Cardiovascular Events and Mortality in Patients on Hemodialysis: The Prognostic Value of the CHA2DS2-VASc Score.

Background and Objectives: Cardiovascular events are the major cause of morbidity and mortality in patients on hemodialysis (HD). Identifying risk factors can help in the effort to reduce cardiovascular risk and improve life expectancy. The objective of this study was to evaluate the ability of the CHA2DS2-VASc score-the risk index of stroke in atrial fibrillation (AF)-to predict strokes, major cardiovascular events, and mortality in patients with end-stage kidney disease. Materials and Methods: The CHA2DS2-VASc and HAS-BLED scores (the bleeding risk from the use of anticoagulation in AF) were calculated in 237 HD patients, 99 women with a median age of 76 (15) years, at the time they commenced HD. The scores' ability to predict long term cardiovascular morbidity and mortality was estimated, both in those with and without AF. Among the exclusion criteria were the change of dialysis method or loss of follow-up, HD due to acute renal failure, and incompliance with medical instructions, thus the sample is not representative of a broader population. Results: The CHA2DS2-VASc score was higher in AF (n = 69) compared to non-AF (n = 168) patients, 5 (2.5) vs. 4 (2), p < 0.0001, respectively. An increased CHA2DS2-VASc score was correlated with cardiovascular events, namely, heart failure (p = 0.007, p = 0.024), stroke (p < 0.0001, p < 0.0001), and risk of all-cause mortality (p < 0.0001, p < 0.0001) in AF and non-AF groups, respectively. The C statistics indicated that the referred score showed modest discrimination in AF and non-AF patients on HD for heart failure, stroke, and all-cause mortality, however for cardiovascular mortality this was found only in the AF group. Conclusions: An increased CHA2DS2-VASc score at the time of HD initiation can predict strokes, heart failure, and all-cause mortality in HD patients independent of the presence of AF. The risk of cardiovascular mortality could only be predicted in patients with AF.

Immunosenescence and Immune Exhaustion Are Associated with Levels of Protein-Bound Uremic Toxins in Patients on Hemodialysis.

BACKGROUND: The accumulation of protein-bound uremic toxins (PBUTs) in chronic kidney disease may affect patients' immune status. The aim of the study was to evaluate their potential impacts on lymphocyte alterations in patients on hemodialysis (HD). METHODS: The plasma levels of PBUTs were assessed in 54 patients on HD and 31 healthy individuals, using ultra-performance liquid chromatography. The results correlated with the senescent and exhausted status of lymphocytes, based on certain surface molecules, analyzed by flow cytometry. RESULTS: The plasma levels of PBUTs were significantly increased in the patients on HD compared with the healthy controls. The patients with residual kidney function had reduced hippuric acid (HA) levels, total (p = 0.03) and free (p = 0.04), and free IxS levels (p = 0.02). The total and free HA levels correlated negatively with less differentiated subpopulations, CD4+CD45RA+CD31+ (p = 0.037 and p = 0.027), CD8+CD28+CD57- (p = 0.01, p = 0.01), and naïve B cells (CD19+IgD+CD27-) (p = 0.04, p = 0.03). Both the total and the free pCS levels correlated positively with exhausted CD4 cells, p = 0.02 and p = 0.01, respectively. A multivariate analysis showed that IxS and age were the main independent parameters implicated in the reduction intotal CD4 and B lymphocytes and their naïve and early differentiated subsets. CONCLUSIONS: Increased PBUTs levels are associated with immune disturbances of patients on HD, HA, and IxS in the immunosenescent and pCS in the immunoexhaustion alterations.

The prognostic value of CHA2 DS2 -VASc and modified-CHADS2 scores for cardiovascular events in diabetics and non-diabetics haemodialysis patients.

AIM: CHA2 DS2 -VASc and modified-CHADS2 score can easily estimate the risk of stroke in atrial fibrillation. Study's purpose was to evaluate these in haemodialysis patients, and assess the effect of diabetes mellitus (DM). METHODS: The scores calculated in 237 haemodialysis patients, 121 diabetics (58 females) and 116 non-diabetics (41 females). Results correlated to cardiovascular events (acute myocardial infarction, atrial fibrillation, heart failure, peripheral arterial disease, stroke, mortality). RESULTS: CHA2 DS2 -VASc score correlated with the occurrence of stroke and heart failure (p < .01, p < .01), (p < .01, p < .01), respectively in diabetics and non-diabetics. CHA2 DS2 -VASc score could predict the risk of all-cause mortality in both groups, p = .03, p < .01, respectively, however, the risk of cardiovascular death could be predicted in non-diabetics, p < .01. Modified-CHADS2 score associated with heart failure (p = .04), cardiovascular (p < .01) and all-cause mortality (p < .01) only on non-diabetics. C statistics indicated that the first score showed modest discrimination in patients with and without DM, for stroke and all-cause mortality. The second score performed modestly only on patients without DM for all-cause mortality. Both scores showed poor calibration. Stroke was a common cause of cardiovascular death (OR = 3.52, 95% CI = 1.92-6.47, p < .01) and associated with central venous catheter (OR = 2.19, 95% CI = 1.12-4.27, p = .02) and pre-existing atrial fibrillation (OR = 1.94, 95% CI = 1.06-3.58, p = .03). CONCLUSION: CHA2 DS2 -VASc score correlated with stroke, heart failure and all-cause mortality in haemodialysis patients with and without DM. The risk of cardiovascular death could be predicted only in non-diabetics patients. Modified-CHADS2 score correlated with heart failure, cardiovascular and all-cause mortality only on non-diabetics. Both had modest discrimination and poor calibration.

Microbiome in Chronic Kidney Disease.

The gut microbiome is a complex collection of microorganisms with discrete characteristics and activities. Its important role is not restricted to food digestion and metabolism, but extends to the evolution, activation and function of the immune system. Several factors, such as mode of birth, diet, medication, ageing and chronic inflammation, can modify the intestinal microbiota. Chronic kidney disease (CKD) seems to have a direct and unique effect, as increased urea levels result in alteration of the gut microbiome, leading to overproduction of its metabolites. Therefore, potentially noxious microbial uremic toxins, which have predominantly renal clearance, including p-cresyl sulfate, indoxyl sulfate and N-oxide of trimethylamine [Trimethylamine-N-Oxide (TMAO)], accumulate in human's body, and are responsible not only for the clinical implications of CKD, but also for the progression of renal failure itself. Certain changes in gut microbiome are observed in patients with end stage renal disease (ESRD), either when undergoing hemodialysis or after kidney transplantation. The purpose of this review is to summarize the changes of gut microbiome and the protein bound uremic toxins which are observed in CKD and in different kidney replacement strategies. In addition, we attempt to review the connection between microbiome, clinical implications and immune response in CKD.