly correlated with intradialytic hypotension (IDH) in men and heavy women. After dividing patients into four strata, which according to the gender and the median dry weight, stepwise multivariate linear regression analysis showed that absolute IDWG, rather than IDWG%, was an independent risk factor for IDH in heavy men (Beta = 0.585, P < 0.001) and heavy women (Beta= 0.458, P < 0.001). CONCLUSIONS: Absolute IDWG, rather than IDWG%, is an independent risk factor for IDH in heavy haemodialysis patients. Therefore, higher absolute IDWG needs to be strictly controlled despite the corresponding IDWG% possibly being relatively small in heavy haemodialysis patients.

Peripheral artery disease in peritoneal dialysis and hemodialysis patients: single-center retrospective study in Taiwan.

BACKGROUND: Peripheral artery disease (PAD) is a condition characterized by restricted blood flow to the extremities, and is especially common in the elderly. PAD increases the risk for mortality and morbidity in patients with end-stage renal disease (ESRD), especially those on hemodialysis (HD). METHODS: The records of 484 patients with end-stage renal disease who were on HD or peritoneal dialysis (PD) were reviewed. PAD was diagnosed based on the ankle-brachial pressure index (ABI). Demographic and clinical characteristics were analyzed. RESULTS: PAD had an overall prevalence of 18.2% and was significantly more common in HD patients (21.8%) than in PD patients (4.8%). Advanced age, diabetes mellitus, smoking, low parathyroid hormone level, elevated serum ferritin, elevated serum glucose, and low serum creatinine levels increased the risk for PAD. PAD was independently associated with advanced age, diabetes mellitus, duration of dialysis, low serum creatinine, and hyperlipidemia. PD patients had a significantly lower prevalence of PAD than HD patients, maybe due to their younger age and lower prevalence of diabetes mellitus in this present study. CONCLUSIONS: The prevalence of PAD was greater in the HD group than the PD group. Most of the risk factors for PAD were specific to HD, and no analyzed factor was significantly associated with PAD in PD patients.

Interdialytic weight gain does not influence the nutrition of new hemodialysis patients.

OBJECTIVE: The aim of the present study was to assess the relationship between interdialytic weight gain (IDWG) and nutrition markers in hemodialysis (HD) patients, by means of repeated measures analysis. METHODS: The records of 255 patients, who had recently received conventional HD for a minimum of 1 year, were retrospectively reviewed. Nutrition markers, including serum albumin, serum phosphate, blood urea nitrogen, and creatinine, were recorded at monthly intervals and subjected to repeated measures analysis. RESULTS: Patients with higher IDWG/dry weight (IDWG%) (>5%) had significantly lower body mass index throughout the study. Repeated measures analysis of variance indicated no significant difference in these nutrition markers for patients with different IDWG%. At the end of the study, neither IDWG nor IDWG% were found to be associated with albumin or phosphate, on linear regression analysis. CONCLUSIONS: There was no evidence of better nutrition in new HD patients with higher IDWG%. Although increased intake is promoted as critical for improving nutritional status in HD patients, it may be inappropriate to focus solely on the benefits of higher IDWG%, which can also lead to the development of hypertension, left ventricular hypertrophy, and intradialytic hypotension.

The characteristics of new semi-quantitative method for diagnosing proteinuria by using random urine samples.

We assessed the characteristics of the new semi-quantitative test paper (Clinitek ATLAS Pro(12)) using random urine samples. Three hundred urine samples were analyzed using either the new test paper, conventional dipsticks, quantitative (P/C ratio), or immunological quantitative methods (A/C ratio). Our study showed that the new test paper is highly sensitive and specific for the detection of urinary protein. The new test paper also detected the urine protein more accurately than the conventional test and has a lower false-positive rate. In addition, the new test paper detected 14 of the 300 patients (4.7%) as dilute urine samples needing reassessment. Seventeen of the 300 samples tested were negative with conventional dipsticks but positive with the new test paper. The new semi-quantitative test paper not only has higher sensitivity than the conventional dipstick method, but also has potential to detect dilute samples.

p-Cresylsulfate and indoxyl sulfate level at different stages of chronic kidney disease.

Indoxyl sulfate and p-cresylsulfate was associated with poor clinical outcome of uremia. We explored the relationship between the two toxins and renal function in chronic kidney disease (CKD) patients. This study enrolled 103 stable CKD patients (stage 3-5 and hemodialysis (HD) patients). Serum levels of indoxyl sulfate and p-cresylsulfate were measured using ultra performance liquid chromatography. General laboratory results and patient background were also checked. Patients with advanced CKD had higher serum indoxyl sulfate, p-cresylsulfate based on ANOVA test. There were significant correlation between indoxyl sulfate and p-cresylsulfate and serum creatinine after multivariate regression analysis (B=3.59, P<0.01; B=0.93, P=0.04, respectively). In addition, there was a positive correlation between indoxyl sulfate and p-cresylsulfate level (r=0.61, P<0.01). Indoxyl sulfate and p-cresylsulfate level increased gradually while renal function declined and reached the peak at the stage of HD. Serum indoxyl sulfate level was closely associated with p-cresylsulfate level in CKD patients.

Risk associated with estimated glomerular filtration rate and albuminuria for PAD among patients with type 2 diabetes.

Chronic kidney disease (CKD) is significantly associated with peripheral arterial disease (PAD) in some studies, but data on the association of the risk of PAD across a broad range of kidney function in patients with type 2 diabetes are limited. Between October 17, 2013 and February 7, 2015, all consecutive outpatients with type 2 diabetes underwent ankle-brachial index (ABI) examination. We investigated the association of estimated glomerular filtration rate (eGFR) and albumin-to-creatinine ratio (ACR) with the risk of PAD. A total of 1254 patients were cross-classified into 12 groups based on ACR category (normoalbuminuria, microalbuminuria and macroalbuminuria) and eGFR stage (≥90, 60-89, 30-59 and <30 mL/min/1.73 m2). Logistic regression analysis was used to investigate the association of eGFR and ACR with PAD. Within each ACR category, a lower eGFR stage was associated with PAD. Similarly, within each eGFR group, a higher ACR category was also associated with PAD. The OR for PAD was highest in patients with eGFR <30 mL/min/1.73 m2 and macroalbuminuria (OR 14.42, 95% CI 4.60 to 45.31) when compared with the reference group of subjects with eGFR ≥90 mL/min/1.73 m2 and normoalbuminuria. Our study found that cross-classification of eGFR with ACR revealed a more comprehensive association with risk of PAD than eGFR or ACR alone.

Serum protein-bound uraemic toxins and clinical outcomes in haemodialysis patients.

BACKGROUND: The protein-bound uraemic toxin p-cresol is associated with immunodeficiency in haemodialysis (HD) patients. We investigated the effect of serum p-cresol, indoxyl sulphate and other variables on clinical outcomes in HD patients during a 20-month follow-up. METHODS: We enrolled 100 stable HD patients from a single medical centre. The primary outcomes were infection-related hospitalization, cardiovascular events and all-cause mortality. Serum total and free p-cresol and indoxyl sulphate levels were measured using ultra-performance liquid chromatography. Biochemical data were collected concurrently. RESULTS: Multivariate logistic regression analysis revealed that infection-related hospitalization correlated with free p-cresol (adjusted odds ratio: 1.70, P = 0.01) and highly sensitive C-reactive protein (hsCRP) (adjusted odds ratio: 2.07, P = 0.01); cardiovascular event was associated with free p-cresol (adjusted odds ratio: 1.78, P = 0.01) and nPCR (adjusted odds ratio: 0.01, P = 0.02); and all-cause mortality was related to albumin (adjusted odds ratio: 0.04, P = 0.01). The Kaplan-Meier method showed that free and total p-cresol were significantly associated with cardiovascular events (log-rank P < 0.01 and log-rank P < 0.01, respectively). Serum free p-cresol seemed to have a trend to correlate with infection-related hospitalization during a 20-month follow-up (log-rank P = 0.05). CONCLUSIONS: Serum free and total p-cresol levels were significantly related to cardiovascular events. In addition, serum free p-cresol and hsCRP levels were also found to be associated with infection-related hospitalization.

Dataset supporting blood pressure prediction for the management of chronic hemodialysis.

Hemodialysis (HD) is a treatment given to patients with renal failure. Notable treatment-related complications include hypotension, cramps, insufficient blood flow, and arrhythmia. Most complications are associated with unstable blood pressure during HD. Physicians are devoted to seeking solutions to prevent or lower the incidence of possible complications. With advances in technology, big data have been obtained in various medical fields. The accumulated dialysis records in each HD session can be gathered to obtain big HD data with the potential to assist HD staff in increasing patient wellbeing. We generated a large stream of HD parameters collected from dialysis equipment associated with the Vital Info Portal gateway and correlated with the demographic data stored in the hospital information system from each HD session. We expect that the application of HD big data will greatly assist HD staff in treating intradialytic hypotension, setting optimal dialysate parameters, and even developing an intelligent early-warning system as well as providing individualized suggestions regarding dialysis settings in the future.

Association between trace element concentrations and anemia in patients with chronic kidney disease: a cross-sectional population-based study.

Anemia is common in chronic kidney disease (CKD) and may be affected by trace element concentrations. While the concentrations of trace elements are known to be altered in CKD, the relationship between trace element and hemoglobin concentrations has not been systematically investigated in a large cohort. This study aims to examine associations between trace element concentrations and anemia in patients with CKD. Data from the National Health and Nutrition Examination Survey collected from 2011 to 2014 were used for this analysis. The participants who were more than 20 years old were included. A total of 3057 participants were included; the final cohort was divided into two groups based on CKD status. The concentrations of hemoglobin, iron, zinc, and manganese were significantly lower in participants with than without CKD (all p<0.05). Multivariate analyses showed that in patients without CKD, hemoglobin concentrations correlated positively with iron, zinc, and cadmium (ß=0.005, 0.009, and 0.33, respectively), but correlated negatively with copper levels (ß=-0.002). In patients with CKD, hemoglobin concentrations correlated positively with cadmium and selenium, but negatively with copper levels (ß=0.57, 0.007, and -0.008, respectively). The serum iron concentration was found to correlate positively with zinc, cadmium, and selenium, but negatively with copper and manganese concentrations in the total study population (all p<0.05). The associations between serum concentrations of trace elements and hemoglobin differ between patients with and without CKD. Further investigations are warranted to determine whether patients with CKD have distinct trace element requirements.

The Paradoxical Role of Uric Acid in Osteoporosis.

Because of its high prevalence worldwide, osteoporosis is considered a serious public health concern. Many known risk factors for developing osteoporosis have been identified and are crucial if planning health care needs. Recently, an association between uric acid (UA) and bone fractures had been explored. Extracellular UA exhibits antioxidant properties by effectively scavenging free radicals in human plasma, but this benefit might be disturbed by the hydrophobic lipid layer of the cell membrane. In contrast, intracellular free oxygen radicals are produced during UA degradation, and superoxide is further enhanced by interacting with NADPH oxidase. This intracellular oxidative stress, together with inflammatory cytokines induced by UA, stimulates osteoclast bone resorption and inhibits osteoblast bone formation. UA also inhibits vitamin D production and thereby results in hyper-parathyroidism, which causes less UA excretion in the intestines and renal proximal tubules by inhibiting the urate transporter ATP-binding cassette subfamily G member 2 (ABCG2). At normal or high levels, UA is associated with a reduction in bone mineral density and protects against bone fracture. However, in hyperuricemia or gout arthritis, UA increases bone fracture risk because oxidative stress and inflammatory cytokines can increase bone resorption and decrease bone formation. Vitamin D deficiency, and consequent secondary hyperparathyroidism, can further increase bone resorption and aggravated bone loss in UA-induced osteoporosis.