Recalibration and validation of the Charlson Comorbidity Index in acute kidney injury patients underwent continuous renal replacement therapy

Background

Comorbid conditions impact the survival of patients with severe acute kidney injury (AKI) who require continuous renal replacement therapy (CRRT). The weights assigned to comorbidities in predicting survival vary based on type of index, disease, and advances in management of comorbidities. We developed a modified Charlson Comorbidity Index (CCI) for use in patients with AKI requiring CRRT (mCCI-CRRT) and improved the accuracy of risk stratification for mortality.

Methods

A total of 828 patients who received CRRT between 2008 and 2013, from three university hospital cohorts was included to develop the comorbidity score. The weights of the comorbidities were recalibrated using a Cox proportional hazards model adjusted for demographic and clinical information. The modified index was validated in a university hospital cohort (n = 919) using the data of patients treated from 2009 to 2015.

Results

Weights for dementia, peptic ulcer disease, any tumor, and metastatic solid tumor were used to recalibrate the mCCI-CRRT. Use of these calibrated weights achieved a 35.4% (95% confidence interval [CI], 22.1%–48.1%) higher performance than unadjusted CCI in reclassification based on continuous net reclassification improvement in logistic regression adjusted for age and sex. After additionally adjusting for hemoglobin and albumin, consistent results were found in risk reclassification, which improved by 35.9% (95% CI, 23.3%–48.5%).

Conclusion

The mCCI-CRRT stratifies risk of mortality in AKI patients who require CRRT more accurately than does the original CCI, suggesting that it could serve as a preferred index for use in clinical practice.

Low bone mineral density is associated with coronary arterial calcification progression and incident cardiovascular events in patients with chronic kidney disease

Background

Although it is well known that low bone mineral density (BMD) is associated with an increased risk of cardiovascular disease (CVD) and mortality in the general population, the prognostic role of bone mineral density (BMD) has not been established in the chronic kidney disease (CKD) population. Therefore we aimed to evaluate the association between BMD and the risk of CVD and cardiovascular mortality in patients with predialysis CKD.

Methods

This prospective cohort study was conducted with 1957 patients with predialysis CKD Stages 1–5. BMD was measured using dual-energy X-ray absorptiometry and coronary arterial calcification (CAC) scores were evaluated using coronary computed tomography. The primary outcome was a major adverse cardiovascular event (MACE).

Results

When patients were classified based on total hip BMD T-score tertiles stratified by sex, the lowest BMD tertile was significantly associated with an increased risk of MACE {hazard ratio 2.16 [95% confidence interval (CI) 1.25–3.74]; P = 0.006}. This association was also shown with BMD at the femur neck but not with BMD at lumbar spine. In the subgroup of 977 patients with follow-up CACs at their fourth year, 97 (9.9%) showed accelerated CAC progression (>50/year), and BMD was inversely associated with accelerated CAC progression even after adjusting for the baseline CAC score [odds ratio 0.75 (95% CI 0.58–0.99); P = 0.039]. In addition, baseline CAC was associated with an increased risk of MACEs after adjusting for total hip T-score.

Conclusions

Low BMD was significantly associated with CAC progression and MACEs in patients with predialysis CKD.

Theory of mind and hair cortisol in healthy young adults: the moderating effects of childhood trauma

Background: Experiences of negative social interactions and childhood trauma (CT) can lead to aberrant hypothalamic-pituitary-adrenal functions. Poor theory of mind (ToM) ability is related to increased social stress levels; however, studies on the relationship between ToM and cortisol remain scarce. Objective: This study aimed to evaluate the relationship between ToM and the hair cortisol concentration (HCC) in healthy young adults considering the moderating role of CT. Method: A total of 206 healthy young adults were divided into two groups based on an experience of moderate-to-severe childhood trauma (CT+ and CT-). To determine whether CT moderated the relationship between ToM and HCC, moderation analysis was conducted controlling for age, sex, years of education, and scores of perceived stress, depression, and anxiety. Results: CT+ individuals reported higher subjective stress perception and depressive symptoms than CT- individuals, whereas anxiety-related symptoms, ToM, and HCC were not different between the groups. The experience of CT significantly moderated the relationship between ToM and HCC. The association between poorer ToM ability and higher HCC was significant only in CT+ group. Conclusion: CT is a moderator of the association between ToM and HCC, indicating the importance of CT in social cognition and the stress response.

Therapeutic Potential of Targeting Periostin in the Treatment of Graves' Orbitopathy

Periostin is a matricellular protein that is ubiquitously expressed in normal human tissues and is involved in pathologic mechanism of chronic inflammatory and fibrotic disease. In this study we investigate periostin in the pathogenesis of Graves' orbitopathy (GO) using human orbital adipose tissue obtained from surgery and primary cultured orbital fibroblasts in vitro. POSTN (gene encoding periostin) expression in Graves' orbital tissues and healthy control tissues was studied, and the role of periostin in GO pathologic mechanism was examined through small-interfering RNA (siRNA)-mediated silencing. POSTN gene expression was significantly higher in Graves' orbital tissues than healthy control tissues in real-time PCR results, and immunohistochemical staining revealed higher expression of periostin in Graves' orbital tissues than normal tissues. Silencing periostin using siRNA transfection significantly attenuated TGF-β-induced profibrotic protein production and phosphorylated p38 and SMAD protein production. Knockdown of periostin inhibited interleukin-1 β -induced proinflammatory cytokines production as well as phosphorylation of NF-κB and Ak signaling protein. Adipocyte differentiation was also suppressed in periostin-targeting siRNA transfected GO cells. We hypothesize that periostin contributes to the pathogenic process of inflammation, fibrosis and adipogenesis of GO. Our study provides in vitro evidence that periostin may be a novel potential therapeutic target for the treatment of GO.

Body weight fluctuation is associated with rapid kidney function decline

OBJECTIVE

This study aimed to evaluate the effects of body weight fluctuations on kidney function deterioration in a prospective cohort of individuals with normal kidney function.

METHODS

Data were obtained from the Korean Genome and Epidemiology Study. Body weight fluctuations were determined using average successive variability (ASV), which was defined as the average absolute body weight change using repeated measurements for all participants. The decline of the estimated glomerular filtration rate (eGFR) over time was calculated using linear regression analysis of serial eGFR measurements for each patient. Rapid eGFR decline was defined as an average eGFR decline > 3 mL/min/1.73 m² per year.

RESULTS

A total of 6,790 participants were analyzed. During a median follow-up of 11.7 years, rapid eGFR decline was observed in 913 (13.4%) participants. When the participants were categorized into tertiles according to ASV, rapid eGFR decline was more prevalent in the highest ASV tertile group than in the lowest. Analyses using multiple logistic regression models revealed that the risk of rapid eGFR decline was increased in the highest ASV tertile group compared with the lowest (odds ratio: 1.66).

CONCLUSIONS

Body weight fluctuations were significantly associated with an increased risk of rapid kidney function decline in participants with normal kidney function.

Evaluating a shared decision-making intervention regarding dialysis modality: development and validation of self-assessment items for patients with chronic kidney disease

Background

Shared decision-making is a two-way symmetrical communication process in which clinicians and patients work together to achieve the best outcome. This study aimed to develop self-assessment items as a decision aid for choosing a dialysis modality in patients with chronic kidney disease (CKD) and to assess the construct validity of the newly developed items.

Methods

Five focus group interviews were performed to extract specific self-assessment items regarding patient values in choosing a dialysis modality. After survey items were refined, a survey of 330 patients, consisting of 152 hemodialysis (HD) and 178 peritoneal dialysis (PD) patients, was performed to validate the self-assessment items.

Results

The self-assessment for the decision aid was refined to 35 items. The structure of the final items appeared to have three dimensions of factors; health, lifestyle, and dialysis environment. The health factor consisted of 12 subscales (α = 0.724), the lifestyle factor contained 11 subscales (α = 0.624), and the dialysis environment factor was represented by 12 subscales (α = 0.694). A structural equation model analysis showed that the relationship between the decision aid factors (health, lifestyle, and dialysis environment), patients’ CKD perception, and cognition of shared decision-making differed between HD patients and PD patients.

Conclusion

We developed and validated self-assessment items as part of a decision aid to help patients with CKD. This attempt may assist CKD patients in making informed and shared decisions closely aligned with their values when considering dialysis modality.

Dialysis Adequacy and Risk of Dementia in Elderly Hemodialysis Patients

Objective: Dementia is prevalent among elderly patients undergoing hemodialysis. However, the association between dialysis adequacy and the risk of dementia is uncertain. Methods: A total of 10,567 patients aged >65 years undergoing maintenance hemodialysis who participated in a national hemodialysis quality assessment program were analyzed. The patients were classified into quartile groups based on single-pool Kt/V levels. The associations between single-pool Kt/V and the development of dementia, Alzheimer's disease (AD), and vascular dementia (VD) were examined. Results: The mean age of the patients was 72.9 years, and 43.4% were female. The mean baseline single-pool Kt/V level was 1.6 ± 0.3. During a median follow-up of 45.6 (45.6-69.9) months, there were 27.6, 23.9, and 2.8 events/1,000 person-years of overall dementia, AD, and VD, respectively. The incidences of overall dementia, AD, and VD were lowest in the highest single-pool Kt/V quartile group. Compared with the lowest single-pool Kt/V quartile, the risks of incident overall dementia and AD were significantly lower in the highest quartile [sub-distribution hazard ratio (sHR): 0.69, 95% confidence interval (CI): 0.58-0.82 for overall dementia; sHR: 0.69, 95% CI: 0.57-0.84 for AD]. Inverse relationships were found between the risks of developing overall dementia and AD, and single-pool Kt/V. However, no significant relationship was observed between single-pool Kt/V levels and VD development. Conclusions: Increased dialysis clearance was associated with a lower risk of developing dementia in elderly hemodialysis patients.

Effect of Childhood Trauma on the Association Between Stress-Related Psychological Factors and Hair Cortisol Level in Young Adults

OBJECTIVE

Relationship between hair cortisol concentration (HCC) and stress-related psychological measures are inconclusive, possibly due to overlooked heterogeneity regarding childhood trauma and a lack of comprehensive research on stress-related psychological factors. This study aims to compare young adults without history of childhood trauma to young adults who experienced childhood trauma using HCC and various stress-related psychological factors, as well as investigate the impacts of childhood trauma on the association between HCC and stress-related psychological measures.

METHODS

A total of 206 young, healthy adults were recruited. We divided participants into two groups depending on whether or not they had suffered moderate-to-severe childhood trauma (CT+ and CT-) and compared HCC and various stress-related psychological measures between groups. Using multiple linear regression analyses, we assessed the associations between HCC and stress-related psychological measures for each group.

RESULTS

We found no difference between the groups in HCC or the reported number of stressful life events in the past year; however, CT+ individuals reported higher stress perception, more depressive and anxiety-related symptoms, and more difficulties in emotion regulation than CT- individuals. HCC was associated with emotion dysregulation among the CT- individuals, but not among the CT+ individuals.

CONCLUSION

These findings suggest that history of childhood trauma should be considered in studies using HCC as a biomarker for stress in young adults. Furthermore, HCC might be a useful biomarker of stress and stress-related emotion dysregulation in individuals without moderate-to-severe childhood trauma.

Sex-specific association of hair cortisol concentration with stress-related psychological factors in healthy young adults

BACKGROUND

Hair cortisol concentration (HCC) has received attention as a useful marker of stress, but evidence on associations between psychological factors and cortisol concentration is inconsistent. The purpose of this study was to investigate the sex differences in the relationship between cortisol concentration and psychological factors in healthy young adults.

METHODS

A total of 205 (103 females, 102 males) healthy young adults participated. HCC and various stress-related psychological measures were compared between sexes. Multiple linear regression analyses were performed to assess associations between HCC and stress-related psychological measures for all participants and for each sex.

RESULTS

The difference in HCC according to sex was not significant. The reported number of stressful life events in the past year, stress perception, depressive and anxiety-related symptoms, and emotion dysregulation were not different between sexes, either. The association between HCC and emotion dysregulation was significant in females but not males.

CONCLUSION

We observed a sex-specific association between HCC and psychological factors. Our findings may imply that HCC could be a useful biomarker of stress and stress-related emotion dysregulation in healthy young women.

Increased Risk of Chronic Kidney Disease Associated With Weight Gain in Healthy Adults: Insight From Metabolic Profiles and Body Composition

Objective: Obesity is an established risk factor for kidney damage. In this study, we explored the long-term association of changes in body mass index (BMI) over time with incident chronic kidney disease (CKD).

Methods: For this analysis, 5,393 middle-aged adults without comorbidities in the Korean Genome and Epidemiology Study (KoGES) were included. Group-based trajectory modeling was used to determine the patterns of BMI change (decreasing, stable, and increasing BMI) between baseline and year 4. The primary outcome was the subsequent development of CKD from year 4. A multivariable Cox proportional hazards model was constructed to determine the risk of incident CKD according to BMI trajectories.

Results: During 55,327 person-years, incident CKD occurred in 354 (6.5%) participants; 6.0, 6.1, and 7.8 per 1,000 person-years across the trajectories, respectively (P = 0.005). In the multivariable-adjusted Cox proportional hazards model, the increasing BMI trajectory was associated with a 1.4-fold [hazard ratio (HR), 1.41; 95% CI, 1.06–1.87] a higher risk of incident CKD compared with stable BMI trajectory. This association was stronger for overweight and obese individuals. The HRs for CKD development in these two groups were 1.6 (95% CI, 1.06–1.87) and 2.2 (95% CI, 1.40–3.48), respectively. While the increasing BMI group was gaining weight, there were concomitant increases in blood pressure, insulin resistance, serum concentrations of total cholesterol, triglyceride, and high-sensitivity C-reactive protein (hs-CRP), and fat mass, but high-density lipoprotein (HDL)-cholesterol level and muscle-to-fat (MF) ratio decreased.

Conclusion: Weight gain is associated with an increased risk of incident CKD in healthy adults. This association is attributed to worsening metabolic profiles and increasing fat mass.

The difference between cystatin C- and creatinine-based eGFR is associated with adverse cardiovascular outcome in patients with chronic kidney disease

BACKGROUND AND AIMS

Decreased kidney function is an important risk factor for cardiovascular disease (CVD). However, assessing risk of CVD may be difficult when there is a gap between creatinine- and cystatin C-based estimated glomerular filtration rate (eGFR). We studied the association of the difference in eGFRs with major adverse cardiovascular events (MACE) in patients with chronic kidney disease (CKD).

METHODS

This prospective cohort study was conducted in 2076 patients with CKD stages based on the KDIGO guideline (eGFR categories of G1: ≥90; G 2: 60-89; G3: 30-59; G4: 15-29; G5: <15 mL/min/1.73 m² without kidney replacement therapy). The difference in eGFR (eGFR_diff) was calculated by subtracting the cystatin C-based eGFR (eGFR_cys) from the creatinine-based eGFR (eGFR_creat). The primary outcome was MACE, defined as non-fatal acute myocardial infarction and unstable angina, stroke, congestive heart failure, symptomatic arrhythmia, and cardiac death.

RESULTS

During a median follow-up of 4.1 years, MACE occurred in 147 patients (incidence rate, 15.0 per 1000 patient-years). When patients were categorized into baseline eGFR_diff tertiles, the highest tertile was associated with a significantly higher risk of MACE (hazard ratio, 2.12; 95% confidence interval [CI], 1.28-3.51) than the lowest tertile when adjusted for eGFR_creat, eGFR_cys, or eGFR based on both creatinine and cystatin C. Patients in the highest tertile had more baseline coronary artery calcification (CAC) than those in the lowest tertile (odds ratio [OR], 1.38; 95% CI, 1.03-1.86). In addition, 978 patients had data for both baseline and follow-up CAC at year 4. In this subgroup, baseline eGFR_diff was significantly associated with accelerated CAC progression (≥50/year) (OR, 1.03; 95% CI, 1.01-1.05).

CONCLUSIONS

A large positive difference between eGFR_creat and eGFR_cys was associated with a higher risk of MACE and faster CAC progression in patients with CKD. Therefore, careful monitoring of CVD is needed for patients with a higher eGFR_diff.

Outcomes of Remote Patient Monitoring for Automated Peritoneal Dialysis: A Randomized Controlled Trial

INTRODUCTION

We hypothesize that remote patient monitoring (RPM) for automated peritoneal dialysis (APD) and feedback could enhance patient self-management and improve outcomes. The aim of this study was to evaluate the efficacy of RPM-APD compared to traditional APD (T-APD) without RPM.

METHODS

In this multicenter, randomized controlled trial, patients on APD were randomized to T-APD (n = 29) or RPM-APD (n = 28) at 12 weeks and followed until 25 weeks. Health-related quality of life (HRQOL), patient and medical staff satisfaction with RPM-APD, and dialysis-related outcomes were compared between the 2 groups.

RESULTS

We found no significant differences in HRQOL scores at the time of enrollment and randomization between RPM-APD and T-APD. At the end of the study, the RPM-APD group showed better HRQOL for the sleep domain (p = 0.049) than the T-APD group and the T-APD group showed better HRQOL for the sexual function domain (p = 0.030) than the RPM-APD group. However, we found no significant interactions between the time and groups in terms of HRQOL. Different HRQOL domains significantly improved over time in patients undergoing RPM-APD (effects of kidney disease, p = 0.025) and T-APD (burden of kidney disease, p = 0.029; physical component summary, p = 0.048). Though medical staff satisfaction with RPM-APD was neutral, most patients were quite satisfied with RPM-APD (median score 82; possible total score 105 on 21 5-item scales) and the rating scores were maintained during the study period. We found no significant differences in dialysis adherence, accuracy, adequacy, overhydration status, blood pressure, or the number of unplanned visits between the 2 groups.

DISCUSSION/CONCLUSION

Although HRQOL and dialysis-related outcomes were comparable between RPM-APD and T-APD, RPM-APD was positive in terms of patient satisfaction. Further long-term and large-scale studies will be required to determine the efficacy of RPM-APD.

TRIAL REGISTRATION

CRIS identifier: KCT0003390, registered on December 14, 2018 - retrospectively registered, https://cris.nih.go.kr/cris/search/search_result_st01.jsp?seq=12348.

Erythropoiesis stimulating agent recommendation model using recurrent neural networks for patient with kidney failure with replacement therapy

In patients with kidney failure with replacement therapy (KFRT), optimizing anemia management in these patients is a challenging problem because of the complexities of the underlying diseases and heterogeneous responses to erythropoiesis-stimulating agents (ESAs). Therefore, we propose a ESA dose recommendation model based on sequential awareness neural networks. Data from 466 KFRT patients (12,907 dialysis sessions) in seven tertiary-care general hospitals were included in the experiment. First, a Hb prediction model was developed to simulate longitudinal heterogeneous ESA and Hb interactions. Based on the prediction model as a prospective study simulator, we built an ESA dose recommendation model to predict the required amount of ESA dose to reach a target hemoglobin level after 30 days. Each model's performance was evaluated in the mean absolute error (MAE). The MAEs presenting the best results of the prediction and recommendation model were 0.59 (95% confidence interval: 0.56-0.62) g/dL and 43.2 μg (ESAs dose), respectively. Compared to the results in the real-world clinical data, the recommendation model achieved a reduction of ESA dose (Algorithm: 140 vs. Human: 150 μg/month, P < 0.001), a more stable monthly Hb difference (Algorithm: 0.6 vs. Human: 0.8 g/dL, P < 0.001), and an improved target Hb success rate (Algorithm: 79.5% vs. Human: 62.9% for previous month's Hb < 10.0 g/dL; Algorithm: 95.7% vs. Human:73.0% for previous month's Hb 10.0-12.0 g/dL). We developed an ESA dose recommendation model for optimizing anemia management in patients with KFRT and showed its potential effectiveness in a simulated prospective study.

Association of Blood Pressure with Cardiovascular Outcome and Mortality: Results from the KNOW-CKD Study

BACKGROUND

Optimal BP control is a major therapeutic strategy to reduce adverse cardiovascular events and mortality in patients with CKD. We studied the association of BP with adverse cardiovascular outcome and all-cause death in patients with CKD.

METHODS

Among 2,238 participants from the KoreaN cohort study for Outcome in patients With CKD, 2,226 patients with baseline BP measurements were enrolled. Main predictor was SBP categorized by 5 levels: <110, 110-119, 120-129, 130-139, and ≥140 mmHg. Primary endpoint was a composite outcome of all-cause death or incident cardiovascular events. We primarily used marginal structural models using averaged and the most recent time-updated SBPs.

RESULTS

During a median follow-up of 10233.79 person-years (median 4.60 years), the primary composite outcome occurred in 240 (10.8%) participants, with a corresponding incidence rate of 23.5 (95% CI, 20.7-26.6) per 1,000 patient-years. Marginal structural models with averaged SBP showed a U-shaped relationship with the primary outcome. Compared to time-updated SBP of 110-119 mmHg, hazard ratios (95% CI) for <110, 120-129, 130-139, and ≥140 mmHg were 2.47 (1.48-4.11), 1.29 (0.80-2.08), 2.15 (1.26-3.69), and 2.19 (1.19-4.01), respectively. Marginal structural models with the most recent SBP also showed similar findings.

CONCLUSIONS

In Korean patients with CKD, there was a U-shaped association of SBP with the risk of adverse clinical outcome. Our findings highlight the importance of BP control and suggest a potential hazard of SBP <110 mmHg.

Reduction in proteinuria after immunosuppressive therapy and long-term kidney outcomes in patients with immunoglobulin A nephropathy

BACKGROUND/AIMS

Despite controversy regarding the benefits of immunosuppressive therapy in immunoglobulin A nephropathy (IgAN), clinical outcomes may vary depending on the patient's responsiveness to this therapy. This study evaluated long-term kidney outcomes according to the extent of proteinuria reduction after immunosuppression in IgAN patients.

METHODS

Among 927 patients with biopsy-proven IgAN, 127 patients underwent immunosuppression. Time-averaged urine protein-creatinine ratio before and within 1 year after start of immunosuppression were calculated, and responsiveness to immunosuppression was assessed as the reduction of proteinuria between the two periods. Patients were classified into tertiles according to the extent of proteinuria reduction. We compared the slopes of estimated glomerular filtration rate (eGFR) decline using a linear mixed model, and estimated hazard ratios (HRs) for disease progression (defined as development of a ≥ 30% decline in eGFR or end-stage renal disease) using a Cox proportional hazard model.

RESULTS

Median extent of proteinuria reduction was -2.1, -0.9, and -0.2 g/gCr in the first, second, and third tertiles, respectively. There were concomitant changes in the slopes of annual eGFR decline: -2.03, -2.44, and -4.62 mL/min/1.73 m2 among the first, second, and third tertiles, respectively. In multivariable Cox analysis, the HRs (95% confidence intervals) for disease progression were 0.30 (0.12 to 0.74) in the first tertile and 0.70 (0.34 to 1.45) in the second tertile compared with the thirdtertile.

CONCLUSION

This study showed that greater proteinuria reduction after immunosuppression was associated with a lower risk of disease progression in patients with IgAN, suggesting that responsiveness to immunosuppression may be an important determinant of kidney outcomes.

Association Between Longitudinal Blood Pressure Trajectory and the Progression of Chronic Kidney Disease: Results From the KNOW-CKD

Studies on the longitudinal temporal trend of blood pressure (BP) and its impact on kidney function are scarce. Here, we evaluated the association of dynamic changes in systolic blood pressure (SBP) over time with adverse kidney outcomes. We analyzed 1837 participants from the KNOW-CKD (Korean Cohort Study for Outcomes in Patients With Chronic Kidney Disease). The main exposure was 3 distinct SBP trajectories determined by the latent class mixed model (decreasing, stable, and increasing) using 3 SBP measurements at 0, 6, and 12 months. The primary outcome was CKD progression, defined as a composite of halving estimated glomerular filtration rate from baseline value or onset of end-stage kidney disease. SBP declined from 144 to 120 mm Hg in the decreasing SBP trajectory group and rose from 114 to 136 mm Hg in the increasing trajectory group within 1 year. During 6576 person-years of follow-up (median, 3.7 years), the composite outcome occurred in 521 (28.4%) participants. There were fewer primary outcome events in the decreasing (30.6%) and stable (26.5%) SBP trajectory groups than in the increasing trajectory group (33.0%). In the multivariable-adjusted cause-specific hazards model, increasing SBP trajectory was associated with a 1.28-fold higher risk for adverse kidney outcome compared with stable SBP trajectory. However, the risk for the primary outcome did not differ between the decreasing and stable SBP trajectory groups. In this longitudinal CKD cohort study, compared with stable SBP trajectory, increasing SBP trajectory was associated with higher risk for adverse kidney outcome, whereas decreasing SBP trajectory showed similar risk.

Inflammation Alters Relationship Between High-Density Lipoprotein Cholesterol and Cardiovascular Risk in Patients With Chronic Kidney Disease: Results From KNOW-CKD

Background

The function of high‐density lipoprotein can change from protective to proatherosclerotic under inflammatory conditions. Herein, we studied whether inflammation could modify the relationship between high‐density lipoprotein level and risk of adverse outcomes in patients with chronic kidney disease .

Methods and Results

In total, 1864 patients from the prospective KNOW‐CKD (Korean Cohort Study for Outcome in Patients With Chronic Kidney Disease) were enrolled. The main predictor was high‐density lipoprotein cholesterol (HDL‐C) level. Presence of inflammation was defined by hs‐CRP (high‐sensitivity C‐reactive protein) level of ≥1.0 mg/L. The primary outcome was extended major adverse cardiovascular events. During 9231.2 person‐years of follow‐up, overall incidence of the primary outcome was 15.8 per 1000 person‐years. In multivariable Cox analysis after adjusting for confounders, HDL‐C level was not associated with the primary outcome. There was a significant interaction between the inflammatory status and HDL‐C for risk of extended major adverse cardiovascular events (P=0.003). In patients without inflammation, the hazard ratios (HRs) (95% CIs) for HDL‐C levels <40, 50 to 59, and ≥60 mg/dL were 1.10 (0.50–1.82), 0.95 (0.50–1.82), and 0.42 (0.19–0.95), respectively, compared with HDL‐C of 40 to 49 mg/dL. However, the significant association for HDL‐C ≥60 mg/dL was not seen after Bonferroni correction. In patients with inflammation, we observed a trend toward increased risk of extended major adverse cardiovascular events in higher HDL‐C groups (HRs [95% CIs], 0.73 [0.37–1.43], 1.24 [0.59–2.61], and 1.56 [0.71–3.45], respectively), but without statistical significance.

Conclusions

The association between HDL‐C level and adverse cardiovascular outcomes showed reverse trends based on inflammation status in Korean patients with chronic kidney disease.

Registration

URL: https://www.clinicaltrials.gov; Unique identifier: NCT01630486.

Mixed versus predilution hemodiafiltration effects on convection volume and small and middle molecule clearance in hemodialysis patients: a prospective randomized controlled trial

Background

The use of newly developed mixed-dilution hemodiafiltration (HDF) can supplement the weaknesses of pre- and postdilution HDF. However, it is unclear whether mixed-HDF performs well compared to predilution HDF.

Methods

We conducted a prospective, open-labeled, randomized controlled trial from two hemodialysis centers in Korea. Between January 2017 and September 2019, 60 patients who underwent chronic hemodialysis were randomly assigned at a 1:1 ratio to receive either predilution HDF (n = 30) or mixed-HDF (n = 30) for 6 months. We compared convection volume, changes in small- and medium-sized molecule clearance, high-sensitive C-reactive protein (hs-CRP) level, and dialysis-related parameters between the two dialysis modalities.

Results

A mean effective convection volume of 41.0 ± 10.3 L/session in the predilution HDF group and 51.5 ± 9.0 L/session in the mixed-HDF group was obtained by averaging values of three time-points. The difference in effective convection volume between the groups was 10.5 ± 1.3 L/session. This met the preset noninferiority criteria, suggesting that mixed-HDF was noninferior to predilution HDF. Moreover, the β2-microglobulin reduction rate was greater in the mixed-HDF group than in the predilution HDF group, while mixed-HDF provided greater transmembrane pressure. There were no significant between-group differences in Kt/V urea levels, changes in predialysis hs-CRP levels, proportions of overhydration, or blood pressure values. Symptomatic intradialytic hypotension episodes and other adverse events occurred similarly in the two groups.

Conclusion

Use of mixed-HDF was comparable to predilution HDF in terms of delivered convection volume and clinical parameters. Moreover, mixed-HDF provided better β2-microglobulin clearance than predilution HDF.

Increased risk of acute kidney injury in coronavirus disease patients with renin-angiotensin-aldosterone-system blockade use: a systematic review and meta-analysis

Acute kidney injury (AKI) is a severe complication of coronavirus disease (COVID-19) that negatively affects its outcome. Concern had been raised about the potential effect of renin-angiotensin-aldosterone system (RAAS) blockades on renal outcomes in COVID-19 patients. However, the association between RAAS blockade use and incident AKI in COVID-19 patients has not been fully understood. We investigated the association between RAAS blockade exposure and COVID-19-related AKI in hospitalized patients through meta-analysis. Electronic databases were searched up to 24th December 2020. Summary estimates of pooled odds ratio (OR) of COVID-19-related AKI depending on RAAS blockade exposure were obtained through random-effects model. The random-effect meta-analysis on fourteen studies (17,876 patients) showed that RAAS blockade use was significantly associated with increased risk of incident AKI in hospitalized COVID-19 patients (OR 1.68; 95% confidence interval 1.19-2.36). Additional analysis showed that the association of RAAS blockade use on COVID-19-related AKI remains significant even after stratification by drug class and AKI severity. RAAS blockade use is significantly associated with the incident AKI in hospitalized COVID-19 patients. Therefore, careful monitoring of renal complications is recommended for COVID-19 patients with recent RAAS blockade use due to the potential risk of AKI.

Urinary chloride concentration and progression of chronic kidney disease: results from the KoreaN cohort study for Outcomes in patients With Chronic Kidney Disease

BACKGROUND

Urinary chloride is regulated by kidney transport channels, and high urinary chloride concentration in the distal tubules can trigger tubuloglomerular feedback. However, little attention has been paid to urinary chloride as a biomarker of clinical outcomes. Here, we studied the relationship between urinary chloride concentration and chronic kidney disease (CKD) progression.

METHODS

We included 2086 participants with CKD from the KoreaN cohort study for Outcomes in patients With Chronic Kidney Disease. Patients were categorized into three groups, according to baseline urinary chloride concentration tertiles. The study endpoint was a composite of ≥50% decrease in estimated glomerular filtration rate from baseline values, or end-stage kidney disease.

RESULTS

During a median follow-up period of 3.4 years (7452 person-years), 565 participants reached the primary endpoint. There was a higher rate of CKD progression events in the lowest and middle tertiles than in the highest tertile. Compared with the lowest tertile, the highest tertile was associated with 33% [95% confidence interval (CI) 0.49-0.90] lower risk for the primary outcome in a cause-specific hazard model after adjustment for confounding variables. In addition, for every 25 mEq/L increase in urinary chloride concentration, there was 11% (95% CI 0.83-0.96) lower risk for CKD progression. This association was consistent in a time-varying model. Urinary chloride concentration correlated well with tubule function and kidney injury markers, and its predictive performance for CKD progression was comparable to that of these markers.

CONCLUSIONS

In this hypothesis-generating study, low urinary chloride concentration was associated with a higher risk for CKD progression.

Smoking Cessation and Coronary Artery Calcification in CKD

BACKGROUND AND OBJECTIVES

Smoking is associated with vascular calcification and a higher risk of cardiovascular disease. In this study, we investigated the association of smoking dose and cessation with coronary artery calcification (CAC) in patients with CKD.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

From a nationwide, prospective cohort of Korean patients with CKD, 1914 participants were included. Prevalent CAC was defined as an Agatston score >0, using computed tomography. CAC progression was defined as ≥30%/yr increase in Agatston score at the 4-year follow-up examination in patients with baseline CAC.

RESULTS

Prevalent CAC was observed in 952 (50%) patients. Compared with never smokers, former smokers had a similar prevalence ratio for CAC, but current smokers had a 1.25-fold higher prevalence ratio (95% confidence interval [95% CI], 1.10 to 1.42). Among former smokers, a lower smoking load of <10 pack-years (prevalence ratio, 0.77; 95% CI, 0.65 to 0.90) and longer duration of smoking cessation (prevalence ratio for 10 to <20 years, 0.85; 95% CI, 0.73 to 0.98: prevalence ratio for ≥20 years, 0.83; 95% CI, 0.73 to 0.96) were associated with lower risk of prevalent CAC compared with current smoking. The prevalence ratios did not differ between never smoking and long-term cessation. However, short-term cessation with heavy smoking load was associated with a higher risk of prevalent CAC (prevalence ratio, 1.21; 95% CI, 1.03 to 1.40) compared with never smoking. CAC progression was observed in 111 (33%) patients with baseline CAC. Compared with never smokers, former smokers showed a similar risk of CAC progression, but current smokers had a higher risk (relative risk, 1.92; 95% CI, 1.30 to 2.86).

CONCLUSIONS

In CKD, former smoking with a lower smoking load and long-term cessation were associated with a lower risk of prevalent CAC than current smoking. CAC progression was more pronounced in current smokers.

Exosome-based delivery of super-repressor IκBα ameliorates kidney ischemia-reperfusion injury

Ischemia-reperfusion injury is a major cause of acute kidney injury. Recent studies on the pathophysiology of ischemia-reperfusion-induced acute kidney injury showed that immunologic responses significantly affect kidney ischemia-reperfusion injury and repair. Nuclear factor (NF)-ĸB signaling, which controls cytokine production and cell survival, is significantly involved in ischemia-reperfusion-induced acute kidney injury, and its inhibition can ameliorate ischemic acute kidney injury. Using EXPLOR, a novel, optogenetically engineered exosome technology, we successfully delivered the exosomal super-repressor inhibitor of NF-ĸB (Exo-srIĸB) into B6 wild type mice before/after kidney ischemia-reperfusion surgery, and compared outcomes with those of a control exosome (Exo-Naïve)-injected group. Exo-srIĸB treatment resulted in lower levels of serum blood urea nitrogen, creatinine, and neutrophil gelatinase-associated lipocalin in post-ischemic mice than in the Exo-Naïve treatment group. Systemic delivery of Exo-srIĸB decreased NF-ĸB activity in post-ischemic kidneys and reduced apoptosis. Post-ischemic kidneys showed decreased gene expression of pro-inflammatory cytokines and adhesion molecules with Exo-srIĸB treatment as compared with the control. Intravital imaging confirmed the uptake of exosomes in neutrophils and macrophages. Exo-srIĸB treatment also significantly affected post-ischemic kidney immune cell populations, lowering neutrophil, monocyte/macrophage, and T cell frequencies than those in the control. Thus, modulation of NF-ĸB signaling through exosomal delivery can be used as a novel therapeutic method for ischemia-reperfusion-induced acute kidney injury.

Glomerular subepithelial microparticles - a footprint for podocyte injury

The aim of this study was to clarify the nature and clinical significance of glomerular subepithelial microparticles (SMPs), located between the basal surface of the podocytes and the glomerular basement membrane. Ultrastructural morphology of 79 renal biopsy samples (obtained from 25 native and 54 transplanted kidneys), showing SMPs in the last 3 years, was reevaluated with regard to the podocyte changes and clinical condition of the patients. One hundred and nine SMPs were identified, with 32.9% of the samples having two or more per glomerulus. Overall, they were most frequently located in the open capillary loops (55%). However, in the native kidney samples with mesangial deposits, 64.3% of SMPs were present in the mesangium-bound areas. Each vesicle ranged from 46.9 to 87.1 nm, and vesicles were admixed with curved strands in larger SMPs. Diffuse effacement of the foot processes and condensation of the actin filaments were present in 56.0% and 62.4% of the samples, respectively. SMPs were associated with hematuria, proteinuria of ≥ 1 gm, and immune complex deposition in the patients with native kidneys, whereas they were related to hyperglycemia and elevated serum creatinine levels in the patients with renal allografts. Patients with native and transplanted kidneys most commonly presented with IgA nephropathy and allograft rejection, respectively. Finding SMPs in the renal biopsy samples is not rare and they may act as a footprint of podocyte injury caused by diverse etiologies. Considering their size, podocyte exosomes could be a possible source of SMPs.

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.