Association between serum potassium levels and adverse outcomes in chronic kidney disease: the Fukushima CKD cohort study

Association between malnutrition and adverse renal outcomes in patients with type 2 diabetes

INTRODUCTION

Nutritional management is crucial in patients with chronic kidney disease. Therefore, it is important to assess nutritional status and detect malnutrition, especially in patients with diabetes. However, there is currently a lack of evidence regarding the relationship between nutritional indices and renal function in patients with type 2 diabetes. This study investigated whether the geriatric nutritional risk index (GNRI) is related to renal prognosis in type 2 diabetes patients.

MATERIALS AND METHODS

The study included 946 type 2 diabetes patients enrolled in the Fukushima Cohort Study. The primary endpoint of this study was a renal event, defined as a combination of a 50% decline in eGFR from baseline and end-stage kidney disease. All-cause death and new cardiovascular events were also measured as secondary outcomes. The association between GNRI and these endpoints was assessed using Cox regression analysis.

RESULTS

The median patient age was 66 years, 57% were men, the median eGFR was 67.9 mL/min/1.73 m2, and the median GNRI was 100.0. Compared to patients in the highest GNRI tertile, patients in the lowest tertile had a significantly increased risk of the renal event (HR 5.15, 95% CI 2.51-10.6) and all-cause death (HR 2.30, 95% CI 1.20-4.42). A significant association was not observed between GNRI levels and cardiovascular events.

CONCLUSIONS

We observed an association between poor nutritional status, assessed by GNRI, and adverse outcomes in patients with type 2 diabetes. Nutritional status assessment has potential utility as a prognostic tool for individuals with type 2 diabetes.

Hyperkalemia and Risk of CKD Progression: A Propensity Score-Matched Analysis

Key Points

Hyperkalemia is a known complication of CKD; however, it is not known whether hyperkalemia directly contributes to CKD progression and risk of death. We found that patients with stages 3b/4 CKD and hyperkalemia had higher risk of CKD progression and death than matched patients without hyperkalemia.

Background

Hyperkalemia is a known complication of CKD; however, it is not known whether hyperkalemia directly contributes to CKD progression and the risk of death. Clarifying the extent to which hyperkalemia is associated with CKD progression and mortality can inform clinical practice and guide future research. The objective of this study was to quantify the risks of CKD progression and mortality associated with hyperkalemia in patients with stages 3b/4 CKD.

Methods

This was a real-world, exact and propensity score matched, observational cohort study using data (January 2016 to December 2021) from Optum's deidentified Market Clarity Data, a large US integrated insurance claims/electronic medical record database. The study included matched adult patients with stages 3b/4 CKD with and without hyperkalemia, not regularly treated with an intestinal potassium (K+) binder. Measured outcomes were CKD progression and all-cause mortality. CKD progression was defined as diagnosis of CKD stage 4 (if stage 3b at index), CKD stage 5 or kidney failure, or receipt of dialysis or kidney transplantation.

Results

After matching, there were 6619 patients in each of the hyperkalemia and nonhyperkalemia cohorts, with a mean follow-up time of 2.12 (SD, 1.42) years. Use of any renin-angiotensin-aldosterone system inhibitors during baseline was common (75.9%), and most patients had CKD stage 3b (71.2%). Patients with hyperkalemia had a 1.60-fold (95% confidence interval, 1.50 to 1.71) higher risk of CKD progression and a 1.09-fold (1.02 to 1.16) higher risk of all-cause mortality relative to patients without hyperkalemia. Relative risks of CKD progression associated with hyperkalemia were similar within the subset of patients receiving renin-angiotensin-aldosterone system inhibitor, across CKD stages, and when alternative definitions of CKD progression were used.

Conclusions

Patients with CKD stages 3b/4 and hyperkalemia experienced significantly higher risks of CKD progression and all-cause mortality than propensity score matched patients without hyperkalemia.

Predictive values of four nutritional indices for adverse outcomes in patients with hypertension

BACKGROUND

Malnutrition, evaluated by nutritional indices, is reportedly related to a poor prognosis in patients with hypertension. However, clinical evidence on which index is more suitable for predicting a kidney prognosis is limited, and it has not been evaluated in hypertension. The aim of the present study was to investigate and compare the predictive values of four nutritional indices: Geriatric Nutritional Risk Index (GNRI); Prognostic Nutrition Index (PNI); Triglycerides × Total cholesterol × Body weight Index (TCBI); and the controlling nutritional status (CONUT) score.

METHODS

A retrospective, cohort study of 1255 hypertensive patients under care in the Fukushima Cohort Study was conducted. The primary outcome was kidney events, defined as a combination of a 50% decline in eGFR from baseline and renal failure requiring dialysis therapy or kidney transplantation. Kaplan-Meier analyses and multivariate Cox regression analyses were conducted to examine associations between the four nutritional indices and kidney events. The area under the curve (AUC) values of the receiver-operating characteristic curves were also examined to compare the predictive values of these nutritional indices.

RESULTS

Lower GNRI, lower PNI, and higher CONUT score were significantly related to a higher risk of kidney events. GNRI (AUC = 0.729, 95% confidence interval 0.681-0.777) and PNI (AUC = 0.710, 95% confidence interval 0.665-0.756) had significantly higher AUCs for kidney events than the TCBI and CONUT score.

CONCLUSIONS

GNRI and PNI showed greater predictive values for kidney events than other nutritional indices in patients with hypertension.

Geriatric Nutritional Risk Index is associated with adverse outcomes in patients with hypertension: the Fukushima Cohort study

Malnutrition is reportedly associated with adverse clinical outcomes in various populations. However, associations between nutritional status and adverse outcomes in patients with hypertension have not been sufficiently elucidated. We therefore aimed to investigate the impact of nutritional status as evaluated by the Geriatric Nutritional Risk Index (GNRI) on adverse outcomes in patients with hypertension. We conducted a retrospective cohort study of 1588 hypertensive patients enrolled in the Fukushima Cohort Study. Participants were categorized into tertiles (T1-T3) according to GNRI at baseline. The primary endpoint of the present study was a kidney event, defined as a combination of a 50% decline in eGFR from baseline and end-stage kidney disease requiring kidney replacement therapy. Associations between GNRI and kidney events were assessed using Kaplan-Meier curves and multivariate Cox regression analyses. Median age was 64 years, 55% were men, median eGFR was 63.1 mL/min/1.73 m2, and median GNRI was 101.3. The lower GNRI group (T1) showed an increased incidence of kidney events in the Kaplan-Meier curve analysis. Compared to the highest GNRI group (T3), lower GNRI carried a higher risk of kidney events for both T2 (hazard ratio [HR] 1.38, 95% confidence interval [CI] 0.71-2.68) and T1 (HR 3.59, 95%CI 1.96-6.63). Similar relationships were observed for risks of all-cause death and cardiovascular events. Lower GNRI was associated with kidney events, all-cause death, and cardiovascular events in patients with hypertension. Nutritional status as evaluated by GNRI could offer a simple and useful predictor of adverse outcomes in this population.

Elevated resting heart rate is associated with mortality in patients with chronic kidney disease

A higher heart rate is recognized as an independent risk factor for all-cause mortality and cardiovascular events in the general population. However, the association between elevated heart rate and clinical adverse outcomes in patients with non-dialysis-dependent chronic kidney disease (CKD) has not been sufficiently investigated. A total of 1353 participants enrolled in the Fukushima CKD Cohort Study were examined to investigate associations between resting heart rate and clinical adverse outcomes using Cox proportional hazards analysis. The primary outcome of the present study was all-cause mortality, with cardiovascular events as the secondary outcome. Participants were stratified into four groups based on resting heart rate levels at baseline (heart rate < 70/min, ≥ 70 and < 80/min, ≥ 80 and < 90/min, and ≥ 90/min). During the median observation period of 4.9 years, 123 participants died, and 163 cardiovascular events occurred. Compared with the reference level heart rate < 70/min group, the adjusted hazard ratios (HRs) for all-cause mortality were 1.74 (1.05-2.89) and 2.61 (1.59-4.29) for the heart rate ≥ 80 and < 90/min group and heart rate ≥ 90/min group, respectively. A significantly higher risk of cardiovascular events was observed in the heart rate ≥ 80/min and < 90/min group (adjusted HR 1.70, 1.10-2.62), but not in the heart rate ≥ 90/min group (adjusted HR 1.45, 0.90-2.34). In patients with non-dialysis-dependent CKD, a higher resting heart rate was associated with increased all-cause mortality.

Evaluating the associations between compliance with CKD guideline component metrics and renal outcomes

Understanding the association between compliance to the Chronic Kidney Disease (CKD) guidelines in real-world clinical settings and renal outcomes remains a critical gap in knowledge. A comprehensive analysis was conducted using data from a national, multicenter CKD registry. This study included 4,455 patients with an estimated glomerular filtration rate (eGFR) measurement on the index date and eight additional metrics recorded within six months. These metrics comprised serum electrolyte levels, low-density lipoprotein cholesterol, hemoglobin, and the use of renin-angiotensin system inhibitors. The primary outcome was a composite of renal events, defined by a decline in eGFR to < 15 mL/min/1.73 m2 or a reduction of ≥ 30% in eGFR, confirmed by follow-up tests. Over a median follow-up of 513 days, 838 renal events were observed. High serum potassium levels (> 5.4 mmol/L) were associated with increased event rates compared to lower levels. Similarly, low serum sodium-chloride levels (< 33) correlated with higher event rates. Usage of renin-angiotensin system inhibitors, low serum calcium (< 8.4 mg/dL), and high uric acid levels (> 7.0 mg/dL) were also linked to increased events. Conversely, higher hemoglobin levels (≥ 13 g/dL) were associated with lower event rates. Compliance to guidelines, categorized into quartiles based on the number of met metrics, revealed a significantly reduced risk of events in the highest compliance group (meeting 8 metrics) compared to the lowest (0-5 metrics). Compliance to CKD guidelines in clinical practice is significantly associated with improved renal outcomes, emphasizing the need for guideline-concordant care in the management of CKD.

Predicting CKD progression using time-series clustering and light gradient boosting machines

Predicting the transition of kidney function in chronic kidney disease is difficult as specific symptoms are lacking and often overlooked, and progress occurs due to complicating factors. In this study, we applied time-series cluster analysis and a light gradient boosting machine to predict the trajectories of kidney function in non-dialysis dependent chronic kidney disease patients with baseline estimated glomerular filtration rate (GFR) ≥ 45 mL/min/1.73 m2. Based on 5-year changes in estimated GFR, participants were stratified into groups with similar trajectories by cluster analysis. Next, we applied the light gradient boosting machine algorithm and Shapley addictive explanation to develop a prediction model for clusters and identify important parameters for prediction. Data from 780 participants were available for analysis. Participants were classified into five classes (Class 1: n = 78, mean [± standard deviation] estimated GFR 100 ± 19.3 mL/min/1.73 m2; Class 2: n = 176, 76.0 ± 9.3 mL/min/1.73 m2; Class 3: n = 191, 59.8 ± 5.9 mL/min/1.73 m2; Class 4: n = 261, 52.7 ± 4.6 mL/min/1.73 m2; and Class 5: n = 74, 53.5 ± 12.0 mL/min/1.73 m2). Declines in estimated GFR were 8.9% in Class 1, 12.2% in Class 2, 4.9% in Class 3, 12.0% in Class 4, and 45.1% in Class 5 during the 5-year period. The accuracy of prediction was 0.675, and the top three most important Shapley addictive explanation values were 1.61 for baseline estimated GFR, 0.12 for hemoglobin, and 0.11 for body mass index. The estimated GFR transition of patients with preserved chronic kidney disease mostly depended on baseline estimated GFR, and the borderline for estimated GFR trajectory was nearly 50 mL/min/1.73 m2.

Dietary intake, body composition and micronutrient profile of patients on maintenance hemodialysis attending Kiruddu National Referral Hospital, Uganda: A cross sectional study

Patients on maintenance hemodialysis are at a great risk for altered nutritional status, characterized by protein energy wasting and micronutrient deficiency due to medication interactions and dietary restrictions. This study determined the dietary intake, micronutrient profile and body composition of patients on maintenance hemodialysis at Kiruddu National referral hospital (KNRH), Uganda. A cross sectional study was done among adult CKD patients on maintenance hemodialysis therapy at KNRH. Data concerning patients' demographics, clinical history and dietary intake was obtained using interactive and quantitative food frequency questionnaires. Body composition was obtained using the TANITA BC-351, Japan weighing Bathroom scale and anthropometric measurements using standard methods and procedures. Serum micronutrient profile assessment was done using the COBAS Auto analyzer. Data analysis was done using the SPSS software version 20. T-test was used to make comparisons and logistic regression analysis was done to check for any correlations. A P-value of < 0.05 was considered statistically significant. Among the 63 hemodialysis patients, 38% were female, with a median duration of hemodialysis of 12 months and the overall age range of patients was 31-40 years. Majority (92.1%) of the patients had hypertension. Carbohydrates like maize flour were highly consumed, in addition to eggs among the proteins on the daily basis. Fruits and vegetables were not highly consumed. Regarding body composition; 75% of the study participants had normal Body mass Index (BMI), the mean muscle mass was 51.94±8.68, body fat was 15.25±7.35, bone mass was 2.77±0.46 and body water was 62.04±9.06. Patients had deranged micronutrient levels especially for Vitamin D, Potassium and phosphorus. In conclusion, hemodialysis patients at KNRH, have altered nutritional status as evidenced by altered body weight for some patients and deranged micronutrient levels. We recommend that hemodialysis patients should be regularly assessed for nutritional status, appropriately treated and educated about their nutritional status.

Coffee intake and risk of diabetic nephropathy: a Mendelian randomization study

Rationale and objective

A causal relationship concerning coffee intake and diabetic nephropathy (DN) is controversial. We conducted a Mendelian randomization study to assess the causal nature of these associations.

Methods

40 independent single nucleotide polymorphisms (SNPs) associated with coffee intake were selected from the UK Biobank study. Summary-level data for diabetic nephropathy were obtained from publicly available genome-wide association studies (GWAS) and the FinnGen consortium. Inverse variance weighted (IVW), MR-Egger, and weighted median (WM) methods were used to examine a causal association. Sensitivity analyses included Cochran's Q test, the intercept of MR-Egger, MR-PRESSO, and the Outlier method. Leave-One-Out sensitivity analyses were also conducted to reduce the heterogeneity.

Results

Our current study demonstrated positive associations of genetically predicted coffee intake with diabetic nephropathy (OR=1.939; P = 0.045 and type 2 diabetes with renal complications (OR = 2.787, P= 0.047). These findings were robust across several sensitivity analyses.

Conclusions

This study found a positive correlation between coffee consumption and the risk of diabetic nephropathy using genetic data. For a more accurate and trustworthy conclusion, subgroup analysis on coffee intake, including preparing method, variety of coffee, and quantity, is required.

Predialysis trajectories of estimated GFR and concurrent trends of Chronic Kidney Disease-relevant biomarkers

Background

The glomerular filtration rate (GFR) decline varies in patients with advanced chronic kidney disease (CKD), and the concurrent changes in CKD-related biomarkers are unclear.

Objectives

This study aimed to examine the changes in CKD-related biomarkers along with the kidney function decline in various GFR trajectory groups.

Design

This study was a longitudinal cohort study originated from the pre-end-stage renal disease (pre-ESRD) care program in a single tertiary center between 2006 and 2019.

Methods

We adopted a group-based trajectory model to categorize CKD patients into three trajectories according to estimated glomerular filtration rate (eGFR) changes. A repeated-measures linear mixed model was used to estimate the concurrent biomarker trends in a 2-year period before dialysis and to examine the differences among trajectory groups. A total of 15 biomarkers were analyzed, including urine protein, serum uric acid, albumin, lipid, electrolytes, and hematologic markers.

Results

Using longitudinal data from 2 years before dialysis initiation, 1758 CKD patients were included. We identified three distinct eGFR trajectories: persistently low eGFR levels, progressive loss of eGFR, and accelerated loss of eGFR. Eight of the 15 biomarkers showed distinct patterns among the trajectory groups. Compared with the group with persistently low eGFR values, the other two groups were associated with a more rapid increase in the blood urea nitrogen (BUN) level and urine protein-creatinine ratio (UPCR), especially in the year before dialysis initiation, and a more rapid decline in hemoglobin and platelet counts. A rapid eGFR decline was associated with lower levels of albumin and potassium, and higher levels of mean corpuscular hemoglobin concentration (MCHC) and white blood cell (WBC). The albumin level in the group with an accelerated loss of eGFR was below the normal range.

Conclusion

Using longitudinal data, we delineated the changes in CKD biomarkers with disease progression. The results provide information to clinicians and clues to elucidate the mechanism of CKD progression.

Association of polypharmacy with incidence of CKD: a retrospective cohort study

BACKGROUND

Polypharmacy is common in patients with chronic kidney disease (CKD) and is associated with a decline in kidney function. However, its impact on patients without CKD has not been adequately elucidated. Therefore, we aimed to investigate the association between polypharmacy and the incidence of CKD.

METHODS

We conducted retrospective cohort study using 1221 participants who were enrolled in the Fukushima Cohort Study with one or more risk factors of CKD, an estimated glomerular filtration rate (eGFR) of ≥ 60 mL/min/1.73 m², and without proteinuria. Participants were categorized into three groups based on the number of medications: non-polypharmacy, 0-4 medications; polypharmacy, 5-9 medications; and hyper-polypharmacy, ≥ 10 medications.

RESULTS

The median age was 62 years, 49% were men, the median eGFR was 75.4 ml/min/1.73 m², and the median number of medications was 5. Polypharmacy and hyper-polypharmacy were noted in 506 (41%) and 250 (20%) participants, respectively. During follow-up, 288 participants developed CKD and 67 cardiovascular events were observed. Compared to the non-polypharmacy group, the hyper-polypharmacy group had a higher risk of CKD and cardiovascular events. The adjusted hazard ratios were 1.41 (95% CI1.01-1.99) and 2.24 (95% CI1.05-4.78) for the incidence of CKD and cardiovascular events, respectively. Sensitivity analyses yielded similar findings for the restricted cubic spline function models.

CONCLUSIONS

Hyper-polypharmacy is associated with a higher risk of CKD and cardiovascular events.

Mediation of serum albumin in the association of serum potassium with mortality in Chinese dialysis patients: a prospective cohort study

BACKGROUND

The clinical importance of hypokalemia is likely underrecognized in Chinese dialysis patients, and whether its clinical effect was mediated by serum albumin is not fully elucidated. This study aimed to explore the association between serum potassium and mortality in dialysis patients of a Chinese nationwide multicenter cohort, taking albumin as a consideration.

METHODS

This was a prospective nation-wide multicenter cohort study. Restricted cubic splines were used to test the linearity of serum potassium and relationships with all-cause (AC) and cardiovascular (CV) mortality and a subsequent two-line piecewise linear model was fitted to approach the nadir. A mediation analysis was performed to examine relations of albumin to potassium and mortalities.

RESULTS

A total of 10,027 patients were included, of whom 6605 were peritoneal dialysis and 3422 were hemodialysis patients. In the overall population, the mean age was 51.7 ± 14.8 years, 55.3%(5546/10,027) were male, and the median dialysis vintage was 13.60 (4.70, 39.70) months. Baseline serum potassium was 4.30 ± 0.88 mmol/L. After a median follow-up period of 26.87 (14.77, 41.50) months, a U-shape was found between potassium and mortality, and a marked increase in risk at lower potassium but a moderate elevation in risk at higher potassium were observed. The nadir for AC mortality risk was estimated from piecewise linear models to be a potassium concentration of 4.0 mmol/L. Interestingly, the significance of the association between potassium and mortality was attenuated when albumin was introduced into the extended adjusted model. A subsequent significant mediation by albumin for potassium and AC and CV mortalities were found ( P < 0.001 for both), indicating that hypokalemia led to higher mortality mediated by low serum albumin, which was a surrogate of poor nutritional status and inflammation.

CONCLUSIONS

Associations between potassium and mortalities were U-shaped in the overall population. The nadir for AC mortality risk was at a potassium of 4.0 mmol/L. Serum albumin mediated the association between potassium and AC and CV mortalities.

Chronic Hyperkaliemia in Chronic Kidney Disease: An Old Concern with New Answers

Increasing potassium intake ameliorates blood pressure (BP) and cardiovascular (CV) prognoses in the general population; therefore the World Health Organization recommends a high-potassium diet (90–120 mEq/day). Hyperkalaemia is a rare condition in healthy individuals due to the ability of the kidneys to effectively excrete dietary potassium load in urine, while an increase in serum K⁺ is prevalent in patients with chronic kidney disease (CKD). Hyperkalaemia prevalence increases in more advanced CKD stages, and is associated with a poor prognosis. This scenario generates controversy on the correct nutritional approach to hyperkalaemia in CKD patients, considering the unproven link between potassium intake and serum K⁺ levels. Another concern is that drug-induced hyperkalaemia leads to the down-titration or withdrawal of renin-angiotensin system inhibitors (RASI) and mineralocorticoids receptors antagonists (MRA) in patients with CKD, depriving these patients of central therapeutic interventions aimed at delaying CKD progression and decreasing CV mortality. The new K⁺-binder drugs (Patiromer and Sodium-Zirconium Cyclosilicate) have proven to be adequate and safe therapeutic options to control serum K⁺ in CKD patients, enabling RASI and MRA therapy, and possibly, a more liberal intake of fruit and vegetables.

Association between Serum Inorganic Phosphorus Levels and Adverse Outcomes in Chronic Kidney Disease: The Fukushima CKD Cohort Study

Objective Although an association between serum inorganic phosphorus levels and a poor prognosis has been noted in dialysis patients, these associations have been insufficiently reported in non-dialysis-dependent chronic kidney disease (NDD-CKD) patients. This study attempted to determine the association between serum inorganic phosphorus levels and adverse outcomes in Japanese NDD-CKD patients. Methods We investigated the relationships between serum inorganic phosphorus levels and adverse outcomes, such as kidney events, cardiovascular events, and all-cause death, in Japanese NDD-CKD patients using longitudinal data from the Fukushima CKD Cohort Study with a median follow-up period of 2.8 years. The study evaluated 822 patients with NDD-CKD enrolled between June 2012 and July 2014. A kidney event was defined as a combination of doubling of the baseline serum creatinine or end-stage renal disease. Cox regression was performed to analyze the relationships of the quartile of the serum inorganic phosphorus with kidney events, cardiovascular events, and all-cause death. Results The frequency of kidney events per 1,000 person-years exhibited a U-shaped distribution based on serum inorganic phosphorus levels, with these levels not significantly associated with an increased risk of cardiovascular events and all-cause death. A multivariable Cox regression analysis showed an increased risk of kidney events for the highest quartile of the serum inorganic phosphorus levels (≥3.7 mg/dL) versus the second quartile (2.9-3.2 mg/dL, hazard ratio, 3.30; 95% confidence interval, 1.50-7.28; p=0.003). There were no significant associations between the serum calcium levels and adverse outcomes. Conclusion Serum inorganic phosphorus levels were associated with an increased risk of CKD progression in Japanese NDD-CKD patients.

Association of Polypharmacy with Kidney Disease Progression in Adults with CKD

BACKGROUND AND OBJECTIVE

Polypharmacy is common in patients with CKD and reportedly associated with adverse outcomes. However, its effect on kidney outcomes among patients with CKD has not been adequately elucidated. Hence, this investigation was aimed at exploring the association between polypharmacy and kidney failure requiring KRT.

DESIGN, SETTING, PARTICIPANTS, AND MEASUREMENTS

We retrospectively examined 1117 participants (median age, 66 years; 56% male; median eGFR, 48 ml/min per 1.73 m²) enrolled in the Fukushima CKD Cohort Study to investigate the association between the number of prescribed medications and adverse outcomes such as kidney failure, all-cause mortality, and cardiovascular events in Japanese patients with nondialysis-dependent CKD. Polypharmacy and hyperpolypharmacy were defined as the regular use of 5-9 and ≥10 medications per day, respectively.

RESULTS

The median number of medications was eight; the prevalence of polypharmacy and hyperpolypharmacy was each 38%. During the observation period (median, 4.8 years), 120 developed kidney failure, 153 developed cardiovascular events, and 109 died. Compared with the use of fewer than five medications, adjusted hazard ratios (95% confidence intervals) associated with polypharmacy and hyperpolypharmacy were 2.28 (1.00 to 5.21) and 2.83 (1.21 to 6.66) for kidney failure, 1.60 (0.85 to 3.04) and 3.02 (1.59 to 5.74) for cardiovascular events, and 1.25 (0.62 to 2.53) and 2.80 (1.41 to 5.54) for all-cause mortality.

CONCLUSIONS

The use of a high number of medications was associated with a high risk of kidney failure, cardiovascular events, and all-cause mortality in Japanese patients with nondialysis-dependent CKD under nephrology care.