Association of low serum aluminum level with mortality in hemodialysis patients

Bone aluminum accumulation in the current era

In the last few years, evidence from the Brazilian Registry of Bone Biopsy (REBRABO) has pointed out a high incidence of aluminum (Al) accumulation in the bones of patients with CKD under dialysis. This surprising finding does not appear to be merely a passive metal accumulation, as prospective data from REBRABO suggest that the presence of Al in bone may be independently associated with major adverse cardiovascular events. This information contrasts with the perception of epidemiologic control of this condition around the world. In this opinion paper, we discussed why the diagnosis of Al accumulation in bone is not reported in other parts of the world. We also discuss a range of possibilities to understand why bone Al accumulation still occurs, not as a classical syndrome with systemic signs of intoxication, as occurred it has in the past.

Data-driven, two-stage machine learning algorithm-based prediction scheme for assessing 1-year and 3-year mortality risk in chronic hemodialysis patients

Life expectancy is likely to be substantially reduced in patients undergoing chronic hemodialysis (CHD). However, machine learning (ML) may predict the risk factors of mortality in patients with CHD by analyzing the serum laboratory data from regular dialysis routine. This study aimed to establish the mortality prediction model of CHD patients by adopting two-stage ML algorithm-based prediction scheme, combined with importance of risk factors identified by different ML methods. This is a retrospective, observational cohort study. We included 800 patients undergoing CHD between December 2006 and December 2012 in Shin-Kong Wu Ho-Su Memorial Hospital. This study analyzed laboratory data including 44 indicators. We used five ML methods, namely, logistic regression (LGR), decision tree (DT), random forest (RF), gradient boosting (GB), and eXtreme gradient boosting (XGB), to develop a two-stage ML algorithm-based prediction scheme and evaluate the important factors that predict CHD mortality. LGR served as a bench method. Regarding the validation and testing datasets from 1- and 3-year mortality prediction model, the RF had better accuracy and area-under-curve results among the five different ML methods. The stepwise RF model, which incorporates the most important factors of CHD mortality risk based on the average rank from DT, RF, GB, and XGB, exhibited superior predictive performance compared to LGR in predicting mortality among CHD patients over both 1-year and 3-year periods. We had developed a two-stage ML algorithm-based prediction scheme by implementing the stepwise RF that demonstrated satisfactory performance in predicting mortality in patients with CHD over 1- and 3-year periods. The findings of this study can offer valuable information to nephrologists, enhancing patient-centered decision-making and increasing awareness about risky laboratory data, particularly for patients with a high short-term mortality risk.

Risk factors of left ventricular diastolic dysfunction in maintenance hemodialysis patients

OBJECTIVE

To investigate the risk factors of left ventricular diastolic dysfunction in maintenance hemodialysis (MHD) patients.

METHOD

We retrospectively collected data from 363 hemodialysis patients who were on dialysis for at least 3 months at January 1, 2020. According to the echocardiogram results, these patients were divided into left ventricular diastolic dysfunction (LVDD) group and non-LVDD group. The differences in basic data, cardiac structure and functiona between the two groups were analyzed. Logistic regression analysis was used to analyze the risk factors of cardiac diastolic dysfunction in MHD patients.

RESULTS

Compared with the non-LVDD group, patients in the LVDD group were older, with an increased proportion of coronary heart disease, more prone to chest tightness, shortness of breath. Simultaneously, they had a significantly increased (p < 0.05) proportion of cardiac structural abnormalities such as left ventricular hypertrophy, left heart enlargement and systolic dysfunction. Multivariate logistic regression analysis showed that the risk of LVDD was significantly increased in elderly MHD patients older than 60 years (OR = 3.86, 95%CI 1.429-10.429), and left ventricular hypertrophy was also significantly associated with LVDD (OR = 2.227, 95% CI 1.383-3.586).

CONCLUSION

According to research, both age and left ventricular hypertrophy are risk factors for LVDD in MHD patients. It is recommended that early intervention for LVDD should be implemented to improve the quality of dialysis and reduce the incidence of cardiovascular events in MHD patients.

Blood Aluminum Levels in Patients with Hemodialysis and Peritoneal Dialysis

Background. This retrospective observational study attempted to examine the prevalence of abnormal blood aluminum levels in dialysis patients, and to explore the association of pathogenic factors, such as demographic, clinical, laboratory as well as the use of phosphate binding drugs, drugs for secondary hyperparathyroidism and erythropoiesis-stimulating drugs with the blood aluminum levels. Methods. The study included 1175 patients (874 hemodialysis and 301 peritoneal dialysis), recruited from Chang Gung Memorial Hospital in November 2020. Patients were stratified into two groups by their blood aluminum levels, as normal (<2 µg/dL, n = 1150) or abnormal (≥2 µg/dL, n = 25). Results. The patients aged 60.4 ± 13.2 years and were dialyzed for 8.6 ± 8.1 years. The average blood aluminum level was 1.0 ± 0.4 µg/dL. Patients with abnormal blood aluminum levels received more sevelamer than patients with normal blood aluminum level (p = 0.014). Patients with abnormal blood aluminum levels had higher platelet count (p = 0.001), triglyceride (p < 0.001) and total iron binding capacity (p = 0.003) than patients with normal blood aluminum levels. Moreover, the cardiothoracic ratio was higher in patients with abnormal blood aluminum levels than patients with normal blood aluminum levels (p = 0.003). Conclusions. The prevalence of abnormal blood aluminum levels was low at 2.2%. Nevertheless, the linking of cardiothoracic ratio of more than 0.5 as well as elevated blood platelet count and triglyceride level with blood aluminum levels are interesting, and warranted more researches in this area.

Association Between Serum Aluminum Level and Uremic Pruritus in Hemodialysis Patients

Uremic pruritus (UP) is a common symptom in patients undergoing hemodialysis (HD). The pathogenesis of UP is complex. Aluminum (Al) is a common metal and is toxic to patients undergoing HD. Al is also a known human allergen which can induce immune reactions. However, the correlation between Al and UP remains unclear in dialysis patients. A total of 866 patients on maintenance HD were enrolled for analysis. The HD patients with higher serum Al levels had higher a prevalence of UP than those with lower serum Al levels. After adjusting for confounding variables, the serum Al level was significantly associated with UP. Overall, each 10-fold increase in serum Al level was associated with a 5.64-fold increase in the risk of developing UP in these subjects. The results of this cross-sectional study suggest that serum Al level may be associated with the development of UP in patients on maintenance HD.

Association of Serum Aluminum Levels with Mortality in Patients on Chronic Hemodialysis

Despite reported evidence on the relationship between higher serum aluminum levels and poor outcomes in patients on chronic hemodialysis (CHD), the acceptable cutoff value of serum aluminum for mortality remains unclear. A retrospective observational cohort study with 636 Taiwanese patients on CHD was conducted to investigate the impact of serum aluminum levels on mortality. The predictors were bivariate serum aluminum level (<6 and ≥6 ng/mL) and the Outcomes were all-cause and cardiovascular (CV) mortality. During the mean follow-up of 5.3 ± 2.9 years, 253 all-cause and 173 CV deaths occurred. Crude analysis showed that a serum aluminum level of ≥6 ng/mL was a significant predictor of all-cause [hazard ratio (HR), 1.80; 95% confidence interval (CI), 1.40–2.23] and CV (HR, 1.84; 95% CI, 1.36–2.50) mortality. After multivariable adjustment, the serum aluminum level of ≥6 ng/mL remained a significant predictor of all-cause mortality (HR, 1.37, 95% CI, 1.05–1.81) but became insignificant for CV mortality (HR, 1.29; 95% CI, 0.92–1.81). Therefore, our study revealed that a serum aluminum level of ≥6 ng/mL was independently associated with all-cause death in patients on CHD, suggesting that early intervention for aluminum level in patients on CHD might be beneficial even in the absence of overt aluminum toxicity.

Aluminum exposure for 60days at an equivalent human dietary level promotes peripheral dysfunction in rats

Aluminum (Al) is a neurotoxic associated with a number of chronic human diseases. We investigated the effects of Al exposure at doses similar to human dietary levels and at a high level exposure to Al on the peripheral nervous system. Wistar male rats were divided into two major groups and received orally: 1) First group - Low level - rats were subdivided and treated for 60days: a) Control - received ultrapure water; b) AlCl₃ - received Al at 8.3mg/kg body weight (bw) for 60days; and 2) Second group - High level - rats were subdivided and treated for 42days: C) Control - received ultrapure water through oral gavage; d) AlCl₃ - received Al at 100mg/kg bw for 42days. Von Frey hair test, plantar test, the presence of catalepsy and the spontaneous motor activity were investigated. Reactive oxygen species, lipid peroxidation and total antioxidant capacity, immunohistochemistry to investigate the nerve inflammation and, the specific presence of Al in the sciatic nerve fibers were investigated. Al exposure at a representative human dietary level promotes the development of mechanical allodynia, catalepsy, increased inflammation in the sciatic nerve, systemic oxidative stress and, is able to be retained in the sciatic nerve. The effects of low-dose Al were similar to those found in rats exposed to Al at a dose much higher (100mg/kg). Our findings suggest that Al may be considered toxic for the peripheral nervous system, thus inducing peripheral dysfunction.