BACKGROUND: The target blood pressure (BP) value is unclear for diabetic kidney disease (DKD). Therefore, we aimed to evaluate the effect of strict BP control or \'on treatment\' BP on clinical outcomes in patients with DKD.
METHODS: A post-hoc analysis of the prespecified secondary outcomes of the FimAsartaN proTeinuriA SusTaIned reduCtion in comparison with losartan in diabetic chronic kidney disease (FANTASTIC) trial, a randomized multicenter double-blind phase III trial. Eligible patients were aged ≥ 19 years with DKD. We assigned 341 participants with DKD to BP control strategy (standard-systolic BP [SBP] < 140 mmHg versus strict-SBP < 130 mmHg). The outcome was the occurrence of cardiovascular events and renal events. Separate analyses were performed to compared the risk of outcome according to achieved average BP levels.
RESULTS: A total of 341 participants were included in the analysis. Over a median follow-up of 2.8 years, cardiovascular/renal events were observed in 25 (7.3%) participants. Mean (SD) SBPs in the standard and strict BP control group were 140.2 (11.6) and 140.2 (11.9) mmHg, respectively. The strict BP control group did not show significantly reduced risk of cardiovascular/renal events (HR 1.32; 95% CI 0.60-2.92]). In the post-hoc analyses using achieved BP, achieved average SBP of 130-139 mmHg resulted in reduced risk of cardiovascular/renal events (HR 0.15; 95% CI 0.03-0.67) compared to achieved average SBP ≥ 140 mmHg, whereas further reduction in achieved average SBP < 130 mmHg did not impart additional benefits.
CONCLUSIONS: In patients with DKD, targeting a SBP of less than 130 mmHg, as compared with less than 140 mmHg, did not reduce the rate of a composite of cardiovascular and renal events. Achieved SBP of 130-139 mmHg was associated with a decreased risk for the primary outcome in patients with DKD.
BACKGROUND: ClinicalTirals.gov Identifier: NCT02620306, registered December 3, 2015. ( https://clinicaltrials.gov/study/NCT02620306 ).

Glomerulomegaly and focal segmental glomerulosclerosis are histopathological hallmarks of obesity-related glomerulopathy (ORG). Podocyte injury and subsequent depletion are regarded as key processes in the development of these glomerular lesions in patients with ORG, but their impact on long-term kidney outcome is undetermined. Here, we correlated clinicopathological findings and podocyte depletion retrospectively in patients with ORG. Relative (podocyte density) and absolute (podocyte number per glomerulus) measures of podocyte depletion were estimated using model-based stereology in 46 patients with ORG. The combined endpoint of kidney outcomes was defined as a 30% decline in estimated glomerular filtration rate (eGFR) or kidney failure. Patients with lower podocyte density were predominantly male and had larger body surface area, greater proteinuria, fewer non-sclerotic glomeruli, larger glomeruli and higher single-nephron eGFR. During a median follow-up of 4.1 years, 18 (39%) patients reached endpoint. Kidney survival in patients with lower podocyte density was significantly worse than in patients with higher podocyte density. However, there was no difference in kidney survival between patient groups based on podocyte number per glomerulus. Cox hazard analysis showed that podocyte density, but not podocyte number per glomerulus, was associated with the kidney outcomes after adjustment for clinicopathological confounders. Thus, our study demonstrates that a relative depletion of podocytes better predicts long-term kidney outcomes than does absolute depletion of podocytes. Hence, the findings implicate mismatch between glomerular enlargement and podocyte number as a crucial determinant of disease progression in ORG.

BACKGROUND: The effects of tonsillectomy combined with steroid pulse (TSP) therapy for IgA nephropathy (IgAN) are little known. Therefore, we examined the effects of TSP therapy on the kidney outcomes of IgAN in a large, nationwide cohort study in Japan.
METHODS: Between 2002 and 2004, 632 IgAN patients with ≥ 0.5 g/day proteinuria at diagnosis were divided into three groups with mild (0.50-0.99 g/day; n = 264), moderate (1.00-1.99 g/day, n = 216), or severe (≥ 2.00 g/day; n = 153). Decline in kidney function and urinary remission were compared among the three groups after TSP therapy, corticosteroid (ST) therapy, or conservative therapy during a mean follow-up of 6.2 ± 3.3 years. 10.6% and 5.9% of patients in the ST and conservative therapy group underwent tonsillectomy.
RESULTS: The rate of urinary remission at the final observation was significantly higher in the TSP therapy group than in the ST or conservative therapy groups (mild proteinuria: 64%, 43%, and 41%; moderate proteinuria: 51%, 45%, and 28%; severe proteinuria: 48%, 30%, and 22%, respectively). In contrast, the rate of a 50% increase in serum creatinine was lower in groups TSP therapy, than ST or conservative therapy (mild proteinuria: 2.1%, 10.1% and 16.7%; moderate proteinuria: 4.8%, 8.8% and 27.7%; severe proteinuria: 12.0%, 28.9% and 43.1%, respectively). In multivariate analysis, TSP therapy significantly prevented a 50% increase in serum creatinine levels compared with conservative therapy in groups with moderate and severe proteinuria (hazard ratio, 0.12 and 0.22, respectively).
CONCLUSIONS: TSP significantly increased the rate of proteinuria disappearance and urinary remission in IgAN patients with mild-to-moderate urinary protein levels. It may also reduce the decline in kidney function in patients with moderate-to-severe urinary protein levels.

BACKGROUND: Type 2 diabetes (T2D) is the major contributor to chronic kidney disease and end-stage kidney disease (ESKD). The influence of trimethylamine N-oxide (TMAO) on kidney outcomes in T2D remains unclear.
OBJECTIVE: To examine the association between fasting serum TMAO levels and adverse kidney outcomes in patients with T2D.
METHODS: Between October 2016 and June 2020, patients with T2D were recruited and monitored every 3 months until December 2021. Serum TMAO levels were assessed using liquid chromatography-mass spectrometry. The primary kidney outcomes were doubling of serum creatinine levels or progression to ESKD necessitating dialysis; the secondary kidney outcome was a rapid 30% decline in estimated glomerular filtration rate within 2 years. All-cause mortality was also evaluated.
RESULTS: Among the 440 enrolled patients with T2D, those in the highest serum TMAO tertile (≥0.88 μM) were older, had a longer diabetes duration, elevated blood urea nitrogen, and lower estimated glomerular filtration rate. Over a median follow-up period of 4 years, 26 patients (5.9%) had a doubling of serum creatinine level or progression to ESKD. After propensity score weighting, the patients in the highest serum TMAO tertile had a 6.45-fold increase in the risk of doubling of serum creatinine levels or progression to ESKD and 5.86-fold elevated risk of rapid decline in kidney function compared with those in the lowest tertile. Additionally, the stepwise increase in serum TMAO was associated with all-cause mortality.
CONCLUSIONS: Patients with T2D with elevated circulating TMAO levels are at higher risk of doubling serum creatinine, progressing to ESKD, and mortality. TMAO is a potential biomarker for kidney function progression and mortality in patients with T2D.

BACKGROUND: Serum activin A has been reported to contribute to vascular calcification and kidney fibrosis in chronic kidney disease. We aimed to investigate whether higher serum activin levels were associated with poor allograft outcomes in patients with kidney transplantation (KT).
METHODS: A total of 860 KT patients from KNOW-KT (Korean Cohort Study for Outcome in Patients with Kidney Transplantation) were analyzed. We measured serum activin levels pre-KT and 1 year after KT. The primary outcome was the composite of a ≥50% decline in estimated glomerular filtration rate and graft failure. Multivariable cause-specific hazard model was used to analyze association of 1-year activin levels with the primary outcome. The secondary outcome was coronary artery calcification score (CACS) at 5 years after KT.
RESULTS: During the median follow-up of 6.7 years, the primary outcome occurred in 109 (12.7%) patients. The serum activin levels at 1 year were significantly lower than those at pre-KT (488.2 ± 247.3 vs. 704.0 ± 349.6). When patients were grouped based on the median activin level at 1 year, the high-activin group had a 1.91-fold higher risk (95% CI, 1.25-2.91) for the primary outcome compared to the low-activin group. A one-standard deviation increase in activin levels as a continuous variable was associated with a 1.36-fold higher risk (95% CI, 1.16-1.60) for the primary outcome. Moreover, high activin levels were significantly associated with 1.56-fold higher CACS (95% CI, 1.12-2.18).
CONCLUSIONS: Post-transplant activin levels were independently associated with allograft functions as well as coronary artery calcification in KT patients.

OBJECTIVE: To perform dose-exposure-response analyses to determine the effects of finerenone doses.
METHODS: Two randomized, double-blind, placebo-controlled phase 3 trials enrolling 13 026 randomized participants with type 2 diabetes (T2D) from global sites, each with an estimated glomerular filtration rate (eGFR) of 25 to 90 mL/min/1.73 m2 , a urine albumin-creatinine ratio (UACR) of 30 to 5000 mg/g, and serum potassium ≤ 4.8 mmol/L were included. Interventions were titrated doses of finerenone 10 or 20 mg versus placebo on top of standard of care. The outcomes were trajectories of plasma finerenone and serum potassium concentrations, UACR, eGFR and kidney composite outcomes, assessed using nonlinear mixed-effects population pharmacokinetic (PK)/pharmacodynamic (PD) and parametric time-to-event models.
RESULTS: For potassium, lower serum levels and lower rates of hyperkalaemia were associated with higher doses of finerenone 20 mg compared to 10 mg (p < 0.001). The PK/PD model analysis linked this observed inverse association to potassium-guided dose titration. Simulations of a hypothetical trial with constant finerenone doses revealed a shallow but increasing exposure-potassium response relationship. Similarly, increasing finerenone exposures led to less than dose-proportional increasing reductions in modelled UACR. Modelled UACR explained 95% of finerenone\'s treatment effect in slowing chronic eGFR decline. No UACR-independent finerenone effects were identified. Neither sodium-glucose cotransporter-2 (SGLT2) inhibitor nor glucagon-like peptide-1 receptor agonist (GLP-1RA) treatment significantly modified the effects of finerenone in reducing UACR and eGFR decline. Modelled eGFR explained 87% of finerenone\'s treatment effect on kidney outcomes. No eGFR-independent effects were identified.
CONCLUSIONS: The analyses provide strong evidence for the effectiveness of finerenone dose titration in controlling serum potassium elevations. UACR and eGFR are predictive of kidney outcomes during finerenone treatment. Finerenone\'s kidney efficacy is independent of concomitant use of SGLT2 inhibitors and GLP-1RAs.

BACKGROUND: Studies on kidney function and histological findings in diabetic nephropathy (DN) with low urinary protein (UP) are few. We examined the differential impact of histological changes on kidney outcomes between non-proteinuric and proteinuric DN.
METHODS: Patients diagnosed with DN by renal biopsy during 1981-2014 were divided into non-proteinuric (UP ≤ 0.5 g/day) and proteinuric (UP > 0.5 g/day) DN. The Cox proportional hazard model was used to examine the association of glomerular lesions (GLs) and interstitial fibrosis and tubular atrophy (IFTA) with end-stage kidney disease (ESKD) development after adjusting for relevant confounders.
RESULTS: The non-proteinuric and proteinuric DN groups included 197 and 199 patients, respectively. During the 10.7-year median follow-up period, 16 and 83 patients developed ESKD in the non-proteinuric and proteinuric DN groups, respectively. In the multivariable Cox hazard model, hazard ratios (HRs) [95% confidence intervals (CIs)] of GL and IFTA for ESKD in proteinuric DN were 2.94 [1.67-5.36] and 3.82 [2.06-7.53], respectively. Meanwhile, HRs [95% CIs] of GL and IFTA in non-proteinuric DN were < 0.01 [0-2.48] and 4.98 [1.33-18.0], respectively. IFTA was consistently associated with higher incidences of ESKD regardless of proteinuria levels (P for interaction = 0.49). The prognostic impact of GLs on ESKD was significantly decreased as proteinuria levels decreased (P for interaction < 0.01).
CONCLUSIONS: IFTA is consistently a useful predictor of kidney prognosis in both non-proteinuric and proteinuric DN, while GLs are a significant predictor of kidney prognosis only in proteinuric DN.

OBJECTIVE: Tumor necrosis factor (TNF) receptors (TNFRs: TNFR1 and, TNFR2) are reportedly associated with chronic kidney disease (CKD) progression chiefly in Caucasian patients with diabetes. We assessed the prognostic value of TNF-related biomarkers for CKD progression in Japanese patients with diabetes.
METHODS: We estimated TNF-related biomarkers using an enzyme-linked immunosorbent assay in 640 patients with diabetes. Cox proportional hazards analysis was performed to estimate hazard ratios (HRs) per one standard deviation (SD) increase in a log-transformed biomarker. The kidney and the composite outcome were defined as a 30% reduction in estimated glomerular filtration rate (eGFR) from baseline, and kidney outcome plus death before kidney outcome, respectively.
RESULTS: During the median follow-up of 5.4 years, 75 (11.7%) patients reached the kidney outcome and 37 (5.8%) died before reaching the kidney outcome. Each SD increase in baseline circulating TNFR1, TNFR2, and ephrin type-A receptor 2 (EphA2) was associated with a higher risk of the kidney outcome independently from baseline eGFR and urine albumin-to-creatinine ratio. However, circulating osteoprotegerin was associated with the composite outcome only.
CONCLUSIONS: Elevated TNFR1, TNFR2, and EphA2 were associated with both kidney and composite outcomes in Japanese patients with diabetes.

Sodium-glucose cotransporter 2 inhibitors (SGLT2i) have a favorable impact on the kidney function in patients with heart failure (HF), while there is no clear evidence of what factors predict this effect. The aim of the study was to identify plausible predictors for kidney function outcome among patients with HF and investigate their association with SGLT2i.
We prospectively enrolled 480 patients with type 2 diabetes mellitus (T2DM) treated with diet and metformin and concomitant chronic HF and followed them for 52 weeks. In the study, we determined kidney outcome as a composite of ≥ 40% reduced estimated glomerular filtration rate from baseline, newly diagnosed end-stage kidney disease or kidney replacement therapy. The relevant medical information and measurement of the biomarkers (N-terminal natriuretic pro-peptide, irisin, apelin, adropin, C-reactive protein, tumor necrosis factor-alpha) were collected at baseline and at the end of the study.
The composite kidney outcome was detected in 88 (18.3%) patients of the entire population. All patients received guideline-recommended optimal therapy, which was adjusted to phenotype/severity of HF, cardiovascular risk and comorbidity profiles, and fasting glycemia. Levels of irisin, adropin and apelin significantly increased in patients without clinical endpoint, whereas in those with composite endpoint the biomarker levels exhibited a decrease with borderline statistical significance (p = 0.05). We noticed that irisin ≤ 4.50 ng/ml at baseline and a ≤ 15% increase in irisin serum levels added more valuable predictive information than the reference variable. However, the combination of irisin ≤ 4.50 ng/ml at baseline and ≤ 15% increase in irisin serum levels (area under curve = 0.91; 95% confidence interval = 0.87-0.95) improved the discriminative value of each biomarker alone.
We suggest that low levels of irisin and its inadequate increase during administration of SGLT2i are promising predictors for unfavorable kidney outcome among patients with T2DM and concomitant HF.

BACKGROUND: Proteinuria remission is the most significant predictive factor for kidney outcome in childhood IgA nephropathy (c-IgAN). Even if proteinuria remission can be obtained, some patients have recurrence of proteinuria in the long-term.
METHODS: This is a retrospective analysis of 312 cases of proteinuria remission among 538 consecutive children with biopsy-proven IgAN from 1976 to 2013. To elucidate the incidence and factors related to recurrence of proteinuria in c-IgAN, we compare clinical and pathological findings between patients with and without recurrence of proteinuria.
RESULTS: Among 312 patients with remission of proteinuria, 91 (29.2%) had recurrence of proteinuria within the observation period (median 8 years). Using a multivariate Cox regression analysis, significant factors associated with recurrence of proteinuria were onset age (HR 1.13 [95%CI: 1.05-1.22], P = 0.002) and presence of hematuria after proteinuria remission (HR 2.11 [95%CI: 1.30-3.45], P = 0.003). The Kaplan-Meier analysis showed significant differences in CKD G3a-G5-free survival between the patients with no-recurrence of proteinuria, recurrence of proteinuria and non-proteinuria remission (P < 0.0001, log-rank test). Kidney survival was 100% in no-recurrence of proteinuria, 92.2% in recurrence of proteinuria, and 65.6% in non-proteinuria remission at 15 years. Cox analyses adjusted by proteinuria remission showed that recurrence of proteinuria (HR 03.10e9 [95%CI: NA], P = 0.003) was a significant factor associated with progression to CKD G3a-G5 in all patients with c-IgAN.
CONCLUSIONS: Approximately 30% of patients with proteinuria remission had recurrence of proteinuria regardless of treatment. Both remission and recurrence of proteinuria are significant prognostic factors for kidney outcome. A higher resolution version of the Graphical abstract is available as Supplementary information.