Impact of nutritional index on the association between phosphorus concentrations and mortality in haemodialysis patients: a cohort study from dialysis outcomes and practice pattern study in Japan

Importance of dialysis specialists in early mortality in elderly hemodialysis patients: a multicenter retrospective cohort study

The early mortality rate in elderly patients undergoing hemodialysis is more than twice that in young patients, requiring more specialized healthcare. We investigated whether the number of professional dialysis specialists affected early mortality in elderly patients undergoing hemodialysis. This multicenter retrospective cohort study analyzed data from 1860 patients aged ≥ 70 years who started hemodialysis between January 2010 and December 2017. Study regions included Seoul, Gyeonggi-do, Gangwon-do, Daejeon/Chungcheong-do, Daegu/Gyeongsangbuk-do, and Busan/Ulsan/Gyeongsangnam-do. The number of patients undergoing hemodialysis per dialysis specialist was calculated using registered data from each hemodialysis center. Early mortality was defined as death within 6 months of hemodialysis initiation. Gangwon-do (28.3%) and Seoul (14.5%) showed the highest and lowest early mortality rate, respectively. Similarly, Gangwon-do (64.6) and Seoul (43.9) had the highest and lowest number of patients per dialysis specialist, respectively. Relatively consistent results were observed for the regional rankings of early mortality rate and number of patients per dialysis specialist. Multivariate Cox regression analysis-adjusted for previously known significant risk factors-revealed that the number of patients per dialysis specialist was an independent risk factor for early mortality (hazard ratio: 1.031, p < 0.001). This study underscores the growing need for dialysis specialists for elderly hemodialysis patients in Korea.

Reduced phosphorus is associated with older age and hypoalbuminemia. Risk factors for all-cause mortality in peritoneal dialysis patients

Introduction/aim

Hyperphosphatemia is a mortality risk factor in dialysis patients; however, low phosphorus levels too. Diabetes and malnutrition are strongly associated with mortality and with reduced serum phosphorus. This study analyzed the pattern of serum phosphorus in patients on Peritoneal Dialysis (PD) and its association with mortality.

Methods

A Secondary analysis was performed on a multicenter cohort study in peritoneal dialysis patients from two previous studies done by our group.

Results

Six hundred fifty-four patients were included. Serum phosphorus was <3.6 mg/dL in 28.29% of patients, 3.6 to 5.2 mg/dL in 48.16%, and >5.2 mg/dL in 23.55%. In logistic regression analysis; education, age, and hypoalbuminemia were risk factors for low P levels. In multivariate Cox analysis P < 3.6 mg/dL, age, and low albumin were predictors for all-cause mortality. When lower P and lower albumin were combined, this group had the highest risk for all cause and cardiovascular mortality.

Conclusion

The frequency of patients with reduced serum phosphorus was higher in the Mexican population than in Europe or Asia. Low serum phosphorus levels, older age and hypoalbuminemia were risk factors for all-cause mortality. Low phosphorus combined with low albumin levels were the highest risk factor for all-cause and cardiovascular mortality.

Emerging cross-talks between chronic kidney disease-mineral and bone disorder (CKD-MBD) and malnutrition-inflammation complex syndrome (MICS) in patients receiving dialysis

Chronic kidney disease–mineral and bone disorder (CKD–MBD) is a systemic disorder that affects multiple organs and systems and increases the risk of morbidity and mortality in patients with CKD, especially those receiving dialysis therapy. CKD–MBD is highly prevalent in CKD patients, and its treatment is gaining attention from healthcare providers who manage these patients. Additional important pathologies often observed in CKD patients are chronic inflammation and malnutrition/protein-energy wasting (PEW). These two pathologies coexist to form a vicious cycle that accelerates the progression of various other pathologies in CKD patients. This concept is integrated into the term “malnutrition–inflammation–atherosclerosis syndrome” or “malnutrition–inflammation complex syndrome (MICS)”. Recent basic and clinical studies have shown that CKD–MBD directly induces inflammation as well as malnutrition/PEW. Indeed, higher circulating levels of inorganic phosphate, fibroblast growth factor 23, parathyroid hormone, and calciprotein particles, as markers for critical components and effectors of CKD–MBD, were shown to directly induce inflammatory responses, thereby leading to malnutrition/PEW, cardiovascular diseases, and clinically relevant complications. In this short review, we discuss the close interplay between CKD–MBD and MICS and emphasize the significance of simultaneous control of these two seemingly distinct pathologies in patients with CKD, especially those receiving dialysis therapy, for better management of the CKD/hemodialysis population.

Relationship between malnutrition and possible sarcopenia in the AWGS 2019 consensus affecting mortality in hemodialysis patients: a prospective cohort study

Background

The first objective of this study was to determine the relationship between muscle strength or physical performance and mortality, and the second objective was to show the relationship of Geriatric Nutritional Risk Index (GNRI) to muscle strength and physical performance decline.

Methods

We examined handgrip, the 5-times chair stand test, and GNRI in 635 maintenance hemodialysis patients and followed up for 72 months. Predictors for all-cause death were examined using Kaplan-Meier analysis and Cox proportional analysis. The relationship between possible sarcopenia and nutritional disorder (GNRI) was constructed receiver operating characteristic (ROC) curve. We used the Youden index to determine the optimal cutoff points for GNRI.

Results

The multivariate Cox proportional hazard analysis revealed that the GNRI did not show any significance, although handgrip (HR 3.61, 95% CI 1.70–7.68, p < 0.001) and the 5-times chair stand test (HR 1.71 95% CI 1.01–2.90, p = 0.045) were significant predictors for mortality. On the evaluation of possible sarcopenia by handgrip strength, the area under curve (AUC) on ROC curve analysis were 0.68 (95% CI 0.64–0.72), and 5-chair stand, the AUC on ROC were 0.55 (95% CI 0.51–0.60). The cut-off value for the GNRI discriminating those at possible sarcopenia by handgrip strength based on the Youden index was 91.5.

Conclusions

Our study suggests that the handgrip strength test of the AWGS 2019 sarcopenia consensus was a simple and useful tool to predict mortality in chronic hemodialysis patients. Furthermore, GNRI assessment can be a useful tool for screening before assessing possible sarcopenia when it is difficult to perform SARC-F to all patients.

Medical Director Practice of Advising Increased Dietary Protein Intake in Hemodialysis Patients With Hyperphosphatemia: Associations With Mortality in the Dialysis Outcomes and Practice Patterns Study

OBJECTIVES

Patients undergoing hemodialysis (HD) may have poor nutritional status and hyperphosphatemia. Nephrologists sometimes manage hyperphosphatemia by prescribing phosphate binders and/or recommending restriction of dietary phosphate including protein-rich foods; the later may, however, adversely affect nutritional status.

DESIGN AND METHODS

The analysis includes 8805 HD patients on dialysis ≥ 120 days in 12 countries in Dialysis Outcomes and Practice Patterns Study (DOPPS) phase 4 (2009-2011), from 248 facilities. The primary exposure variable was response to the following question: "For patients with serum albumin 3.0 g/dL and phosphate 6.0 mg/dL, do you recommend to (A) increase or (B) decrease/no change in dietary protein intake (DPI)?". The association between medical director's practice of recommending an increase in DPI and all-cause mortality was analyzed with Cox regression adjusted for potential confounders. Linear and logistic regressions were used to model the cross-sectional associations between DPI advice practice and intermediate markers of patient nutrition.

RESULTS

Median follow-up was 1.6 years. In the case scenario, 91% of medical directors in North America had a practice of recommending DPI increase compared to 58% in Europe (range = 36%-83% across 7 countries) and 56% in Japan. The practice of advising DPI increase was weakly associated with lower mortality [HR (95% CI): 0.88 (0.76-1.02)]. The association tended to be stronger in patients with age 70+ years [HR (95% CI): 0.82 (0.69-0.97), P = .12 for interaction]. The practice of advising DPI increase was associated with 0.276 mg/dL higher serum creatinine levels (95% CI: 0.033-0.520) after adjustment for case mix.

CONCLUSIONS

Medical director's practice of recommending an increase in DPI for HD patients with low albumin and high phosphate levels was associated with higher serum creatinine levels and potentially lower all-cause mortality. To recommend protein intake liberalization in parallel with phosphate management by physicians may be a critical practice for better nutritional status and outcomes in HD patients.

Functional impairment attenuates the association between high serum phosphate and mortality in dialysis patients: a nationwide cohort study

BACKGROUND

Both functional impairment and abnormalities in mineral and bone disorder (MBD) parameters are well-known predictors of mortality in dialysis patients. However, previous studies have not evaluated whether functional impairment modifies the association between MBD parameters and mortality.

METHODS

A nationwide prospective cohort study was conducted using data from the Japanese Society for Dialysis Therapy Renal Data Registry collected at the end of 2009 and 2010. The Eastern Cooperative Oncology Group performance status (PS) was used to assess functional status. Cox proportional hazards models were used to assess the associations of baseline functional status, serum phosphate, albumin-corrected calcium and intact parathyroid hormone (PTH) with 1-year all-cause mortality.

RESULTS

By 31 December 2010, 18 447 of 220 054 prevalent dialysis patients (8.4%) had died. Mortality significantly increased with worsening PS grade. PS grade modified the association of serum phosphate levels with mortality (Pinteraction = 0.001). Worsening PS grade attenuated the association of hyperphosphatemia (≥7.4 mg/dL) with mortality, and hyperphosphatemia was no longer significant on mortality among patients with the worst PS grade (hazard ratio = 1.1, 95% confidence interval 0.88-1.39), compared with the level between 3.5 and 4.7 mg/dL. In contrast, hypophosphatemia (<3.5 mg/dL) had a greater adjusted risk of mortality irrespective of PS grade. Serum-corrected calcium (Pinteraction = 0.26) and intact PTH (Pinteraction = 0.17) showed consistent associations with mortality irrespective of PS grade. Findings were robust in several sensitivity analyses.

CONCLUSIONS

Functional impairment was significantly associated with 1-year mortality and attenuated the effect of hyperphosphatemia on mortality among prevalent dialysis patients.

Geriatric nutrition risk index is associated with renal progression, cardiovascular events and all-cause mortality in chronic kidney disease

BACKGROUND

Malnutrition is common and associated with poor outcomes in patients with chronic kidney disease (CKD) and end-stage renal disease (ESRD). Recently, the geriatric nutritional risk index (GNRI) was reported as a novel tool for evaluating nutritional status. However, the association between GNRI and renal outcome, cardiovascular (CVD) events, and mortality in patients with CKD remains unclear.

METHODS

A prospective cohort study with adult patients with CKD stages 1-4 was conducted at 39 centers around China starting in 2011. Patients were divided into quartiles (Q1, Q2, Q3, and Q4) according to their GNRI category.

RESULTS

A total of 2791 CKD patients within a median follow-up of 4.38 years were included. A low GNRI quartile was independently associated with progression to ESRD, CVD events, and overall mortality. Compared to that in the Q1 group (the reference group), belonging to a higher GNRI quartile significantly reduced the risk of progression to ESRD in the crude and multivariate-adjusted models. Moreover, a significant inverse association was found between those in the high GNRI quartiles and overall mortality among patients with CKD (HR 0.25; 95% CI 0.15-0.43; p = 0.0007, Q4 vs. Q1) after multivariate adjustment. In addition, there was also a significant association between GNRI and CVD events (HR 0.57; 95% CI 0.39-0.84; p = 0.005, Q4 vs. Q1). Moreover, after adjusting for other confounders, only the Q3 group remained significantly fewer CVD events (HR 0.44; 95% CI 0.19-0.98; p = 0.04).

CONCLUSIONS

These findings suggest that GNRI might be a useful prognostic tool for patients with CKD.

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.

Association of serum mineral parameters with mortality in hemodialysis patients: Data from the Korean end-stage renal disease registry

BACKGROUND

We investigated the associations between mineral metabolism parameters and mortality to identify optimal targets in Korean hemodialysis patients.

METHODS

Among hemodialysis patients registered in the end-stage renal disease registry of the Korean Society of Nephrology between March 2012 and June 2017, those with serum calcium, phosphorus, and intact parathyroid hormone (iPTH) measured at enrollment were included. Association of serum levels of calcium, phosphorus, and iPTH with all-cause mortality was analyzed.

RESULTS

Among 21,433 enrolled patients, 3,135 (14.6%) died during 24.8 ± 14.5 months of follow-up. After multivariable adjustment, patients in the first quintile of corrected calcium were associated with lower mortality (hazard ratio [HR], 0.84; 95% confidence interval [95% CI], 0.71-0.99; P = 0.003), while those in the fifth quintile were associated with higher mortality (HR, 1.39; 95% CI, 1.20-1.61; P < 0.001) compared with those in the third quintile. For phosphorus, only the lowest quintile was significantly associated with increased mortality (HR, 1.24; 95% CI, 1.08-1.43; P = 0.003). The lowest (HR, 1.18; 95% CI, 1.02-1.36; P = 0.026) and highest quintiles of iPTH (HR, 1.24; 95% CI, 1.05-1.46; P = 0.013) were associated with increased mortality. For target counts achieved according to the Kidney Disease Outcomes Quality Initiative guideline, patients who did not achieve any mineral parameter targets hadhigher mortality than those who achieved all three targets (HR, 1.37; 95% CI, 1.12-1.67; P = 0.003).

CONCLUSION

In Korean hemodialysis patients, high serum calcium, low phosphorus, and high and low iPTH levels were associated with increased all-cause mortality.