Clinical and Experimental Nephrology最新文献

Background: We previously reported an association between cnm-positive Streptococcus mutans in the oral cavity and IgA nephropathy. However, whether this association is specific to IgA nephropathy among various kidney diseases remains unclear. This study aimed to investigate the presence of cnm-positive S. mutans in patients who underwent a renal biopsy and to evaluate its association with different kidney disease subtypes.

Methods: We included 294 patients who underwent a renal biopsy and provided informed consent between May 2017 and March 2024 (renal biopsy group). The healthy control group consisted of 81 individuals with an estimated glomerular filtration rate > 60 mL/min and no proteinuria. Saliva samples were collected from all participants, stored at - 20 °C, and analyzed by polymerase chain reaction to detect S. mutans and cnm-positive S. mutans. Associations between cnm-positive S. mutans and the histopathological diagnosis were subsequently assessed.

Results: The prevalence of cnm-positive S. mutans was significantly higher in the renal biopsy group than in the control group (21.8% vs. 11.1%, p < 0.05). Among kidney disease subtypes in the renal biopsy group, a higher prevalence of cnm-positive S. mutans was observed in patients with lupus nephritis (31.6%), membranous nephropathy (29.2%), and IgA nephropathy (23.6%). However, a logistic regression analysis identified a significant association only between cnm-positive S. mutans and IgA nephropathy (p < 0.05).

Conclusion: This study suggests that cnm-positive S. mutans is significantly associated with IgA nephropathy.

Background: This study aimed to evaluate the associations between cardiovascular health (CVH) scores, measured by Life's Simple 7 (LS7), Life's Essential 8 (LE8), and Life's Crucial 9 (LC9), and the risks of all-cause and cardio-cerebrovascular disease (CCD) mortality among individuals with chronic kidney disease (CKD).

Methods: Data from 4,989 adults with CKD in the National Health and Nutrition Examination Survey (NHANES) 2005-2018 were analyzed. Cox proportional hazards regression models assessed associations between CVH metrics and mortality risks. Predictive performance was evaluated using receiver operating characteristic (ROC) curves and area under the curve (AUC) values at 3-, 5-, and 10 year follow-ups.

Results: During a median follow-up of 6.2 years, higher CVH scores across all metrics were associated with significantly lower risks of all-cause and CCD mortality. Higher CVH scores were significantly associated with lower risks of all-cause and CCD mortality. For all-cause mortality, participants with the highest LS7 scores (≥ 11) had a 71% lower risk (HR = 0.29, 95% CI: 0.18-0.46) compared to those with the lowest scores (≤ 4). Similarly, participants with the highest LE8 (> 79.9) and LC9 (> 79.9) scores had a 69% and 73% lower risk of all-cause mortality, respectively.

Conclusions: LS7, LE8, and LC9 showed similar discrimination for all-cause and CCD mortality. Adding sleep and psychological health components did not meaningfully improve risk discrimination beyond LS7 in adults with CKD, supporting LS7 as a practical tool for mortality risk stratification.

Clinical nephrology research is increasingly challenged by the need to translate complex patient experiences, emerging biomarkers and treatments, and an expanding methodological tools into improvements in care. Clinical epidemiology provides a bridge between bedside questions and population science; however, its role is often narrowly perceived as clinical statistics rather than as a discipline centered on research conceptualization and design. In this invited review, I reflect on how clinical questions arising from routine nephrology practice can be systematically developed into clinically relevant research through a nephrologist-epidemiologist's lens. First, drawing on our experience and illustrative examples, I describe how rethinking care processes through established frameworks-such as the structure-process-outcome model-can support clinicians in formulating answerable questions that matter to patients. Second, I expand the lens beyond traditional nephrology to incorporate perspectives from social medicine, emphasizing trust, hope, and patient-reported outcomes as integral components of chronic kidney disease care. Finally, this review highlights how clinical questions can be embedded within clinical research design frameworks to clarify research objectives across diagnosis, treatment, prognosis, and etiology. In an era of rapid methodological diversification, the nephrologist-epidemiologist's unique contribution may lie in cultivating a sharpened lens: the ability to discern relevant clinical questions and sustain deep clinical reasoning. By doing so, clinical epidemiology can continue to guide research that advances comprehensive and patient-centered kidney care.

Background: Zinc deficiency is widely recognized as a cause of anemia, but no studies have clarified the impact of zinc deficiency on achieving target hemoglobin levels in patients undergoing peritoneal dialysis (PD) and receiving high-dose erythropoiesis-stimulating agent (ESA) therapy. This study aimed to investigate the relationship between zinc deficiency and ESA-hyporesponsive anemia in patients on PD.

Methods: This cross-sectional study included 164 patients on PD aged ≥ 18 years. The target hemoglobin level was 11-13 g/dL. ESA dosage was categorized as low-dose (< 120 µg/month) or high-dose (≥ 120 µg/month), while zinc deficiency was defined as a serum zinc level < 60 µg/dL. A logistic regression model was used to calculate the odds ratio (OR) for achieving the target hemoglobin level.

Results: The proportion of patients achieving the target hemoglobin level was 48.2% in the low-dose ESA and non-zinc-deficient group, and 12.2% in the high-dose ESA and zinc-deficient group. Compared with the low-dose ESA and non-zinc-deficient group, the adjusted OR for achieving the target hemoglobin level was significantly lower in the high-dose ESA and zinc-deficient group (OR: 0.19, 95% confidence interval 0.05-0.72). Stratified analyses based on serum albumin, serum C-reactive protein, and transferrin saturation did not change the association between the high-dose ESA and zinc-deficient group and the achievement of the target hemoglobin level.

Conclusion: Zinc deficiency in patients on PD is a significant barrier to achieving the target hemoglobin level, and serum zinc levels should be routinely monitored in patients with ESA-hyporesponsive anemia.

Background: The increasing number of dialysis patients presents a significant public health challenge in Japan. While the number of patients initiating dialysis due to chronic glomerulonephritis (CGN) or diabetic kidney disease (DKD) has decreased, the incidence of dialysis initiation attributed to nephrosclerosis has gradually increased. To investigate regional differences, Hokkaido, Japan, was selected as one regional example in this study.

Methods: Data were extracted from a web-based national database for patients aged ≥ 40 years who initiated dialysis between 2012 and 2021. Patients were categorized according to sex, age, and underlying disease. Dialysis initiation rates were calculated as the number of new dialysis patients divided by the corresponding population. To assess temporal changes, the 2021/2016 ratio was calculated by dividing the initiation rate in 2021 by that in 2016 for each prefecture.

Results: In Hokkaido, the dialysis initiation rates for DKD declined across all age groups, whereas the national rate increased in men aged ≥ 80 years. For nephrosclerosis, the initiation rates rose among older adults both nationally and in Hokkaido, although the increase in Hokkaido was more gradual. CGN-related rates decreased consistently across all age groups, both nationally and in Hokkaido. Prefectures with 2021/2016 ratio of ≥ 1 were more frequently observed among patients with nephrosclerosis than among those with CGN or DKD, especially among older populations.

Conclusions: Dialysis initiation rates in Hokkaido decreased in most subgroups compared with national trends. Given the rising incidence of nephrosclerosis among older adults, targeted interventions at the prefectural level are urgently warranted.

Background: IgA nephropathy (IgAN) is increasingly recognized as a complication of inflammatory bowel disease (IBD), particularly Crohn's disease (CD). Recent studies suggest that mucosal immune dysregulation and biologic therapies, particularly tumor necrosis factor (TNF)-α inhibitors, may influence the onset and progression of IgAN in IBD. However, its clinicopathological characteristics in this context remain uncertain.

Methods: We conducted a retrospective, multicenter study of patients with biopsy-proven IgAN and concurrent CD. Patients with CD-associated IgAN (CD-IgAN) were compared with those with ulcerative colitis-associated IgAN (UC-IgAN) and with IgAN unassociated with IBD (non-IBD-IgAN). Clinical parameters at kidney biopsy, treatment history, and histopathological findings were evaluated. One-year outcomes included changes in proteinuria, hematuria status, and estimated glomerular filtration rate (eGFR).

Results: In total, eight patients with CD-IgAN, eight patients with UC-IgAN, and 32 matched non-IBD-IgAN controls were included. Patients with CD-IgAN exhibited lower eGFR, higher serum IgA levels, and a higher prevalence of tubulointerstitial nephritis compared to non-IBD-IgAN controls. Moreover, CD-IgAN was characterized by significantly lower eGFR and a nonsignificant trend toward more advanced tubulointerstitial injury compared to UC-IgAN. The use of TNF-α inhibitors was more frequent in the CD-IgAN group. At 1 year, all groups exhibited reductions in proteinuria, with no significant differences in eGFR change or hematuria resolution.

Conclusions: CD-IgAN represents a distinct clinicopathological phenotype characterized by lower kidney function and more severe tubulointerstitial injury. Although causality cannot be inferred, careful kidney monitoring should be considered in patients with CD, particularly those receiving TNF-α inhibitors.

Introduction: Sodium-glucose cotransporter 2 inhibitors (SGLT2i) and glucagon-like peptide 1 receptor agonists (GLP-1Ra) have shown renoprotective effects in type 2 diabetes (T2D). Our previous findings suggested superior renal outcomes with SGLT2i compared to GLP-1Ra, particularly due to greater reductions in blood pressure (BP). However, whether this benefit extends to obese patients remains unclear. This study compared renal outcomes between SGLT2i and GLP-1Ra in obese Japanese patients with T2D.

Methods: This retrospective study included patients with T2D and body mass index ≥ 25 kg/m² treated with either SGLT2i (n = 439) or GLP-1Ra (n = 174) for over one year. Patients receiving both drugs were excluded. The renal composite outcome was defined as an annual decline in estimated glomerular filtration rate (eGFR) > 30%, progression of albuminuria category, or both. Propensity score matching was applied to balance baseline characteristics.

Results: After matching (n = 89 per group), the incidence of renal events did not differ significantly between the two groups. The annual decline in eGFR tended to be smaller with SGLT2i than with GLP-1Ra (- 1.6 ± 3.5 vs. - 2.8 ± 5.8 mL/min/1.73 m²/year, p = 0.13). SGLT2i-treated patients also showed greater reductions in systolic BP and body weight (BW) (- 5.0 ± 19.7 vs. - 1.1 ± 18.0 mmHg, p = 0.19; - 3.3 ± 4.6 vs. - 1.9 ± 4.9 kg, p = 0.05, respectively).

Conclusion: Among this population, the annual eGFR decline appeared numerically smaller with SGLT2i-tretament, without statistical significance. Greater BP and BW reductions were observed, though their impact on renal outcomes remains uncertain.

Background: The beneficial effects of physical activity (PA) on cardiovascular disease and its risk factors have been well established. However, evidence linking PA to chronic kidney disease (CKD) in patients with diabetes is limited. This study aimed to examine the association between PA, including leisure-time PA (LTPA) and daily life PA (DLPA), and CKD cross-sectionally.

Methods: A total of 4,922 patients with type 2 diabetes were classified into quartiles of LTPA and three categories of DLPA (sedentary, light, and moderate/vigorous). CKD was defined as a decreased estimated glomerular filtration rate (eGFR) based on cystatin C (< 60 mL/min/1.73 m²) and/or albuminuria (urinary albumin-to-creatinine ratio ≥ 30 mg/g). Odds ratios for the presence of CKD were computed using logistic regression analyses.

Results: Higher LTPA levels were significantly associated with a lower likelihood of developing CKD (P for trend = 0.001). Higher DLPA was also associated with a lower prevalence of CKD (P for trend < 0.001). Similar associations were observed for decreased eGFR and albuminuria. The combination of higher LTPA and DLPA levels further decreased the likelihood of CKD, with a significant interaction between the two.

Conclusions: Higher LTPA and DLPA levels were independently associated with a lower prevalence of CKD in patients with type 2 diabetes.

Background: There have been no clear recommendations regarding the optimal timing, setting, content, and duration for peritoneal dialysis (PD) education. This nationwide survey aimed to examine current PD educational practices across Japanese facilities and explore factors associated with the incidence of PD-related peritonitis.

Methods: Eligible facilities were institutional members of the Japanese Society for Peritoneal Dialysis. The questionnaire consisted of five sections covering facility characteristics, facility-level peritonitis profiles, PD education, peritonitis prophylaxis, and re-education. Associations between PD practices and the incidence of PD-related peritonitis were examined using linear and logistic regression analyses.

Results: A total of 194 facilities were included between November 2024 and May 2025. The median peritonitis incidence rates in 2023 and 2024 were 0.18 and 0.20 episodes/patient-year, respectively. Regression analyses showed that an annual training frequency of two or more sessions for education staff, earlier initiation of PD education (before catheter insertion vs. around PD initiation), more frequent visits during the first month after PD initiation (once every 1-2 weeks vs. once every 3-4 weeks), and routine patient re-education were associated with lower incidence of peritonitis or higher achievement of the target incidence rate of < 0.4 episodes/patient-year.

Conclusions: Regular training for patient educators, early initiation of patient education before catheter insertion, and follow-up with re-education after PD initiation were associated with lower rates of PD-related peritonitis.

Background: Long-term transitions in physical function among patients receiving hemodialysis remain poorly characterised. We aimed to describe 8-year trajectories of physical function and examine their associations with baseline dialysis duration and physical function status.

Methods: This nationwide cohort study analysed data from 223,501 Japanese adults undergoing hemodialysis registered in the 2010 Japanese Society for Dialysis Therapy Renal Data Registry. Baseline dialysis duration was categorised as < 5, 5- < 10, 10- < 20, 20- < 30, or ≥ 30 years. Physical function at baseline was assessed using the Eastern Cooperative Oncology Group Performance Status and classified as non-frail, frail, or bedridden. Physical function at 8 years was categorised as non-frail, frail, bedridden, or deceased. Multinomial logistic regression estimated adjusted odds ratios, average marginal effects, and predicted probabilities.

Results: Over 8 years, 59.9% died, 8.8% became frail, 2.4% were bedridden, and 28.9% remained non-frail. Longer dialysis duration and baseline frailty or bedridden status were associated with higher odds of subsequent frailty, bedridden status, and mortality. Compared with patients with < 5 years of dialysis, those with ≥ 30 years had a 1.6% higher probability of frailty and a 13.2% higher probability of death. Compared with baseline non-frail status, frailty was associated with a 0.04% change in frailty and a 15.8% increase in death; bedridden status was associated with a 1.7% increase in being bedridden and a 26.0% increase in death.

Conclusions: Long-term dialysis duration and baseline physical function strongly influence mortality, whereas absolute frailty progression is modest. These findings support early, values-based shared decision-making in dialysis care.