Adequacy of Dialysis and Incidence of Atrial Fibrillation in Patients Undergoing Hemodialysis.

BACKGROUND: Atrial fibrillation (AF) can lead to stroke, heart failure, and mortality and has a greater prevalence in dialysis patients than in the general population. Several studies have suggested that uremic toxins may contribute to the development of AF. However, the association between dialysis adequacy and incident AF has not been well established. METHODS: In this retrospective nationwide cohort study, we analyzed data from the Korean National Periodic Hemodialysis Quality Assessment from 2013 to 2015 of patients who received outpatient maintenance hemodialysis 3× a week. The main exposure was single pooled Kt/V (spKt/V), which is the dialysis adequacy index, and the primary outcome was the development of AF. For the primary analysis, patients were categorized into quartiles according to baseline spKt/V. The lowest quartile, representing the lowest adequacy, was used as the reference group. Fine-Gray subdistribution hazard models were used, treating all-cause mortality as a competing risk. RESULTS: Of 25 173 patients, the mean age was 60 (51-69) years, and 14 772 (58.7%) were men. During a median follow-up of 5.7 years, incident AF occurred in a total of 3883 (15.4%) patients. Participants with a higher spKt/V tended to have lower AF incidence. In survival analysis, a graded association was observed between the risk of incident AF and spKt/V quartiles: subdistribution hazard ratios and 95% CIs for the second, third, and the highest quartile compared with the lowest quartile were 0.90 (95% CI, 0.82-0.98), 0.84 (95% CI, 0.77-0.93), and 0.79 (95% CI, 0.72-0.88), respectively. CONCLUSIONS: This nationwide cohort study showed that a higher spKt/V is associated with a reduced risk of incident AF. These findings suggests that reducing uremic toxin burden through enhanced dialysis clearance may be associated with a lower risk of AF development in patients undergoing maintenance hemodialysis.

Association of ketone bodies with incident CKD and death: A UK Biobank study.

AIMS: Although cellular and animal models have suggested a protective effect of ketone bodies (KBs), clinical data are still lacking to support these findings. This study aimed to investigate the association of KB levels with incident chronic kidney disease (CKD) and death. METHODS: This was a prospective cohort study of 87,899 UK Biobank participants without baseline CKD who had plasma levels of ß-hydroxybutyrate, acetoacetate, and acetone levels measured at the time of enrollment. The main predictor was plasma total KB, which was the sum of the aforementioned three KBs. The primary outcome was a composite of incident CKD, or all-cause mortality. Secondary outcomes included the individual components of the primary outcome. RESULTS: During a median follow-up of 11.9 years, a total of 8,145 primary outcome events occurred (incidence rate 8.0/1,000 person-years). In the multivariable Cox model, a 1-standard deviation increase in log total KB was associated with a 7 % [adjusted hazard ratio (aHR), 1.07; 95 % confidence interval (CI), 1.05-1.10] higher risk of the primary outcome. When stratified into quartiles, the aHR (95 % CI) for Q4 versus Q1 was 1.18 (1.11-1.27). This association was consistent for incident CKD (aHR, 1.04; 95 % CI, 1.01-1.07), and all-cause mortality (aHR, 1.10; 95 % CI, 1.07-1.13). Compared with Q1, Q4 was associated with a 12 % (aHR 1.12; 95 % CI 1.02-1.24) and 26 % (aHR 1.26; 95 % CI 1.15-1.37) higher risk of incident CKD and all-cause mortality, respectively. CONCLUSIONS: Higher KB levels were independently associated with higher risk of incident CKD and death.

Sweetened Beverage Intake and Incident Chronic Kidney Disease in the UK Biobank Study.

Importance: An increasing body of evidence indicates an association between consuming sugar or its alternatives and cardiometabolic diseases. However, the effects of the consumption of sugar-sweetened beverages, artificially sweetened beverages, and natural juices on kidney health remain unclear. Objective: To investigate the association of the intake of sugar-sweetened beverages, artificially sweetened beverages, and natural juices with the risk of chronic kidney disease (CKD), and the effect of substituting these beverage types for one another on this association. Design, Setting, and Participants: This prospective, population-based cohort study analyzed data from the UK Biobank. Participants without a history of CKD who completed at least 1 dietary questionnaire were included. The follow-up period was from the date of the last dietary questionnaire until October 31, 2022, in England; July 31, 2021, in Scotland; and February 28, 2018, in Wales. Data were analyzed from May 1 to August 1, 2023. Exposures: Consumption of sugar-sweetened beverages, artificially sweetened beverages, and natural juices. Main Outcomes and Measures: The primary outcome was incident CKD. Multivariable Cox proportional hazards models were used to estimate the associations between the 3 beverage types and incident CKD. A substitution analysis was used to evaluate the effect on the associations of substituting one beverage type for another. Results: A total of 127 830 participants (mean [SD] age, 55.2 [8.0] years; 66 180 female [51.8%]) were included in the primary analysis. During a median (IQR) follow-up of 10.5 (10.4-11.2) years, 4459 (3.5%) cases of incident CKD occurred. The consumption of more than 1 serving per day of sugar-sweetened beverages was associated with higher risk of incident CKD (adjusted hazard ratio [AHR], 1.19 [95% CI, 1.05-1.34]) compared with not consuming sugar-sweetened beverages. The AHR for participants consuming more than 0 to 1 serving per day of artificially sweetened beverages was 1.10 (95% CI, 1.01-1.20) and for consuming more than 1 serving per day was 1.26 (95% CI, 1.12-1.43) compared with consuming no artificially sweetened beverages. By contrast, there was no significant association between natural juice intake and incident CKD (eg, for >1 serving per day: HR, 0.99 [95% CI, 0.87-1.11]; P = .10). Substituting sugar-sweetened beverages with artificially sweetened beverages did not show any significant difference in the risk of CKD (HR, 1.03 [95% CI, 0.96-1.10]). Conversely, replacing 1 serving per day of sugar-sweetened beverage with natural juice (HR, 0.93 [95% CI, 0.87-0.97]) or water (HR, 0.93 [95% CI, 0.88-0.99]) or replacing 1 serving per day of artificially sweetened beverage with natural juice (HR, 0.90 [95% CI, 0.84-0.96]) or water (HR, 0.91 [95% CI, 0.86-0.96]) was associated with a reduced risk of incident CKD. Conclusions and Relevance: Findings from this cohort study suggest that lower consumption of sugar-sweetened beverages or artificially sweetened beverages may reduce the risk of developing CKD.

Higher potassium intake is associated with a lower risk of chronic kidney disease: population-based prospective study.

BACKGROUND: High-potassium intake is associated with a lower risk of cardiovascular disease. However, the association between potassium intake and the development of chronic kidney disease (CKD) remains unclear. OBJECTIVE: The objective of this study was to investigate whether potassium intake is associated with outcomes of incident CKD. METHODS: This is a population-based prospective observational cohort study from the UK Biobank cohort between 2006 and 2010. We included 317,162 participants without CKD from the UK Biobank cohort. The main predictor was spot urine potassium-to-creatinine ratio (KCR). The primary outcome was incident CKD, which was defined by the International Classification of Disease 10 codes or Operating Procedure Codes Supplement 4 codes. RESULTS: At baseline, individuals with higher KCR had lower blood pressure, body mass index, and inflammation, and were less likely to have diabetes and hypertension. During a median follow-up of 11.9 y, primary outcome events occurred in 15,246 (4.8%) participants. In the cause-specific model, the adjusted hazard ratio (aHR) per 1-standard deviation increase in KCR for incident CKD was 0.90 [95% confidence interval (CI): 0.89, 0.92]. Compared with quartile 1 of KCR, the aHRs (95% CIs) for quartiles 2-4 were 0.98 (0.94, 1.02), 0.90 (0.86, 0.95), and 0.80 (0.76, 0.84), respectively. In sensitivity analysis with different definitions of CKD, the results were similar. In addition, further analysis with dietary potassium intake also showed a negatively graded association with the primary outcome. CONCLUSIONS: Higher urinary potassium excretion and intake were associated with a lower risk of incident CKD.

Difference Between Estimated GFR Based on Cystatin C Versus Creatinine and Incident Atrial Fibrillation: A Cohort Study of the UK Biobank.

RATIONALE & OBJECTIVE: The difference between cystatin C-based and creatinine-based estimated glomerular filtration rate (eGFRdiff) has been suggested to reflect factors distinct from kidney function that are associated with cardiovascular risk. However, the association between eGFRdiff and atrial fibrillation (AF) risk has not been extensively evaluated. STUDY DESIGN: Prospective cohort study. SETTING & PARTICIPANTS: Using data from the UK Biobank, this study included 363,494 participants with measured serum creatinine and cystatin C levels and without a prior diagnosis of AF or a history of related procedures. EXPOSURE: Estimated GFRdiff, calculated as cystatin C-based eGFR minus creatinine-based eGFR. Estimated GFRdiff was also categorized as negative (<-15mL/min/1.73m2), midrange (-15 to 15mL/min/1.73m2), or positive (≥15mL/min/1.73m2). OUTCOME: Incident AF. ANALYTICAL APPROACH: Subdistribution hazard models were fit, treating death that occurred before development of AF as a competing event. RESULTS: During the median follow-up period of 11.7 years, incident AF occurred in 18,994 (5.2%) participants. In the multivariable-adjusted model, participants with a negative eGFRdiff had a higher risk of incident AF (subdistribution HR [SHR], 1.25 [95% CI, 1.20-1.30]), whereas participants with a positive eGFRdiff had a lower risk of AF (SHR, 0.81 [95% CI, 0.77-0.87]) compared with those with a midrange eGFRdiff. When eGFRdiff was treated as a continuous variable in the adjusted model, every 10mL/min/1.73m2 higher eGFRdiff was associated with a 0.90-fold decrease in the risk of incident AF. LIMITATIONS: A single measurement of baseline serum creatinine and cystatin C levels. CONCLUSIONS: The difference between cystatin C- and creatinine-based eGFRs was associated with the risk of AF development. A higher eGFRdiff was associated with a lower risk of AF. These findings may have implications for the management of patients at risk of incident AF. PLAIN-LANGUAGE SUMMARY: The difference between cystatin C-based estimated glomerular filtration rate (eGFR) and creatinine-based eGFR has recently gained attention as a potential indicator of cardiovascular outcomes influenced by factors other than kidney function. This study investigated the association between the differences in 2 eGFRs (cystatin C-based eGFR minus creatinine-based eGFR) and incident atrial fibrillation (AF) among>340,000 participants from the UK Biobank Study. Compared with those with a near zero eGFR difference, participants with a negative eGFR difference had a higher risk of AF, while those with a positive eGFR difference had a lower risk. These findings suggest that measuring eGFR differences may help identify individuals at a higher risk of developing AF.

Insomnia in patients on incident maintenance dialysis and the risk of major acute cardio-cerebrovascular events and all-cause mortality.

BACKGROUND AND HYPOTHESIS: Insomnia is a known risk factor for cardio-cerebrovascular disease in the general population; however, its effect on cardio-cerebrovascular outcomes in end-stage kidney disease patients is unclear. Therefore, this study aimed to investigate the association between cardio-cerebrovascular outcomes and insomnia in patients who initiated maintenance dialysis. METHODS: This study used nationwide Korean health insurance claims data to analyze 79 420 patients who initiated maintenance dialysis from January 2009 to December 2017. Insomnia was defined using claim codes and sleep medication prescription data. Patients were categorized according to the presence of insomnia before and after dialysis initiation: a) no insomnia, b) insomnia before dialysis only (improved insomnia), c) insomnia after dialysis only (developed insomnia), and d) insomnia in both periods (persistent insomnia). The primary and secondary outcomes were major adverse cardiac and cerebrovascular events (MACCE) and all-cause mortality, respectively. The outcome risks were estimated by Cox regression models with inverse probability of treatment weighting. RESULTS: The mean age was 61.4 ± 13.4 years, and 39.7% were women. During the transition period from pre-dialysis to maintenance dialysis, 13.2% experienced insomnia. The insomnia groups showed significantly higher risks for MACCE (weighted hazard ratios [95% confidence intervals]: developed insomnia, 1.26 [1.25-1.28]; improved insomnia, 1.31 [1.29-1.33]; persistent insomnia, 1.39 [1.37-1.41]) and higher all-cause mortality risks than the no insomnia group. The insomnia related cardio-cerebrovascular disease risk elevation was more prominent in younger and male patients. CONCLUSIONS: Insomnia may increase cardio-cerebrovascular disease and all-cause mortality risk among end-stage kidney disease patients who initiate maintenance dialysis.

Association of Plant Protein Intake With Risk of Incident CKD: A UK Biobank Study.

RATIONALE & OBJECTIVE: Data suggest that various dietary interventions slow kidney disease progression and improve clinical outcomes for those with chronic kidney disease (CKD). However, the association between plant protein intake and incident CKD has been uncertain. STUDY DESIGN: Prospective cohort study. SETTING & PARTICIPANTS: 117,809 participants who completed at least 1 dietary questionnaire and had an estimated glomerular filtration rate (eGFR) ≥ 60mL/min/1.73m2, a urinary albumin-creatinine ratio (UACR)<30mg/g, and no history of CKD. EXPOSURE: Daily plant protein intake in g/kg/day. OUTCOME: Incident CKD based on the International Classification of Diseases, 10th Revision (ICD-10) or the Office of Population Censuses and Surveys Classification of Interventions and Procedures, version 4 (OPCS-4) codes. ANALYTICAL APPROACH: A cause-specific proportional hazards analysis incorporating competing risks that treated death occurring before incident CKD as a competing event. RESULTS: During a median follow-up period of 9.9 years, incident CKD occurred in 3,745 participants (3.2%; incidence rate, 3.2 per 1,000 person-years). In a multivariable model, the adjusted hazard ratio (AHR) for the second, third, and highest quartiles of plant protein intake was 0.90 (95% CI, 0.82-0.99), 0.83 (95% CI, 0.75-0.92), and 0.82 (95% CI, 0.73-0.93), respectively, compared with the lowest quartile. Modeled as a continuous variable, the AHR per 0.1g/kg/day plant protein intake increase was 0.96 (95% CI, 0.93-0.99). This beneficial association was also consistent in secondary analyses for which CKD was defined based on codes or 2 consecutive measures of eGFR<60mL/min/1.73m2 or UACR>30mg/g. Various sensitivity analyses demonstrated consistent findings. LIMITATIONS: Potential incomplete dietary assessments; limited generalizability due to the characteristics of participants in the UK Biobank Study. CONCLUSIONS: In this large, prospective cohort study, greater dietary plant protein intake was associated with a lower risk of incident CKD. Further interventional studies demonstrating the kidney-protective benefits of plant protein intake are warranted. PLAIN-LANGUAGE SUMMARY: Plant-based diets confer various health benefits, including lowering the risk of cardiovascular disease and certain cancers. However, the relationship between plant protein intake and the risk of chronic kidney disease (CKD) remains unclear. Our study investigated the association between plant protein intake and the development of CKD. Using the UK Biobank Study data, we found that participants with a higher plant protein intake had a lower risk of developing CKD. Our finding suggests that a higher dietary intake of plant-based protein may be beneficial for kidney health and provides insight into dietary interventions to prevent CKD in primary care settings.

Impact of ABO incompatibility and early antibody-mediated rejection on chronic antibody-mediated rejection in kidney transplant patients.

INTRODUCTION: Early antibody-mediated rejection has been reported to increase chronic antibody-mediated rejection and decrease graft survival in kidney transplantation. However, the impact of early antibody-mediated rejection in ABO-incompatible kidney transplantation remains unclear. METHODS: We retrospectively analyzed living-donor kidney transplantation patients from two Korean centers. Patients were categorized based on ABO compatibility and early antibody-mediated rejection within 1 year. The primary outcome was chronic antibody-mediated rejection. The secondary outcomes were production of de novo donor-specific antibody and composite kidney outcome, defined as graft loss or a decline in estimated glomerular filtration rate to below 30 mL/min/1.73 m2. RESULTS: A total of 1639 patients were analyzed, including 1292 patients who underwent ABO-compatible kidney transplantation and 347 patients who underwent ABO-incompatible kidney transplantation. ABO-incompatible kidney transplantation had a lower risk of de novo donor-specific antibody production (hazard ratio [HR] 0.68, 95% confidence interval [CI] 0.48-0.95) and chronic antibody-mediated rejection (HR 0.33, 95% CI 0.12-0.92) with a comparable risk of the composite kidney outcome (HR 1.06, 95% CI 0.71-1.59) compared to ABO-compatible kidney transplantation. When outcomes of ABO-incompatible kidney transplantation were analyzed according to early antibody-mediated rejection, ABO-incompatible kidney transplantation without antibody-mediated rejection had a lower risk of de novo donor-specific antibody production (HR 0.60, 95% CI 0.41-0.88) and chronic antibody-mediated rejection (HR 0.28, 95% CI 0.09-0.91) than ABO-compatible kidney transplantation without antibody-mediated rejection. However, ABO-incompatible kidney transplantation with antibody-mediated rejection showed a higher risk of de novo donor-specific antibody production and similar risk of chronic antibody-mediated rejection compared to ABO-compatible kidney transplantation without antibody-mediated rejection. CONCLUSIONS: ABO-incompatible kidney transplantation showed a lower risk of de novo donor-specific antibody production and chronic antibody-mediated rejection compared to ABO-compatible kidney transplantation; however, early antibody-mediated rejection abrogated these beneficial effects of ABO-incompatible kidney transplantation.

Glycemic Control and Adverse Clinical Outcomes in Patients with Chronic Kidney Disease and Type 2 Diabetes Mellitus: Results from KNOW-CKD.

BACKGRUOUND: The optimal level of glycosylated hemoglobin (HbA1c) to prevent adverse clinical outcomes is unknown in patients with chronic kidney disease (CKD) and type 2 diabetes mellitus (T2DM). METHODS: We analyzed 707 patients with CKD G1-G5 without kidney replacement therapy and T2DM from the KoreaN Cohort Study for Outcome in Patients With Chronic Kidney Disease (KNOW-CKD), a nationwide prospective cohort study. The main predictor was time-varying HbA1c level at each visit. The primary outcome was a composite of development of major adverse cardiovascular events (MACEs) or all-cause mortality. Secondary outcomes included the individual endpoint of MACEs, all-cause mortality, and CKD progression. CKD progression was defined as a ≥50% decline in the estimated glomerular filtration rate from baseline or the onset of end-stage kidney disease. RESULTS: During a median follow-up of 4.8 years, the primary outcome occurred in 129 (18.2%) patients. In time-varying Cox model, the adjusted hazard ratios (aHRs) for the primary outcome were 1.59 (95% confidence interval [CI], 1.01 to 2.49) and 1.99 (95% CI, 1.24 to 3.19) for HbA1c levels of 7.0%-7.9% and ≥8.0%, respectively, compared with <7.0%. Additional analysis of baseline HbA1c levels yielded a similar graded association. In secondary outcome analyses, the aHRs for the corresponding HbA1c categories were 2.17 (95% CI, 1.20 to 3.95) and 2.26 (95% CI, 1.17 to 4.37) for MACE, and 1.36 (95% CI, 0.68 to 2.72) and 2.08 (95% CI, 1.06 to 4.05) for all-cause mortality. However, the risk of CKD progression did not differ between the three groups. CONCLUSION: This study showed that higher HbA1c levels were associated with an increased risk of MACE and mortality in patients with CKD and T2DM.

Trends in the association between body mass index and blood pressure among 19-year-old men in Korea from 2003 to 2017.

The strength of association between the body mass index (BMI) and blood pressure (BP) varies with population and time. Therefore, identifying the trends in BMI-BP association in adolescents can help predict the upcoming metabolic and cardiovascular disease burden. For this reason, from physical examination data collected from 2003 to 2017, a total of 5,133,246 Korean men aged 19 years were assessed for the annual trends and changes in the BMI-BP association. During the 15-year period, the mean BMI increased from 22.5 to 23.5 kg/m2, and the prevalence of obesity increased from 16.7 to 21.4%. Meanwhile, the mean systolic BP (SBP) decreased from 122.8 to 122.3 mmHg in the first year and gradually increased to 125.9 mmHg afterward. The diastolic BP (DBP) decreased from 71.5 to 70.0 mmHg in the first 4 years and then rose to 74.8 mmHg in the following years. The association analysis between BMI and SBP resulted in an annual increase in the correlation coefficient (SBP: 0.257-0.495, DBP: 0.164-0.413). The regression coefficient similarly increased between 2003 and 2015 but slightly decreased between 2015 and 2017 (SBP: 0.896-1.569, DBP: 0.405-0.861). The BMI-BP association increased over time (coefficient of the interaction term > 0, P < 0.001). Moreover, as the BMI increased, the annual increase in BP and BP per unit BMI also increased. In conclusion, this study emphasized a continuous shift towards obesity in BMI distribution and intensifying BMI-BP association over time in young men. Further research on factors affecting this BMI-BP association is needed to fully validate the potential applications of this hypothesis.

Sex disparities and adverse cardiovascular and kidney outcomes in patients with chronic kidney disease: results from the KNOW-CKD.

AIMS: Longitudinal studies of the association between sex and adverse clinical outcomes in patients with chronic kidney disease (CKD) are scarce. We assessed whether major outcomes may differ by sex among CKD patients. METHODS: We analyzed a total of 1780 participants with non-dialysis CKD G1-5 from the KoreaN cohort study for Outcome in patients with Chronic Kidney Disease (KNOW-CKD). The primary outcome was a composite of non-fatal cardiovascular events or all-cause mortality. Secondary outcomes included fatal and non-fatal cardiovascular events, all-cause mortality, and a composite kidney outcome of ≥ 50% decline in estimated glomerular filtration rate from baseline or the onset of end-stage kidney disease. RESULTS: There were 1088 (61%) men and 692 (39%) women in the study cohort. The proportion of smokers was significantly higher in men (24% vs. 3%). During 8430 person-years of follow-up, 201 primary outcome events occurred: 144 (13%) in men and 57 (8%) in women, with corresponding incidence rates of 2.9 and 1.7 per 100 person-years, respectively. In multivariable Cox models, men were associated with a 1.58-fold (95% CI 1.06-2.35) higher risk of composite outcome. Propensity score matching analysis revealed similar findings (HR 1.81; 95% CI 1.14-2.91). Risk of all-cause mortality was significantly higher in men of the matched cohort. However, there was no difference in the risk of CKD progression. In the subgroup with coronary artery calcium (CAC) measurements, men had a higher likelihood of CAC progression. CONCLUSIONS: In Korean CKD patients, men were more likely to experience adverse cardiovascular events and death than women.