Defining the threshold: triglyceride to high-density lipoprotein cholesterol (TG/HDL-C) ratio's non-linear impact on tubular atrophy in primary membranous nephropathy.

Background: Hyperlipidemia is common in primary membranous nephropathy (PMN) patients, and tubular atrophy (TA) is an unfavorable prognostic factor. However, the correlation between the triglyceride to high-density lipoprotein cholesterol (TG/HDL-C) ratio and TA is controversial. Therefore, our study aimed to investigate the association between the TG/HDL-C ratio and TA in PMN patients. Methods: We conducted a cross-sectional study and collected data from 363 PMN patients at Shenzhen Second People's Hospital from January 2008 to April 2023. The primary objective was to evaluate the independent correlation between the TG/HDL-C ratio and TA using binary logistic regression model. We used a generalized additive model along with smooth curve fitting and multiple sensitivity analyses to explore the relationship between these variables. Additionally, subgroup analyses were conducted to delve deeper into the results. Results: Of the 363 PMN patients, 75 had TA (20.66%). The study population had a mean age of 46.598 ± 14.462 years, with 217 (59.78%) being male. After adjusting for sex, age, BMI, hypertension, history of diabetes, smoking, alcohol consumption, UPRO, eGFR, HB, FPG, and ALB, we found that the TG/HDL-C ratio was an independent risk factor for TA in PMN patients (OR=1.29, 95% CI: 1.04, 1.61, P=0.0213). A non-linear correlation was observed between the TG/HDL-C ratio and TA, with an inflection point at 4.25. The odds ratios (OR) on the left and right sides of this inflection point were 1.56 (95% CI: 1.17, 2.07) and 0.25 (95% CI: 0.04, 1.54), respectively. Sensitivity analysis confirmed these results. Subgroup analysis showed a consistent association between the TG/HDL-C ratio and TA, implying that factors such as gender, BMI, age, UPRO, ALB, hypertension and severe nephrotic syndrome had negligible effects on the link between the TG/HDL-C ratio and TA. Conclusion: Our study demonstrates a non-linear positive correlation between the TG/HDL-C ratio and the risk of TA in PMN patients, independent of other factors. Specifically, the association is more pronounced when the ratio falls below 4.25. Based on our findings, it would be advisable to decrease the TG/HDL-C ratio below the inflection point in PMN patients as part of treatment strategies.

Incidence, risk factors and outcome of postoperative acute kidney injury in China.

BACKGROUND: Postoperative acute kidney injury (AKI) is a common condition after surgery, however, the available data about nationwide epidemiology of postoperative AKI in China from large and high-quality studies are limited. This study aimed to determine the incidence, risk factors and outcomes of postoperative AKI among patients undergoing surgery in China. METHODS: This was a large, multicentre, retrospective study performed in 16 tertiary medical centres in China. Adult patients (≥18 years of age) who underwent surgical procedures from 1 January 2013 to 31 December 2019 were included. Postoperative AKI was defined by the Kidney Disease: Improving Global Outcomes creatinine criteria. The associations of AKI and in-hospital outcomes were investigated using logistic regression models adjusted for potential confounders. RESULTS: Among 520 707 patients included in our study, 25 830 (5.0%) patients developed postoperative AKI. The incidence of postoperative AKI varied by surgery type, which was highest in cardiac (34.6%), urologic (8.7%) and general (4.2%) surgeries. A total of 89.2% of postoperative AKI cases were detected in the first 2 postoperative days. However, only 584 (2.3%) patients with postoperative AKI were diagnosed with AKI on discharge. Risk factors for postoperative AKI included older age, male sex, lower baseline kidney function, pre-surgery hospital stay ≤3 days or >7 days, hypertension, diabetes mellitus and use of proton pump inhibitors or diuretics. The risk of in-hospital death increased with the stage of AKI. In addition, patients with postoperative AKI had longer lengths of hospital stay (12 versus 19 days) and were more likely to require intensive care unit care (13.1% versus 45.0%) and renal replacement therapy (0.4% versus 7.7%). CONCLUSIONS: Postoperative AKI was common across surgery type in China, particularly for patients undergoing cardiac surgery. Implementation and evaluation of an alarm system is important for the battle against postoperative AKI.

Minimal change disease associated with thyroid cancer: a case report.

A patient complaining of edema of the face and lower extremities was admitted to the nephrology department for nephrotic syndrome. Renal biopsy revealed findings of minimal change disease (MCD). Thyroid ultrasound showed a hypoechoic 16 × 13 mm nodule in the right lobe, suspicious of malignancy. Later, total thyroidectomy confirmed the diagnosis of papillary thyroid carcinoma (PTC). After surgery, MCD remitted rapidly and completely, strongly suggesting the diagnosis of MCD secondary to PTC. We report here the first adult case of the paraneoplastic finding of MCD secondary to PTC. Additionally, we discuss the possible role of the BRAF gene in the pathophysiology of PTC-associated MCD in this case and highlight the importance of tumor screening.

Estrogen receptor ß attenuates renal fibrosis by suppressing the transcriptional activity of Smad3.

Renal fibrosis (RF) is a common pathway leading to chronic kidney disease (CKD), which lacks effective treatment. While estrogen receptor beta (ERß) is known to be present in the kidney, its role in RF remains unclear. The present study aimed to investigate the role and underlying mechanism of ERß during RF progression in patients and animal models with CKD. We found that ERß was highly expressed in the proximal tubular epithelial cells (PTECs) in healthy kidneys but its expression was largely lost in patients with immunoglobin A nephropathy (IgAN) and in mice with unilateral ureter obstruction (UUO) and subtotal nephrectomy (5/6Nx). ERß deficiency markedly exacerbated, whereas ERß activation by WAY200070 and DPN attenuated RF in both UUO and 5/6Nx mouse models, suggesting a protective role of ERß in RF. In addition, ERß activation inhibited TGF-ß1/Smad3 signaling, while loss of renal ERß was associated with overactivation of the TGF-ß1/Smad3 pathway. Furthermore, deletion or pharmacological inhibition of Smad3 prevented the loss of ERß and RF. Mechanistically, activation of ERß competitively inhibited the association of Smad3 with the Smad-binding element, thereby downregulating the transcription of the fibrosis-related genes without altering Smad3 phosphorylation in vivo and in vitro. In conclusion, ERß exerts a renoprotective role in CKD by blocking the Smad3 signaling pathway. Thus, ERß may represent as a promising therapeutic agent for RF.

Detecting Neonatal AKI by Serum Cystatin C.

SIGNIFICANCE STATEMENT: Serum creatinine is not a sensitive biomarker for neonatal AKI because it is confounded by maternal creatinine level, gestational age, and neonatal muscle mass. In this multicenter cohort study of 52,333 hospitalized Chinese neonates, the authors proposed serum cystatin C-related criteria (CyNA) for neonatal AKI. They found that cystatin C (Cys-C) is a robust and sensitive biomarker for identifying AKI in neonates who are at an elevated risk of in-hospital mortality and that CyNA detects 6.5 times as many cases as the modified Kidney Disease Improving Global Outcomes creatinine criteria. They also show that AKI can be detected using a single test of Cys-C. These findings suggest that CyNA shows promise as a powerful and easily applicable tool for detecting AKI in neonates. BACKGROUND: Serum creatinine is not a sensitive biomarker for AKI in neonates. A better biomarker-based criterion for neonatal AKI is needed. METHODS: In this large multicenter cohort study, we estimated the upper normal limit (UNL) and reference change value (RCV) of serum cystatin C (Cys-C) in neonates and proposed cystatin C-based criteria (CyNA) for detecting neonatal AKI using these values as the cutoffs. We assessed the association of CyNA-detected AKI with the risk of in-hospital death and compared CyNA performance versus performance of modified Kidney Disease Improving Global Outcomes (KDIGO) creatinine criteria. RESULTS: In this study of 52,333 hospitalized neonates in China, Cys-C level did not vary with gestational age and birth weight and remained relatively stable during the neonatal period. CyNA criteria define AKI by a serum Cys-C of ≥2.2 mg/L (UNL) or an increase in Cys-C of ≥25% (RCV) during the neonatal period. Among 45,839 neonates with measurements of both Cys-C and creatinine, 4513 (9.8%) had AKI detected by CyNA only, 373 (0.8%) by KDIGO only, and 381 (0.8%) by both criteria. Compared with neonates without AKI by both criteria, neonates with AKI detected by CyNA alone had an increased risk of in-hospital mortality (hazard ratio [HR], 2.86; 95% confidence interval [95% CI], 2.02 to 4.04). Neonates with AKI detected by both criteria had an even higher risk of in-hospital mortality (HR, 4.86; 95% CI, 2.84 to 8.29). CONCLUSIONS: Serum Cys-C is a robust and sensitive biomarker for detecting neonatal AKI. Compared with modified KDIGO creatinine criteria, CyNA is 6.5 times more sensitive in identifying neonates at elevated risk of in-hospital mortality.

Use of Histologic Parameters to Predict Glomerular Disease Progression: Findings From the China Kidney Biopsy Cohort Study.

RATIONALE & OBJECTIVE: Challenges in achieving valid risk prediction and stratification impede treatment decisions and clinical research design for patients with glomerular diseases. This study evaluated whether chronic histologic changes, when complementing other clinical data, improved the prediction of disease outcomes across a diverse group of glomerular diseases. STUDY DESIGN: Multicenter retrospective cohort study. SETTING & PARTICIPANTS: 4,982 patients with biopsy-proven glomerular disease who underwent native biopsy at 8 tertiary care hospitals across China in 2004-2020. NEW PREDICTORS & ESTABLISHED PREDICTORS: Chronicity scores depicted as 4 categories of histological chronic change, as well as baseline clinical and demographic variables. OUTCOME: Progression of glomerular disease defined as a composite of kidney failure or a ≥40% decrease in estimated glomerular filtration rate from the measurement at the time of biopsy. ANALYTICAL APPROACH: Multivariable Cox proportional hazard models. The performance of predictive models was evaluated by C statistic, time-dependent area under the receiver operating characteristic curve (AUROC), net reclassification index, integrated discrimination index, and calibration plots. RESULTS: The derivation and validation cohorts included 3,488 and 1,494 patients, respectively. During a median of 31 months of follow-up, a total of 444 (8.9%) patients had disease progression in the 2 cohorts. For prediction of the 2-year risk of disease progression, the AUROC of the model combining chronicity score and the Kidney Failure Risk Equation (KFRE) in the validation cohort was 0.76 (95% CI, 0.65-0.87); in comparison with the KFRE model (AUROC, 0.68 [95% CI, 0.56-0.79]), the combined model was significantly better (P = 0.04). The combined model also had a better fit, with a lower Akaike information criterion and a significant improvement in reclassification as assessed by the integrated discrimination improvements and net reclassification improvements. Similar improvements in predictive performance were observed in subgroup and sensitivity analyses. LIMITATIONS: Selection bias, relatively short follow-up, lack of external validation. CONCLUSIONS: Adding histologic chronicity scores to the KFRE model improved the prediction of kidney disease progression at the time of kidney biopsy in patients with glomerular diseases. PLAIN-LANGUAGE SUMMARY: Risk prediction and stratification remain big challenges for treatment decisions and clinical research design for patients with glomerular diseases. The extent of chronic changes is an important component of kidney biopsy evaluations in glomerular disease. In this large multicenter cohort including 4,982 Chinese adults undergoing native kidney biopsy, we evaluated whether histologic chronicity scores, when added to clinical data, could improve the prediction of disease prognosis for a diverse set of glomerular diseases. We observed that adding histologic chronicity scores to the kidney failure risk equation improved the prediction of kidney disease progression at the time of kidney biopsy in patients with glomerular diseases.

Immunoglobulin heavy chain gene rearrangement in heavy chain deposition disease suggests it is a plasma cell disease: a case report.

Heavy chain deposition disease (HCDD) is characterized by the deposition of truncated monoclonal immunoglobulin heavy chains along glomerular basement membranes. Truncated heavy chains are thought to be associated with plasma cell disease (PCD), but previous bone marrow cytology tests showed that only 30% of HCDD cases are related to PCDs. We report the first known use of immunoglobulin heavy chain (IGH) gene rearrangement to diagnose a patient with γ3-HCDD, although bone marrow morphology test identified no abnormalities. Our findings provide strong evidence for a correlation between PCDs and HCDD, which could help understand the genetic background underlying abnormal heavy chains and assess disease prognosis. Further, concordant with previous findings, bortezomib-based chemotherapy had a good therapeutic effect in our patient. We summarize the experience of diagnosing and treating a case of HCDD, and combine this with a literature review to further explore the correlation between PCDs and HCDD, which has important clinical value.

A mixed-method evaluation of the relationship between Oxford classification scores and longitudinal changes in proteinuria in patients with immunoglobulin A nephropathy.

Introduction: This study aimed to investigate the relationship between Oxford Classification scores and longitudinal changes in proteinuria in patients with immunoglobulin A nephropathy (IgAN). Methods: The study was a single-center retrospective cohort study involving 358 patients with primary IgAN who were treated at the Shenzhen Second People's Hospital, China, between January 2011 and May 2021. Multivariate linear regression and generalized additive mixed models (GAMMs), adjusted for traditional risk confounders, were used to evaluate the correlation between scores for mesangial hypercellularity (M), endocapillary hypercellularity (E), segmental glomerulosclerosis (S), tubular atrophy/interstitial fibrosis (T), and crescents (C) (known as the Oxford Classification MEST-C score system), with proteinuria/creatinine ratio (PCR) at the time of renal biopsy and longitudinal changes in PCR, respectively. Results: The median PCR was 1061 mg/g, and it increased on average by 68.82 mg/g per year in these patients. Among patients with renal insufficiency, compared with patients without relative lesions, those with E present (E1) (1153.44; 95% confidence interval [CI], 188.99-2117.89 mg/g) and C > 0 (C1/2) (1063.58; 95% CI, 185.25-1941.90 mg/g) were associated with increased PCR levels at the time of renal biopsy. What's more, S present (S1) (194.96; 95% CI, 54.50-335.43 mg/g per year) was associated with the fastest PCR increase; C > 0 (C1/2) (147.59; 95% CI, 8.32-286.86 mg/g per year) and T >25% (T1/2) (77.04; 95% CI, 7.18-146.89 mg/g per year), were also correlated with a faster PCR increase. In patients with normal kidney function, associations between S1 (55.46; 95% CI, 8.93-101.99 mg/g per year) and E1 (94.02; 95% CI, 21.47-166.58 mg/g per year) and PCR change could be observed. Additionally, in patients with overweight/obesity, S1 (156.09; 95% CI, 52.41-259.77 mg/g per year), E1 (143.34; 95% CI, 35.30-251.38 mg/g per year), T1/2 (116.04; 95% CI, 22.58-209.51 mg/g per year), as well as C1/2 (134.03; 95% CI, 41.73-226.32 mg/g per year) were associated with noticeably quicker PCR increase. Conclusions: Overall, E1 and C1/2 were independently associated with raised proteinuria levels at the time of renal biopsy, and S1, E1, T1/2, C1/2 were independently associated with a longitudinal increase in proteinuria in the patients with IgAN, especially in those with renal insufficiency or overweight/obesity, suggesting that currently available treatments might not be satisfactory, and weight control might be beneficial. Individual therapy development might benefit from the use of the Oxford Classification system.

The Association of the Oxford Classification Score with Longitudinal Estimated Glomerular Filtration Rate Decline in Patients with Immunoglobulin A Nephropathy: A Mixed-Method Study.

INTRODUCTION: The Oxford Classification score, which predicts renal outcomes for immunoglobulin A nephropathy (IgAN), is widely used in clinical practice. Nevertheless, the relationship between these markers and longitudinal changes in renal function are poorly understood. METHODS: This was a population-based retrospective cohort study of 280 adults with biopsy-proven primary IgAN from 2011 to 2018. We used generalized additive mixed models to control for traditional kidney disease risk factors to analyze the associations between Oxford Classification MEST-C scores (mesangial hypercellularity, M; endocapillary hypercellularity, E; segmental glomerulosclerosis, S; tubular atrophy/interstitial fibrosis, T; crescents, C) and longitudinal changes in the estimated glomerular filtration rate (eGFR) after renal biopsy. RESULTS: The median eGFR was 78.2 mL/min/1.73 m2 at baseline, and then it decreased on average by 1.3 mL/min/1.73 m2 per year in the entire cohort. In adjusted models, compared with patients without relative lesions, the presence of T > 50% (T2) (-5.7; 95% confidence interval [CI], -9.5 to -2.0 mL/min/1.73m2 per year) was associated with the fastest eGFR decline. S present (S1) (-2.9; 95% CI, -4.6 to -1.1 mL/min/1.73m2 per year) and C > 25% glomeruli (C2) (-3.4; 95% CI, -6.4 to -0.5 mL/min/1.73m2 per year) also demonstrated steeper eGFR declines. However, we found no association between M > 0.5 (M1), E present (E1), T 26%-50% (T1), and C present ≥ 1 glomerulus (C1), and progressive eGFR decline (p > 0.05). CONCLUSION: The Oxford Classification scores, S1, T2, and C2, were independently associated with the longitudinal decreases in renal function in patients with IgAN. These findings suggested therapies targeted at improving early damage to these lesions might be essential to delay renal progression.

Kidney Biopsy in Patients With Monoclonal Gammopathy: A Multicenter Retrospective Cohort Study.

Objectives: To analyze the clinical characteristics and renal pathological manifestations of patients with monoclonal gammopathy (MG) and kidney injury. Methods: This was a multicenter retrospective cohort study conducted at four tertiary hospitals in China. The study population comprised patients with MG admitted from January 1 2013 to December 31 2020. Hospitalization records, laboratory data, and kidney biopsy reports of all patients were collected from the electronic hospital information systems. The study outcomes included kidney disease progression and major hemorrhagic complications after kidney biopsy. Results: We identified 1,164 patients with MG, 782 (67.2%) of whom had underlying kidney injury. Of 101 patients who underwent kidney biopsy, 16 had malignant neoplasms. Amyloid nephropathy was the most common finding (n = 34, 33.7%), followed by membranous nephropathy (n = 18, 17.8%) and membranoproliferative nephritis (n = 8, 7.9%). Among 85 patients with non-malignant hematologic conditions who underwent kidney biopsy, 43 had MG of renal significance (MGRS) related lesions and 42 had MG-unrelated lesions. The risk of kidney disease progression was higher in patients with kidney injury than in patients without kidney injury. Conclusion: Among patients with MG and kidney injury, only 12.9% underwent kidney biopsy and more than 40% of these patients had MG-unrelated lesions. A kidney biopsy is safe and essential to maximize the possibility of correct diagnosis for patients with clinically suspected MG of renal significance (MGRS).

Association Between Serum IgG Concentrations and Prognosis in IgA Nephropathy.

INTRODUCTION: To investigate the relationship between serum IgG (sIgG) concentration and the prognosis of IgA nephropathy (IgAN). METHODS: A total of 309 patients with biopsy-proven IgAN in the Second Referral Hospital of Shenzhen were enrolled between 2010/01 and 2017/06. Patients were divided into 3 groups on the basis of sIgG tertiles: < 8.99 g/L (Group G1), 8.99 to 11.17 g/L (Group G2), and > 11.17 g/L (Group G3). RESULTS: As the level of sIgG increased, there was a decrease in DBP, serum creatinine, 24h urine proteinuria and an increase in serum albumin (all P < .05). In terms of pathological manifestations, with increasing sIgG levels, there was a tendency of decline in the Lee's grading system or high-grade tubular atrophy/interstitial fibrosis or in the proportion of glomerular sclerosis and the ratio of crescent (all P < .05). Kaplan-Meier analysis indicated that the cumulative renal survivals rates were significantly higher in patients with elevated sIgG (P < .05). Cox regression analysis showed that after adjusting for gender, age, BMI, and clinical indicators (BP, 24h urine proteinuria, eGFR, M, E, S, T, and the ratio of crescent), decreased sIgG level at the time of renal biopsy is an independent risk factor for unfavorable outcomes in IgAN. Furthmore, every 1 g/L decrease in sIgG level was associated with a 1.74-fold (95% CI: 1.30 to 5.38) increased risk of the incidence of composite renal outcomes. CONCLUSIONS: Decreased serum IgG level at baseline might be a kind of predictive marker for the poor prognosis of IgAN.

Circulating MiR-29a, Possible Use as a Biomarker for Monitoring IgA Nephropathy.

INTRODUCTION: Previous studies have shown that TGF-ß1/Smad3 signaling promotes renal fibrosis by inhibiting miR-29. To date, only few studies have reportedon circulating microRNAs in IgA nephropathy (IgAN). However, the plasma expression of miR-29a and its role in patients with IgAN remains unclear. In this study, we attempted to elucidate whether plasma miR-29a expression can be used as a biomarker for monitoring disease states. METHODS: For this study, 15 healthy subjects, 36 patients with untreated renal biopsy-proven IgAN, and 79 patients with IgAN, who were under treatment for a period of 1 year on an average, all of whom had similar age and gender distributions, were included. The plasma expression of miR-29a in each group was explored by real-time PCR, and the relationship between miR-29a expression and clinical, pathological, and prognostic indicators of IgAN was further evaluated. RESULTS: Relative plasma expression of miR-29a in patients with IgAN was significantly lower than that in healthy controls (P < .001), and these changes in plasma miR-29a could be suppressed by treatment (P < .05). Plasma miR-29a was positively correlated with eGFR and negatively correlated with proteinuria and serum creatinine, irrespective of whether or not the patients with IgAN accepted treatment (P < .05). Plasma miR-29a level was negatively correlated with primary pathological parameters such as crescent formation, Lee's and Oxford classification (P < .05). Kaplan-Meier analysis revealed that patients with high plasma expression of miR-29a had better renal function and better response to treatment compared to those with low expression (P < .05). CONCLUSION: Plasma miR-29a could be considered as a biological marker that reflects renal damage and function, to predict the progression of IgAN.

Comparison of three nutritional screening tools for predicting mortality in maintenance hemodialysis patients.

OBJECTIVES: The aim of this study was to compare the effect of different nutritional screening tools on predicting the risk for mortality in patients on maintenance hemodialysis (MHD). METHODS: A cohort of 1025 patients on MHD were enrolled from eight hospitals. The malnutrition-inflammation score (MIS), objective score of nutrition on dialysis (OSND), and geriatric nutritional risk index (GNRI) were measured at baseline. All-cause mortality and cardiovascular (CV) mortality were the major study outcomes. RESULTS: The median follow-up duration was 28.1 mo. The MIS (per SD increase, hazard ratio [HR], 1.35; 95% confidence interval [CI], 1.18-1.55), the OSND (per SD decrease, HR, 1.24; 95% CI, 1.09-1.42), and the GNRI (per SD decrease, HR, 1.26; 95% CI, 1.10-1.43) were significantly associated with the risk for all-cause mortality. More importantly, the mortality predictability of the MIS appears similar to the GNRI (P = 0.182) and greater than the OSND (MIS versus OSND: P = 0.001; GNRI versus OSND: P = 0.045). Similar results were found for CV mortality. CONCLUSIONS: Each of the three nutritional screening tools was significantly associated with an increased risk for all-cause and CV mortality. The mortality predictability of the MIS was similar to the GNRI and greater than the OSND.

Interleukin-23A is associated with tumor growth in Helicobacter-pylori-related human gastric cancer.

BACKGROUND: Interleukin (IL)-23 is one of the newly identified inflammatory cytokines, and inflammation is also known to be related to the development of gastric cancer (GC). The role of IL-23 in gastric cancer, however, is largely unknown. In the present study, we investigated the expression and possible role of IL-23A in human GC. METHODS: The expression of IL-23A and IL-17A in human GC tissues was determined by immunohistochemistry, and the relationship between IL-23A expression and clinical characteristics of GC was investigated. The serum concentration of IL-23A and IL-17A was also tested by ELISA. The source and role of IL-23A in GC were studied in vitro by Flowcytometry, MTS (Owen's reagent) assay and Western blot. RESULTS: IL-23A, IL-23 receptor (IL-23R) and IL-17A were all overexpressed in human GC tissues, and the level of IL-23A was well correlated with IL-17A in GC tissues as well as in patient's serum. Macrophages and GC cells were the main source of IL-23A secretion upon stimulation of H. pylori lysate. Furthermore, we found that IL-23A promoted proliferation of GC cell lines via IL-17A/IL-17 receptor antagonist (IL-17RA) /nuclear factor-κB (NF-κB) signaling. CONCLUSIONS: The high expression of IL-23A is associated with GC. IL-23A can promoted GC cells growth by inducing the secretion of IL-17A in tumor microenvironment. Our results suggest that the serum concentration of IL-23A is a good biomarker of poor clinical prognosis in GC patients.

Prevalence and related factors of the absence of anemia among Chinese chronic hemodialysis patients: a multicenter cross-sectional study.

BACKGROUND: Some chronic hemodialysis (HD) patients can maintain normal hemoglobin levels without requiring erythropoiesis-stimulating agents (ESAs). However, the prevalence and the factors associated with this condition in Chinese chronic HD patients have not been reported. The aim of this study was to investigate clinical features, iron metabolism, and other characteristics to survey the prevalence rate and the related factors of this condition among Chinese chronic HD patients. METHODS: A total of 1,318 chronic HD patients participated in this study. The patients were classified into a non-ESA group (n = 11) and an ESA group (n = 1,307). The r-HuEPO-independent (non-ESA) HD patients were defined as having hemoglobin greater than 12 g/dl for more than 6 months without r-HuEPO injection, blood transfusion, or androgen therapy. Epidemiological and laboratory data were collected. Renal sonography was also performed on each patient to evaluate the formation of renal and liver cysts, and the number and size of the cysts were recorded. RESULTS: Approximately 0.84 % of all HD patients were found to be r-HuEPO independent. The non-ESA group had a higher proportion of men (79.6 vs. 58.3 %), a longer duration of renal replacement therapy (RRT) (8.6 ± 6.1 vs. 5.1 ± 3.3 years), a higher prevalence of adult polycystic kidney disease (APKD) (46.3 vs. 9.7 %), a higher prevalence of hepatitis C virus (HCV) liver disease (26.2 vs. 3.2 %, P < 0.01), and had older patients (63.3 ± 13.6 vs. 49.6 ± 13.5 years). Endogenous erythropoietin levels in the non-ESA group were significantly higher than those in the ESA group (61.8 ± 27.1 vs. 29.3 ± 11.7 mU/ml). Non-ESA patients had a significantly higher number of renal (38.1 vs. 13.2 %) and hepatic cysts (9.3 vs. 1.9 %), which were also larger in size (2.9 ± 1.6 vs. 1.3 ± 0.3 cm) compared with those of patients in the ESA group. No significant difference in iron metabolism was found between two groups. In the multivariate Cox analysis, the independent predictor factors for the absence of anemia in these HD patients were the number of renal cysts >6 cysts (95 % CI 1.058-1.405; P = 0.00), endogenous erythropoietin levels (95 % CI 1.139-1.361; P = 0.05), HCV+ liver disease (95 % CI 1.129-1.316; P = 0.01), and time on RRT (95 % CI 1.019-1.263; P = 0.05). CONCLUSIONS: To our knowledge, this study is the first to report on r-HuEPO independence among Chinese HD patients. The prevalence among Chinese chronic HD patients is significantly lower than that reported in the literature. Factors contributing to this condition are complex and multiple. The frequency of this condition is higher in men and in older patients with long-term RRT, in patients with HCV+ liver disease, and in APKD patients. This condition is associated with increased endogenous erythropoietin production and the presence of renal and hepatic cysts.