Associations of time-dependent changes in phosphorus levels with cardiovascular diseases in patients undergoing hemodialysis: results from the Japan Dialysis Active Vitamin D (J-DAVID) randomized clinical trial.

Background: While the risk of exceeding the standard range of phosphorus levels has been investigated, the impact of the degree of fluctuations has not been investigated. Methods: Data were derived from the Japan Dialysis Active Vitamin D trial, a 4-year prospective, randomized study involving 976 patients without secondary hyperparathyroidism undergoing hemodialysis in Japan. Laboratory data were collected every 6 months and the primary outcome was the time to the occurrence of cardiovascular events. The effect of time-dependent changes in phosphorus levels was assessed using a time-varying Cox proportional hazards regression model. Results: The median serum phosphorus levels at baseline and at the final observation were 4.70 mg/dl [interquartile range (IQR) 3.90-5.30] and 5.00 mg/dl (IQR 4.20-5.80), respectively. Over each 6-month period, phosphorus changes ranged from -7.1 to +6.7 mg/dl, with a median value of -0.1 to +0.3 mg/dl. During follow-up, composite cardiovascular events occurred in 103 of 964 patients. Although the P-value for the interaction between serum phosphorus level fluctuations and baseline phosphorus levels was insignificant, the following trends were observed. First, patients with relatively high initial phosphorus levels over a 6-month period showed a trend towards a higher hazard, with greater changes in the phosphorus level over the 6-month period. Second, it was suggested that oral vitamin D receptor activators could contribute to the relationship between fluctuating phosphorus levels and cardiovascular events. Conclusions: Our results suggest the importance of maintaining stable phosphorus levels, not only in the normal range, but also without fluctuations, in the risk of cardiovascular events among patients without secondary hyperparathyroidism undergoing maintenance hemodialysis.

Relationship between selection of dosage forms of vitamin D receptor activators and short-term survival of patients on hemodialysis.

BACKGROUND: The benefits of vitamin D receptor activators (VDRAs) for patients with chronic kidney disease are well recognized. However, the optimal criteria for patient selection, dosage forms, and duration providing the highest benefit and the least potential risk remain to be confirmed. MATERIALS AND METHODS: The study population was derived from the Aichi Cohort Study of Prognosis in Patients Newly Initiated into Dialysis, a multicenter prospective cohort study of 1520 incident dialysis patients. According to the VDRA usage status in March 2015 (interim report), the 967 patients surviving after March 2015 were classified into three groups: without VDRA (NV, n = 177), oral VDRA (OV, n = 447), and intravenous VDRA (IV, n = 343). Mortality rates were compared using the log-rank test, and factors contributing to all-cause mortality were examined using both univariate and multivariate Cox proportional hazard regression analyses. RESULTS: There were 104 deaths (NV, n = 27; OV, n = 53; IV, n = 24) during the follow-up period (1360 days, median), and significant differences in cumulative survival rates were observed between the three groups (p = 0.010). Moreover, lower all-cause mortality was associated with IV versus NV (hazard ratio, 0.46 [95% confidence interval 0.24-0.89]; p = 0.020). CONCLUSION: This study demonstrated the impact of the VDRA dosage form on the short-term survival of incident hemodialysis patients during the introduction period. Our results suggest that relatively early initiation of intravenous VDRA in patients beginning hemodialysis may have some clinical potential.

Extreme hyperuricemia is a risk factor for infection-related deaths in incident dialysis patients: a multicenter prospective cohort study.

INTRODUCTION: There are few studies on the association between serum uric acid (UA) level and mortality in incident dialysis patients. We aimed to clarify whether the serum UA level at dialysis initiation is associated with mortality during maintenance dialysis. METHODS: We enrolled 1486 incident dialysis patients who participated in a previous multicenter prospective cohort study in Japan. We classified the patients into the following five groups according to their serum UA levels at dialysis initiation: G1 with a serum UA level <6 mg/dL; G2, 6.0-8.0 mg/dL; G3, 8.0-10.0 mg/dL; G4, 10.0-12.0 mg/dL; and G5, ≥12.0 mg/dL. We created three models (Model 1: adjusted for age and sex, Model 2: adjusted for Model 1 + 12 variables, and Model 3: stepwise regression adjusted for Model 2 + 13 variables) and performed a multivariate Cox proportional hazard regression analysis to examine the association between the serum UA level and outcomes, including infection-related mortality. RESULTS: Hazard ratios (HRs) were calculated relative to the G2, because the all-cause mortality rate was the lowest in G2. For Models 1 and 2, the all-cause mortality rate was significantly higher in G5 than in G2 (HR: 1.63, 95% confidence interval [CI]: 1.14-2.33 and HR: 1.78, 95% CI: 1.19-2.68, respectively). For Models 1, 2, and 3, the infection-related mortality rate was significantly higher in G5 than in G2 (HR: 2.75, 95% CI: 1.37-5.54, HR: 3.09, 95% CI: 1.45-6.59, HR: 3.37, and 95% CI: 1.24-9.15, respectively). CONCLUSIONS: Extreme hyperuricemia (serum UA level ≥12.0 mg/dL) at dialysis initiation is a risk factor for infection-related deaths.

Prediction model for cardiovascular events or all-cause mortality in incident dialysis patients.

Some variables including age, comorbidity of diabetes, and so on at dialysis initiation are associated with patient prognosis. Cardiovascular (CV) events are a major cause of death, and adequate models that predict prognosis in dialysis patients are warranted. Therefore, we created models using some variables at dialysis initiation. We used a database of 1,520 consecutive dialysis patients (median age, 70 years; 492 women [32.4%]) from a multicenter prospective cohort study. We established the primary endpoint as a composite of the incidence of first CV events or all-cause death. A multivariable Cox proportional hazard regression model was used to construct a model. We considered a complex and a simple model. We used area under the receiver operating characteristic curve (AUROC) to assess and compare the predictive performances of the prediction models and evaluated the improvement in discrimination using the complex model versus the simple model using net reclassification improvement (NRI). We then assessed integrated discrimination improvement (IDI) to evaluate improvements in average sensitivity and specificity. Of 392 deaths, 152 were CV-related. Totally, 506 CV events occurred during the follow-up period (median 1,285 days). Finally, 692 patients reached the primary endpoint. Baseline data were set at dialysis initiation. AUROC for the primary endpoint was 0.737 (95% confidence interval [CI], 0.712-0.761) in the simple model and 0.765 (95% CI, 0.741-0.788) in the complex model. There were significant intergroup differences in NRI (0.44; 95% CI, 0.34-0.53; p < 0.001) and IDI (0.02; 95% CI, 0.02-0.03; p < 0.001). We prepared a Shiny R application for each model to automatically calculate the predicted occurrence probability (https://statacademy.shinyapps.io/App_inaguma_20190717/). The complex model made more accurate predictions than the simple model. However, the intergroup difference was not significant. Hence, the simple model was more useful than the complex model. The tool was useful in a real-world clinical setting because it required only routinely available variables. Moreover, we emphasized that the tool could predict the incidence of CV events or all-cause mortality for individual patients. In the future, we must confirm its external validity in other prospective cohorts.

Oral ferrous citrate or ferrous sulfate use during predialysis may reduce serum phosphate level at dialysis initiation
.

AIM: Some reports claim that intravenous iron supplements reduce serum phosphate levels in patients with chronic kidney disease (CKD), including those on dialysis. However, whether divalent oral iron supplements influence serum phosphate levels in patients with CKD remains unclear; thus, this study aimed to address this topic. MATERIALS AND METHODS: The study database was derived from the Aichi Cohort Study of Prognosis in Patients Newly Initiated into Dialysis (AICOPP), which is a multicenter, prospective, cohort study. Patients were classified into two groups: those who received iron orally (iron group, n = 255) from pre-dialysis to dialysis initiation and those who did not receive iron supplements (no-iron group, n = 1,261). Moreover, patients were classified into two groups (255 patients in each) by propensity score (PS) matching. We compared serum phosphate level at dialysis initiation and all-cause mortality. Multivariate regression analysis was used to extract factors contributing to serum phosphate level at dialysis initiation through a stepwise method. RESULTS: Serum phosphate levels at dialysis initiation were significantly lower in the iron group (all cohort, 6.0 ± 1.6 vs. 6.4 ± 1.9 mg/dL, p = 0.001; PS-matched cohort, 6.0 ± 1.6 vs. 6.5 ± 1.7 mg/dL, p = 0.001). Multivariate regression analysis revealed that oral iron supplementation was significantly correlated to serum phosphate level (p = 0.023). There were no significant differences in all-cause mortality after dialysis initiation. CONCLUSION: This study showed that oral ferrous citrate or ferrous sulfate use during predialysis was associated with differences in serum phosphate level at dialysis initiation.

Relationship between History of Ischemic Stroke and All-Cause Mortality in Incident Dialysis Patients.

BACKGROUND: Few studies have focused on the association between history of ischemic stroke at predialysis stage and mortality after dialysis initiation. OBJECTIVE: To examine whether history of stroke in incident dialysis patients is associated with mortality, including all-cause and cardiovascular (CV)-related mortality. METHODS: The study database was derived from the Aichi Cohort Study of Prognosis in Patients Newly Initiated into Dialysis, a multicenter, prospective, cohort analysis. We classified patients into 2 groups according to their history of ischemic stroke and compared their outcomes. Propensity scores (PSs) represented the probability of being assigned to a group with or without a history of ischemic stroke. We defined the following outcomes: all-cause mortality; CV-related mortality; non-CV-related mortality; infection-related mortality; and stroke event after dialysis initiation. Factors contributing to the outcomes were examined using stepwise multivariate Cox proportional hazards analysis. RESULTS: All-cause mortality was significantly higher in the ischemic stroke group (log-rank test p < 0.001). All-cause, non-CV-related, and infection-related mortality and stroke event after dialysis initiation were significantly higher in the ischemic stroke group after PS matching (log-rank test: p < 0.001, <0.001, 0.002, and 0.002, respectively). History of ischemic stroke was associated with all-cause mortality in univariate analysis (hazard ratio [HR] 1.85, 95% CI 1.44-2.37). History of ischemic stroke before dialysis initiation was associated with all-cause mortality in multivariate analysis (HR 1.39, 95% CI 1.05-1.85). CONCLUSION: The present study revealed that history of ischemic stroke before dialysis initiation was associated with all-cause, non-CV-related, and infection-related mortality and stroke event after dialysis initiation during maintenance dialysis.

Effect of Low-Density Lipoprotein Apheresis for Nephrotic Idiopathic Membranous Nephropathy as Initial Induction Therapy.

Low-density lipoprotein apheresis (LDL-A) has been used for nephrotic syndrome (NS) caused by focal segmental glomerulosclerosis in Japan. Idiopathic membranous nephropathy (iMN) can also cause treatment-resistant NS. Therefore, we investigated the effect of LDL-A during initial induction for it. This retrospective, observational, and single-center study enrolled consecutive iMN patients who received steroids from March 2000 to May 2015. We compared data between 11 patients treated with LDL-A (LDL-A group) and 27 patients without (non-LDL-A group) at baseline and 4 and 8 weeks later. Reduction rate of proteinuria and increase rate of serum albumin in LDL-A group were significantly higher than the other after 4 weeks (P = 0.036 and 0.030) and 8 weeks (P = 0.030 and <0.001), respectively. There was no adverse event caused by LDL-A and immunosuppressant dose was not significantly different. In conclusion, LDL-A may be an effective choice for initial induction of nephrotic iMN.