Kidney Research and Clinical Practice最新文献

Background: Posttransplantation diabetes mellitus (PTDM) is a crucial problem after kidney transplantation. We aimed to determine whether metformin affects cardiovascular and graft outcomes in patients with PTDM.

Methods: This retrospective cohort study included 1,663 kidney transplant recipients without preexisting diabetes mellitus. The patients were divided into metformin and non-metformin groups, with matched propensity scores. We also estimated metformin's effect on percutaneous coronary intervention (PCI), major adverse cardiovascular events (MACEs), acute rejection, and graft failure.

Results: Of 634 recipients with PTDM, 406 recipients were treated with metformin. The incidence of PCI was 2.4% and 7.1% in the metformin and non-metformin groups, respectively (p = 0.04). The metformin group exhibited a lower risk of PCI in Cox regression analyses (hazard ratio [HR], 0.27; 95% confidence interval [CI], 0.10-0.77; p = 0.014), especially in subgroups with male sex, age over 49 years (median), long-term metformin use (mean of ≥1,729 days), and simultaneous tacrolimus administration. Long-term metformin use was also associated with lower incidence of MACEs (HR, 0.09; 95% CI, 0.01-0.67; p = 0.02). Incidence of graft failure was 9.9% and 17.0% in the metformin and non-metformin groups, respectively (p = 0.046). Both long-term use and higher dose of metformin, as well as tacrolimus administration with metformin, were associated with a lower risk of graft failure (HR, 0.29; 95% CI, 0.11-0.75; p = 0.01; HR, 0.39; 95% CI, 0.18-0.85; p = 0.02; and HR, 0.39; 95% CI, 0.19-0.79; p = 0.009, respectively).

Conclusion: Metformin use is associated with a decreased risk of developing coronary artery disease and better graft outcomes in PTDM.

Background: The optimal timing of continuous renal replacement therapy (CRRT) initiation in acute kidney injury (AKI) remains uncertain, particularly regarding long-term kidney outcomes. This study evaluated whether early CRRT initiation improves the risk of acute kidney disease (AKD) or death.

Methods: In this multicenter retrospective cohort, 852 patients with baseline creatinine ≤4 mg/dL who received CRRT at eight tertiary hospitals were screened. Early initiation was defined as starting CRRT before KDIGO stage 3 or before severe oliguria (<0.3 mL/ kg/hr for 24 hours). Propensity score matching (1:1) based on demographic, clinical, and laboratory variables yielded 746 matched patients. The primary outcome was a composite of AKD (≥50% increase in serum creatinine from baseline at 3 months) or death before 3-month follow-up. Multivariable logistic regression and stratified analyses by median baseline creatinine were performed.

Results: Early CRRT was associated with a significantly lower incidence of the composite outcome (odds ratio [OR], 0.40; 95% confidence interval [CI], 0.28-0.57; p < 0.001). The protective effect persisted in both the low-creatinine (OR, 0.46; 95% CI, 0.29-0.72) and high-creatinine subgroups (OR, 0.38; 95% CI, 0.21-0.68). A significant interaction between early CRRT and baseline creatinine (p = 0.04) suggested that the magnitude of benefit associated with early CRRT varied according to baseline renal function. Early CRRT was not significantly associated with 90-day mortality alone (adjusted OR, 0.69; p = 0.27).

Conclusion: Early CRRT initiation was associated with improved kidney-related outcomes, particularly in patients with lower baseline renal function. These findings support a more individualized approach to CRRT timing based on baseline kidney function.

Background: Vascular access failure is a major cause of morbidity in hemodialysis patients, primarily driven by smooth muscle cell (SMC) proliferation-related neointimal hyperplasia. The uremic toxin p-cresyl sulfate (p-CS) has been linked to poor vascular access outcomes, but its pathogenic mechanisms remain unclear. This study investigated whether p-CS promotes SMC proliferation and induces endothelial dysfunction, and contributes to neointimal hyperplasia.

Methods: Human aortic SMCs were treated with p-CS to assess proliferation and activation of ERK1/2 and p38 MAPK signaling. In human umbilical vein endothelial cells (HUVECs), oxidative stress and expression of inflammatory mediators (NF-κB, ICAM-1, MCP-1) were measured at mRNA and protein levels, along with eNOS and iNOS expression. A Transwell co-culture system was used to evaluate whether p-CS-induced endothelial alterations affect SMC proliferation. Neointimal formation after p-CS exposure was confirmed using an ex vivo mouse aorta model.

Results: p-CS promoted SMC proliferation in a dose-dependent manner and activated ERK1/2 and p38 MAPK. In HUVECs, p-CS induced ROS generation and increased NF-κB, ICAM-1, and MCP-1 expression, while upregulating iNOS and suppressing eNOS. In co-culture, p-CS-stimulated HUVECs enhanced SMC proliferation; this effect was attenuated by NAC, probenecid, or neutralizing antibodies against MCP-1 and ICAM-1. In the ex vivo aorta model, p-CS induced neointimal hyperplasia accompanied by elevated α-SMA, ICAM-1, and MCP-1 expression.

Conclusion: These findings suggest that p-CS may promote SMC proliferation both directly and indirectly through endothelial dysfunction, ultimately contributing to neointimal hyperplasia. Further studies are needed to clarify the clinical implications of p-CS in vascular access dysfunction.

Medical nutrition therapy serves as the cornerstone in the management of chronic kidney disease (CKD). While conventional approaches emphasize macronutrient restriction and meal timing adjustments, research highlights the critical mediating role of gut microbiota in translating dietary patterns into physiological effects through metabolite production. Meanwhile, CKD progression is closely associated with dynamic interactions between gut microbiota and their metabolic derivatives. This review introduces the "diet-microbiota- metabolite-kidney axis" framework to elucidate how nutritional components modulate CKD progression via microbial compositional changes and subsequent metabolite alterations. Based on synthesized evidence, this review identifies promising directions for precision nutrition strategies targeting microbial metabolites, including artificial intelligence-assisted dietary planning, engineered bacterial therapies, and metabolite analog development. However, significant interindividual variability in host genetics and baseline microbiota composition necessitates overcoming heterogeneity challenges in nutritional interventions. Consequently, the precise modulation of individualized diet-microbiota-metabolite interactions represents a critical research direction to be prioritized in CKD management.

Background: Catheter-related infections, such as exit-site infection and tunnel infection, are major complications in peritoneal dialysis (PD) patients, affecting their prognosis. This study investigates the association between skin conditions and catheter-related infections.

Methods: Data from two distinct sources were analyzed: (1) 626 PD patients in the Korean arm of the Peritoneal Dialysis Outcomes and Practice Patterns Study (PDOPPS) and (2) skin microbiome data from 76 dialysis patients at Soonchunhyang University Cheonan Hospital. The relationship between catheter-related infection and self-reported xerosis and pruritus severity was assessed by Cox regression. Risk factors for xerosis and pruritus were evaluated by logistic regression. Furthermore, we discovered the relationship between the severity of pruritus and the relative abundance of Staphylococcus aureus on the skin.

Results: The risk of catheter-related infections in PD patients increased with xerosis (hazard ratio [HR], 2.71; 95% confidence interval [CI], 1.19-6.18) and pruritus (HR, 2.57; 95% CI, 1.27-5.22), particularly increasing the risk of S. aureus-associated catheter-related infections (xerosis: HR, 5.66; 95% CI, 1.97-16.30; pruritus: HR, 5.93; 95% CI, 2.18-16.15). The relative abundance of S. aureus was notably higher in patients with severe pruritus. Moreover, patients were more likely to exhibit severe xerosis if they owned pets, had higher serum creatinine levels, and elevated calcium-phosphorus product levels.

Conclusion: Xerosis and pruritus significantly increase the risk of catheter-related infections, especially those caused by S. aureus. Instead of relying solely on prophylactic antibiotics for infection prevention, this study highlights the need for new preventive strategies in PD patients, focusing specifically on effective skin management.

Background: Evidence remains limited regarding the association between cardiovascular health (CVH), as defined by Life's Essential 8 (LE8), and chronic kidney disease (CKD), particularly across its indicators and stages.

Methods: We analyzed data from 12,264 adults in the Korea National Health and Nutrition Examination Survey (2019-2021). LE8 scores (range, 0-100), calculated from eight components-diet, physical activity, nicotine exposure, sleep, body mass index, blood lipids, blood glucose, and blood pressure, were analyzed as both continuous and categorical variables: low (0 to <50), moderate (50 to <80), and high CVH (80 to 100). CKD was defined as an estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m2 or albuminuria (urine albumin-to-creatinine ratio ≥30 mg/g). Multivariable logistic regression and restricted cubic spline models were used to examine associations between LE8 scores and CKD, with stratification by CKD indicators and by G and A stages.

Results: Overall, 13.3% of participants were classified as having low CVH, 75.4% as moderate CVH, and 11.3% as high CVH. Compared to low CVH, the odds of CKD were lower in moderate CVH (odds ratio [OR], 0.39; 95% confidence interval [CI], 0.33-0.46) and high CVH (OR, 0.22; 95% CI, 0.15-0.33). Each 10-point higher CVH score was associated with 33% lower odds of CKD (OR, 0.67; 95% CI, 0.63-0.71). After stratifying decreased eGFR and albuminuria by G and A stages, higher CVH was consistently associated with lower odds of CKD, even for early stages.

Conclusion: Higher LE8 scores were inversely associated with CKD and its indicators, including early-stage CKD.

The prevalence of chronic kidney disease (CKD) in Asia was determined by comparing differences in age, sex, area, and analytical methods. This meta-analysis comprised 42 studies with 2,271,169 participants from five databases that were searched until February 30, 2025. The total prevalence of CKD 1-5 was 17.0%, whereas that of stages 3-5 was 7.7% in Asia. Individuals aged >60 years had a higher prevalence rate of CKD 1-5 compared to those aged <60 years. Compared with Asia (as the comparator), the age-standardized prevalence of CKD (aCKD) 1-5 was the highest in Nepal and South Asia, whereas it was the lowest in Vietnam. Compared with the comparator, Vietnam and Malaysia had the highest aCKD 3-5; while, South Korea and India had lower aCKD 3-5. The sex-standardized prevalence of CKD (sCKD) 1-5 was lower in Nepal, Taiwan, Korea, and South Asia and was higher in Bangladesh than in the comparator. The sCKD 3-5 was lowest in Korea and Taiwan and was highest in Iran and Sri Lanka compared with the comparator. Iranian women and men had the highest prevalence of CKD 3-5. South Asia has a higher prevalence of CKD among men and women than East Asia. The prevalence of CKD was greater in the Chronic Kidney Disease Epidemiology Collaboration-based studies than in the Modification of Diet in Renal Disease (MDRD)-based research. The findings indicate that evaluating populations without considering sex and age is difficult, especially when the sex and age of the groups differ greatly.

Background: Functional impairments in elderly patients with chronic kidney disease may affect prognosis. This study evaluated the associations between activities of daily living (ADL), instrumental activities of daily living (IADL), renal replacement therapy (RRT), and mortality.

Methods: We retrospectively analyzed 6,087 adults aged ≥65 years (2,737 men and 3,350 women) who underwent geriatric assessment at Seoul National University Bundang Hospital from 2016 to 2020. All had an estimated glomerular filtration rate (eGFR) >15 mL/min/1.73 m2 and were followed for more than 3 months. ADL and IADL were measured using the Barthel and Lawton-Brody Index, and analyses were stratified by sex due to differences in IADL scoring criteria.

Results: Participants (mean age, 78.7 ± 6.0 years; eGFR, 75.8 ± 19.4 mL/min/1.73 m2) were followed for a median of 42 months; 2,108 (34.6%) died and 103 (1.7%) initiated RRT. Impaired ADL and IADL were significantly associated with increased mortality in both sexes. In men, IADL impairment (<5) predicted RRT, whereas ADL (<100) showed a weaker association (p = 0.05). In women, neither ADL (<100) nor IADL (<8) significantly predicted RRT.

Conclusion: Functional impairments independently predicted mortality in both sexes and were associated with a higher risk of RRT in men, particularly among younger individuals or those with preserved renal function. ADL and IADL assessments may provide practical indicators for identifying high-risk elderly patients with early-stage kidney disease.

Background: Triglyceride-glucose index (TyGi), a surrogate marker of metabolic dysfunction, has not been evaluated for kidney outcomes in patients with metabolic dysfunction-associated fatty liver disease (MAFLD). We aimed to evaluate this association in individuals with MAFLD.

Methods: Totally 868 patients with MAFLD from the Gangnam Severance Medical Cohort (2006-2021) were included. TyGi trajectories were defined using latent class mixture modeling based on their longitudinal changes: decreasing (n = 426) vs. increasing (n = 442). MAFLD was diagnosed based on hepatic steatosis and at least one of the following: overweight or obese, type 2 diabetes, or two or more metabolic abnormalities. Kidney outcomes included: sustained reduction in eGFR to <60 mL/min/1.73 m2 for those with baseline eGFR of ≥60 mL/min/1.73 m2, ≥30% decline from baseline for those with eGFR <60 mL/min/1.73 m2, or initiation of dialysis or kidney transplantation. Cause-specific Cox proportional hazard models assessed the association between TyGi trajectories and kidney outcomes.

Results: The participants' mean age was 52.3 ± 10.4 years and 504 (58.1%) were male. Over a median follow-up of 6.9 years (4.0- 10.0 years), 36 kidney outcome events occurred. The incidence rates were 4.02 and 9.06 per 1,000 person-years in the decreasing and increasing TyGi trajectory groups, respectively (p = 0.02). In a multivariable cause-specific Cox model, the increasing trajectory group had a significantly greater risk of kidney outcomes than the decreasing group (hazard ratio, 3.68; 95% confidence interval, 1.68- 8.05; p = 0.001). Subgroup analyses showed consistent findings.

Conclusion: Increasing longitudinal TyGi levels are associated with a higher risk of adverse kidney outcomes in patients with MAFLD.

Background: The impact of early hemoglobin levels following kidney transplantation (KT) on long-term outcomes remains unclear. This study evaluates the association between early posttransplant hemoglobin levels and clinical outcomes.

Methods: A total of 7,501 kidney transplant recipients (KTRs) from a nationwide cohort were included. Hemoglobin levels at 6 months post-KT were analyzed. KTRs were categorized into five hemoglobin groups: <10, 10 to <11, 11 to <12, 12 to <13 (reference group), and ≥13 g/dL. The primary outcome was a composite of cardiovascular events, graft loss, and all-cause mortality. Multivariable Cox regression was employed to assess the relationship between hemoglobin levels and the composite outcome.

Results: The cohort had a mean age of 49.6 ± 11.6 years, and 60.4% were male. The incidence of the composite outcome and its individual components was highest among KTRs with hemoglobin levels <10 g/dL. Hemoglobin levels <10 g/dL were associated with a significantly increased risk of the composite outcome (hazard ratio [HR], 3.16; 95% confidence interval [CI], 2.05-4.87; p < 0.001) and were identified as an independent risk factor for each component. Conversely, hemoglobin levels ≥13 g/dL were associated with improved survival (HR, 0.44; 95% CI, 0.22-0.90; p = 0.02). Subgroup analyses confirmed that hemoglobin levels <10 g/ dL consistently increased the risk of the composite outcome.

Conclusion: Posttransplant anemia with hemoglobin levels <10 g/dL showed a significant association with an increased risk of the composite outcome. Conversely, hemoglobin levels ≥13 g/dL were linked to better patient survival.