Kidney Research and Clinical Practice最新文献

Background: Constipation is a common gastrointestinal disorder and is often accompanied by alteration in the gut microbiota. Recently, several studies have disclosed its association with an increased risk of cardiovascular disease and mortality in the general population. Despite the high prevalence of constipation, data on the clinical impact of constipation in patients with chronic kidney disease are limited. We aimed to explore the prevalence of constipation and its association with cardiovascular disease in chronic kidney disease using a nationally representative cohort of hemodialysis patients.

Methods: This study used hemodialysis quality assessment and health insurance claims data from patients undergoing maintenance hemodialysis in South Korea. Chronic constipation was defined using the total number of laxatives prescribed during the 1-year baseline period. The primary outcome was a composite of acute ischemic stroke, hemorrhagic stroke, myocardial infarction, or all-cause death. Secondary outcomes were the individual components of the primary outcome.

Results: Among 35,230 patients on hemodialysis, 9,133 (25.9%) were identified as having constipation. During a median follow-up of 5.4 years, patients with constipation had a 15% higher incidence of the composite outcome, 16% higher incidence of ischemic stroke, and 14% higher all-cause mortality, after multivariate adjustment.

Conclusion: Chronic constipation requiring laxatives was associated with a higher risk of the composite outcome of cardiovascular events or all-cause death in patients on hemodialysis. Further studies are needed to confirm whether constipation is an independent predictor or a possible causal factor of cardiovascular disease.

Background: The prevalence of end-stage renal disease (ESRD) requiring dialysis has progressively increased. Therefore, to achieve financial stability by managing the increasing numbers of patients undergoing hemodialysis (HD), a fixed-payment system was introduced in 2001 for medical aid (MA) beneficiaries receiving HD in Korea.

Methods: We identified patients in the Korean Renal Data System that received HD between 2001 and 2017 and stratified them into the following two groups: the National Health Insurance (NHI) and MA groups. Then, we compared the two groups that differed in demographic characteristics, the treatment process and outcomes, and mortality based on health insurance type.

Results: Among 52,574 patients, the number of patients aged 65 years or older, hypertension was higher in the NHI group, but diabetes was higher in the MA group. Additionally, the MA group had more weekly dialysis sessions, and expensive drugs tended to be used less frequently. Regarding treatment outcomes, including laboratory test results, the MA group achieved significantly lower goals than the NHI group (p < 0.001). Furthermore, the mortality rate per 1,000 persons was 31 and 27 in the MA and NHI groups, respectively, and the mortality rate ratio was 1.2 (95% confidence interval [CI], 1.076-1.230). Moreover, the hazard ratio for mortality was 1.39 (95% CI, 1.30-1.49, p < 0.001) after adjusting for age, sex, causes of ESRD, and comorbidities.

Conclusion: There were significant differences in the treatment and mortality indicators between the groups. Therefore, policy support should be strengthened to provide better medical services to MA beneficiaries undergoing HD.

Background: In patients with type 2 diabetes mellitus (T2DM), diabetic kidney disease (DKD) is diagnosed based on clinical features. A kidney biopsy is used only in selected cases. This study aimed to reconsider the role of a biopsy in predicting renal outcomes.

Methods: Clinical and laboratory parameters and renal biopsy results were obtained from 237 patients with T2DM who underwent renal biopsies at Soonchunhyang University Cheonan Hospital between January 2000 and March 2020 and were analyzed.

Results: Of 237 diabetic patients, 29.1% had DKD only, 61.6% had non-DKD (NDKD), and 9.3% had DKD with coexisting NDKD (DKD/NDKD). Of the patients with DKD alone, 43.5% progressed to end-stage kidney disease (ESKD), while 15.8% of NDKD patients and 36.4% of DKD/NDKD patients progressed to ESKD (p < 0.001). In the DKD-alone group, pathologic features like ≥50% global sclerosis (p < 0.001), tubular atrophy (p < 0.001), interstitial fibrosis (p < 0.001), interstitial inflammation (p < 0.001), and the presence of hyalinosis (p = 0.03) were related to worse renal outcomes. The Cox regression model showed a higher risk of progression to ESKD in the DKD/NDKD group compared to the DKD-alone group (hazard ratio [HR], 2.73; p = 0.032), ≥50% global sclerosis (HR, 3.88; p < 0.001), and the degree of mesangial expansion (moderate: HR, 2.45; p = 0.045 and severe: HR, 6.22; p < 0.001).

Conclusion: In patients with T2DM, a kidney biopsy can help in identifying patients with NDKD for appropriate treatment, and it has predictive value.

Background: Although the introduction of erythropoietin-stimulating agents (ESAs) has led to better clinical outcomes in patients undergoing hemodialysis (HD), fluctuations in hemoglobin (Hb) levels, known as Hb variability, are frequently observed. However, only a few studies have evaluated the association between Hb variability and nutritional status in patients undergoing HD.

Methods: In this prospective study conducted between March 1, 2020, and June 1, 2022, we included 109 patients aged over 20 years undergoing HD and receiving darbepoetin. We checked the average NESP (darbepoetin-alfa; Kyowa Kirin Korea Co., Ltd.) dose weekly and nutritional parameters such as body mass index (BMI), fat tissue index (FTI), and lean tissue index obtained by body composition monitoring. Additionally, the ESA resistance index (ERI) and the coefficient of variation of Hb (Hb-CV) were evaluated.

Results: In this study, the mean age of the patients was 64.0 ± 11.9 years, and 55.0% were male. Mean Hb was 10.7 ± 1.3 g/dL. Patients were categorized into three groups according to the ERI or Hb-CV tertiles. The highest ERI tertile was associated with lower Hb levels, BMI, and FTI. The highest Hb-CV tertile was associated with lower BMI and FTI. In multiple linear regression analysis, FTI was negatively associated with ERI (β = -0.218, p = 0.01) and Hb-CV (β = -0.181, p = 0.04).

Conclusion: These findings suggest that FTI is negatively associated with ERI and Hb-CV, and that ESAs responsiveness and Hb variability are associated with FTI in patients undergoing HD with darbepoetin treatment.

Extracellular vesicles (EVs) are nanosized membranous particles released by nearly all cell types, playing a crucial role in mediating cell-to-cell communication. The molecular profile of EVs often reflects that of their originating cells, rendering them valuable for therapeutic and diagnostic purposes. The kidney comprises various cell types, and urinary EVs are predominantly produced from tubular, glomerular, and urinary bladder cells. Within the nephron, EVs produced from the upper segments, such as glomerular tufts and proximal tubules, can be taken up by their downstream counterparts, thereby altering the physiology of recipient cells. Recent studies have demonstrated that this proximal-distal intra-nephron crosstalk via EVs is crucial for normal kidney physiology. Additionally, EVs from interstitial cells (e.g., fibroblasts and macrophages) have been demonstrated to mediate the exacerbation of kidney damage. This review provides up-to-date findings on the function of renal EVs during the progression of renal diseases. Furthermore, we discussed future directions to use the clinical potential of renal EVs as an early biomarker for renal disorders.

Background: Membranoproliferative glomerulonephritis (MPGN) has two subtypes based on immunofluorescence findings: complement 3 glomerulopathy (C3G) and immune complex-mediated MPGN (IC-MPGN). This study investigated the characteristics and prognosis of patients with MPGN.

Methods: This retrospective study analyzed data from 18 hospitals between 1979 and 2018. Among 21,697 patients, 620 were diagnosed with MPGN, 570 with IC-MPGN, and 50 with C3G.

Results: The C3G group had a lower estimated glomerular filtration rate (eGFR; 49.9 ± 40.7 mL/min/1.73 m2 vs. 62.7 ± 36.5 mL/min/1.73 m2, p = 0.02) compared with the IC-MPGN group. This trend continued at 6 months: patients with reduced renal function were 36.7% in the C3G group (p = 0.11). However, the IC-MPGN group had significantly higher levels of proteinuria (4.7 ± 4.2 g/g vs. 2.9 ± 2.6 g/g, p < 0.001). The 50.7% of patients with IC-MPGN had nephrotic-range proteinuria. Serum C3 levels were significantly lower in the C3G group (p = 0.04). Hepatitis B surface antigen positivity was significantly more frequent in the IC-MPGN group (35.3% vs. 7.0%, p < 0.001). Interstitial fibrosis and tubular atrophy, markers of chronic kidney damage, were more prevalent in the IC-MPGN group (p ≤ 0.001). During a follow-up period of 122.4 ± 124.2 months, a total of 159 patients (27.7%) with MPGN progressed to end-stage kidney disease (ESKD): 151 IC-MPGN (28.4%) and eight C3G patients (19.0%) (p = 0.28). The adjusted risk of 40% eGFR decline, ESKD, and mortality was not different between groups.

Conclusion: The C3G group initially showed severe renal dysfunction. Despite having fewer chronic histological findings, the long-term renal outcomes for C3G remained as unfavorable as those for IC-MPGN. This suggests that C3G may require careful monitoring and treatment.

Background: Obstructive sleep apnea (OSA) is a sleep disorder associated with an increased risk of cardiovascular and metabolic complications. Albuminuria, an early marker of kidney damage, is a proposed risk factor for OSA and its adverse outcomes. The study explored the association between OSA and albuminuria in Korean adults.

Methods: We screened participants from the cross-sectional Korean National Health and Nutrition Examination Survey (2019- 2021). The study included participants aged 40 years and older who completed the STOP-BANG questionnaire, a tool used to assess the OSA risk. Albuminuria was defined as a urine albumin-to-creatinine ratio ≥30 mg/g Cr. The participants were categorized based on albuminuria presence and severity. A multivariate logistic regression analysis examined the association between albuminuria and OSA.

Results: This study included 10,923 participants. Participants with albuminuria had significantly higher STOP-BANG scores than those without. Moreover, albuminuria remained strongly associated with an increased risk of OSA (odds ratio, 2.01; 95% confidence interval, 1.66-2.43), after multivariate adjustment. This association was more pronounced as albuminuria severity increased. Participants with high STOP-BANG scores were more likely to have albuminuria (odds ratio, 2.51; 95% confidence interval, 1.89-3.31), highlighting the bidirectional relationship between albuminuria and OSA.

Conclusion: The present study demonstrated a significant association between albuminuria and an elevated risk of OSA. These findings underscore the importance of early screening for OSA in patients with albuminuria, particularly in those with additional metabolic risk factors, to improve their long-term outcomes.

Background: Lupus nephritis is well-known for low concordance in classification. Furthermore, there has been no agreement analysis among Korean renal pathologists regarding lupus nephritis. Inconsistent diagnosis leads to confusion and increases medical costs, as well as failure of appropriate therapeutic interventions. This study aimed to assess the level of agreement among Korean renal pathologists regarding classification.

Methods: Representative glomerular images from patients diagnosed with lupus nephritis were obtained from five hospitals. Twenty-five questions were formulated, and multiple-choice questions with 14 options, consisting of characteristic histopathological findings of lupus nephritis were provided. Three rounds of surveys were conducted and educational sessions were conducted before the second and third surveys.

Results: The agreement was calculated using Fleiss' κ and the means for each round of questions were as follows: Survey 1, 0.42 (range, 0.18-0.61), Survey 2, 0.42 (range, 0.19-0.64), and Survey 3, 0.47 (range, 0.23-0.65). Although κ after the first education session showed no significant difference compared to the initial κ (p = 0.95), after the second education session, κ increased significantly compared to the initial κ (p < 0.001). The κ for each item generally increased with each education session, but they were not statistically significant (p = 0.46, p = 0.17). Additionally, the rankings of agreement, for each item, were relatively consistent.

Conclusion: This study conducted an interobserver agreement analysis of Korean pathologists for lupus nephritis, with the goal of increasing agreement through education. Although the education increased overall agreement, items like "mesangial hypercellularity," "endocapillary hypercellularity," and "neutrophils and/or karyorrhexis" remained inconsistent attributable to innate subjectivity and ineffective education.

Background: Light chain amyloidosis, characterized by amyloid fibril deposition in multiple organs, often leads to progression to endstage kidney disease. This study aimed to identify predictors of kidney survival in patients with kidney amyloidosis, focusing on hematologic and kidney response.

Methods: This retrospective study included 138 patients diagnosed with kidney amyloidosis between 2011 and 2019. Palladini criteria were applied to categorize kidney stage and kidney response based on initial glomerular filtration rate and proteinuria, and their changes after treatment. Hematologic response was assessed based on the 2012 International Society of Amyloidosis criteria. Deep hematologic response was defined as the achievement of at least a very good partial response.

Results: Overall, 17 (12.3%) progressed to end-stage kidney disease. Multivariable analysis, considering baseline characteristics, revealed that stage II had an increased risk of end-stage kidney disease compared to stage I (hazard ratio, 3.75; 95% confidence interval [CI], 1.38-10.15; p = 0.01). Compared to kidney response, the risk of end-stage kidney disease increased by 8.42 (95% CI, 1.72-41.35; p = 0.01) and 7.36 (95% CI, 1.25-43.33; p = 0.03) times in stable disease and kidney progression at 6 months, respectively, whereas deep hematologic response showed no association with kidney outcome. Kidney survival was longer in patients with deep hematologic response and kidney response than in those with only hematologic response (p = 0.004).

Conclusion: The study underscores the importance of kidney response over hematologic response in predicting end-stage kidney disease and emphasizes the need to assess treatment endpoints, considering organ response alongside hematologic response.

Background: Nutcracker syndrome (NCS) has been reported to coexist with various glomerulonephritis (GN). This study investigated clinical features of NCS combined with GN in a pediatric case series and the possible relationship between these two conditions.

Methods: Clinical and pathologic findings of 15 children with NCS and biopsy-proven GN were analyzed. NCS was diagnosed with renal Doppler ultrasonography, abdominal computed tomography, and/or magnetic resonance imaging. Glomerular lesions were divided into two pathological categories: minor glomerular abnormalities (MGAs) and definite GN.

Results: Mean age of all patients was 11 ± 3.36 years and mean follow-up duration was 53.8 ± 29.3 months. Chief complaint was proteinuria with or without hematuria. During follow-up, five patients developed left kidney enlargement. Abnormal levels in immunological tests were revealed in 10 patients. Extrarenal symptoms including gonadal varicocele, splenic cyst, syncope, and anemia were found in seven patients. On kidney biopsy, seven patients had MGAs and eight children showed definite GN (one case of focal GN, one case of mesangial proliferative GN, one case of focal segmental glomerulosclerosis, two cases of immunoglobulin A [IgA] vasculitis nephritis, and three cases of IgA nephropathy). While the MGA group showed a higher proportion of isolated proteinuria and a lower estimated glomerular filtration rate (eGFR) at the last visit, there were no differences in age, clinical features of NCS, extrarenal symptoms, immunological tests, and eGFR decline rate between the two groups.

Conclusion: NCS may be associated with the presence of various GN. The causal relationship between NCS and GN should be further investigated.