Current clinical profiles for Chinese hemodialysis patients

Abstract

The prevalence of hemodialysis (HD) patients in China is escalating, necessitating a comprehensive understanding of their clinical profiles. This study offers an in-depth analysis of the baseline data from the China Dialysis Outcomes and Practice Patterns Study (DOPPS) Phase 7 (DOPPS7), aiming to assess the current clinical characteristics and target ranges for the most recent years. It also compares these findings with those from DOPPS Phase 5. The DOPPS is a well-regarded international, prospective, and observational cohort study. Our analysis focused on the initial sample of patients enrolled in China DOPPS7. We report the demographic and clinical characteristics of 1843 patients, with a mean age of 61 ± 14 years and a male predominance (60.7%). The median dialysis vintage was 2.64 years, with diabetes (31.7%) and chronic glomerulonephritis (21.4%) being the leading causes of end-stage kidney disease (ESKD). Notably, 81.2% of patients had a single-pooled Kt/V ≥ 1.2, and 80.5% maintained albumin levels > 3.5 g/dl. Hemoglobin levels within the target range (110–130 g/dl) were observed in 44.2% of patients, while serum calcium (8.4–10.2 mg/dl) and phosphate (3.5–5.5 mg/dl) were within target ranges in 63.8% and 38.3% of patients, respectively. PTH levels were maintained within 150–600 pg/dl in 57.6% of patients, and 84.7% utilized fistula as their vascular access. Significant variations were noted in demographic, clinical, laboratory, and treatment characteristics among the three cities involved in the study. Compared to DOPPS5, improvements were observed in the proportion of patients meeting standards for hemoglobin, blood phosphorus, iPTH, and spKTV, while serum calcium, TSAT, and ferritin levels remained relatively stable. However, an increase in the proportion of patients with albumin < 3.5 g/dl was noted. The study’s limitations include the exclusion of patients from smaller cities and remote areas, where HD patient conditions might differ significantly from those reported.

Introduction

Hemodialysis (HD) patient numbers in China are escalating annually, with a reported increase from 578,000 in 2016 to 844,000 in 2023¹. As a populous Asian nation, China presents significant demographic, economic, and healthcare system differences compared to developed Western countries, including variations in dialysis frequency, medication availability, and medical practice patterns. Despite these factors, comprehensive data on the clinical characteristics and medical practices of HD patients in China remains limited. China’s vast geography and economic disparities contribute to regional variations in patient characteristics and dialysis practices, which have been difficult to capture due to inconsistent research methodologies in previous studies.

The Dialysis Outcomes and Practice Patterns Study (DOPPS) is an internationally recognized prospective cohort study that provides a valuable framework for understanding HD patient profiles². We have reported HD patients’ profile in DOPPS 5 (2012–2015)³. However, in the past decade, drugs and technology have undergone significant changes. Understanding the current characteristics of HD patients in China is of great significance for understanding the challenges faced by all stakeholders and even policy makers. This study aims to fill the gap in knowledge by presenting the baseline data from China DOPPS 7, offering a comparative analysis among different cities and historical data from DOPPS 5 to figure out the changes. The findings are crucial for tailoring optimal treatment managements for Chinese HD patients and fostering the exchange of real-world data across different regions.

This article specifically aims to elucidate the current treatment status of HD patients in China, compare the clinical characteristics and practices across 3 main cities in China, and assess changes in patient managements over the past decade. The insights gained from this study are expected to enhance dialysis practices and improve patient prognoses, contributing to a broader understanding of HD patient management globally.

Method

Study design and subjects

The Dialysis Outcomes and Practice Patterns Study (DOPPS), initiated in 1996, is an international, multicenter, prospective cohort study that includes hemodialysis (HD) patients^2,4. Inclusion criteria were set at age 18 years or older, treatment at an in-center dialysis clinic, and receiving chronic, maintenance HD for more than three months. Patients under 18, those on home-based dialysis, or those receiving HD for acute kidney injury were excluded. China joined DOPPS study in 2011. For China DOPPS study, Beijing, Shanghai, and Guangzhou—the largest cities in the northern, central, and southern regions respectively—were selected to ensure representation across different economic and healthcare landscapes^5,6. We randomly selected an average of 30 patients from altogether 45 dialysis facilities. This has been described in previous publications⁴. To maintain a consistent sample size, departing patients were annually replaced by new patients who had joined the facility since the last sampling. The inclusion criteria were as follows: (1) receiving chronic in-center HD; (2) patients’ age ≥ 18 years-old; (3) expectation that patient will continue to receive care at the dialysis clinic. The exclusion criteria were: (1) treated with a home-based dialysis modality; (2) Receiving HD for acute kidney injury; (3) expectation that patient will receive dialysis transiently (< 6 weeks) at the study site (e.g., anticipated transfer to another dialysis facility). (4) Receiving concomitant peritoneal dialysis and hemodialysis (hybrid therapy utilized in Japan only). Demographic information, comorbid conditions, laboratory values, and dialysis prescriptions are extracted from medical records using consistent and standardized data collection tools known as DOPPS-link. For the current analysis, we utilized data from patients who participated in DOPPS phase 7, which spanned from 2018 to 2022.

All data generated or analyzed during this study are included in this article. Further enquiries can be directed to the DOPPS project; ; see https://www.dopps.org/PartnerwithUs.aspx for more information. The study was approved by the Ethics Committee of Peking University People’s Hospital (ethical approval number: 2018PHB028-01). Other participating sub-centers also obtained ethics committee approval documents prior to the start of clinical trials. All patients provided written, informed consent. The authors confirm that all the methods used in this study comply with the ethical standards of the relevant national and institutional committees on human experimentation and with the Helsinki Declaration.

Data collection

Data for all census patients were collected, including both simple and detailed data for the sample patients. Data collection primarily utilized questionnaires; each patient completed the medical questionnaire (MQ) at enrollment as baseline data, which included dialysis protocol, laboratory values prior to maintenance dialysis, vascular access usage and comorbidities. Interval summary (IS) was compiled every four months and encompassed laboratory values, dialysis prescriptions, residual renal function assessments, and overall dialysis treatment situations. The aforementioned questionnaires were administered by the study coordinator.

This study primarily presents the baseline data of patients who participated in the research, and it compares the demographic and clinical characteristics among patients from Beijing, Guangzhou, and Shanghai. The reported data encompasses age, sex, etiology of end-stage renal disease (ESRD), dialysis vintage, body mass index (BMI), comorbidities, vascular access type, single-pool Kt/V (spKt/V), hemoglobin (HGB), ferritin levels, transferrin saturation (TSAT), serum albumin (ALB), corrected calcium (cCa), phosphorus (P), and intact parathyroid hormone (iPTH). Vintage was defined as the duration of dialysis up to the time of enrollment. Vascular access was defined as the dialysis pathway used when patients were enrolled in the study. Laboratory values primarily originated from MQ and spKt/V utilizes the data compiled in the latest IS.

Statistics

Generally, we adopted the same statistical analysis method as used for DOPPS5. Continuous variables were expressed as mean ± standard deviation or median with interquartile range, while categorical data were presented as percentages. To ensure the results were representative of the overall HD patient population, given the variability in facility size, the data were weighted by the facility sampling fraction. Differences in mean or median between groups were evaluated by using analysis of variance or nonparametric tests. And categorical data were compared by using the chi-square test. Given the descriptive nature of this article, missing data were not statistically imputed. All statistical analyses were conducted using SPSS version 22 and Microsoft Excel 2019.

Result

Initially, the study enrolled 1843 patients. One participant, lacking gender information, was excluded from the analysis. The average age of the participants was 61 years, with a standard deviation of 14 years. Males constituted 60.7% of the study population. The primary cause of end-stage kidney disease (ESKD) was diabetic nephropathy (DN), accounting for 31.4% of cases, followed by chronic glomerulonephritis (CGN) at 21.4%, and hypertensive nephropathy at 11.7%. The median dialysis vintage was 2.64 years, with 29.4% undergoing dialysis for over 5 years. Notably, Shanghai had the longest median dialysis vintage at 3.74 years (IQR: 0.48, 9.38), exceeding Beijing at 3.39 years (IQR: 0.96, 7.24), and Guangzhou at 1.81 years (IQR: 0.49, 4.89). The mean BMI was highest in Beijing, and the smoking rate was also most prevalent there, at 37.9%. The study revealed the following prevalence rates for cardiovascular comorbidities: coronary heart disease affected 30.4% of patients, congestive heart failure was present in 27.4%, and other cardiovascular diseases were found in 18.0%. Notably, there were variations in the prevalence of these comorbidities across the three cities studied. Beijing exhibited a higher rate of combined cardiovascular and cerebrovascular disease (refer to Table 1 for detailed comparisons).

Table 1. Demographics and patient characteristics of the cohort study by region. BMI body mass index, CGNchronic glomerulonephritis, DN diabetic nephropathy, HT hypertensive nephropathy, spkt/v single-pooled kt/v, stdkt/v standardized kt/v, HDF hemodiafiltration, Hgb hemoglobin, ALB albumin, TSAT transferrin saturation, cCa corrected calcium, P phosphate, iPTH intact parathyroid hormone, PCS physical component summary, MCS mental component summary.

Variables	All	Region Beijing	Guangzhou	Shanghai	P
Sample patients	1843	605	678	560
Facilities	42	14	15	13
Demographics
Age	60.8 ± 13.8	60.8 ± 13.8	60.7 ± 14.4	60.9 ± 13.1	0.937
Male(%)	60.7	60.8	61.1	60.7	0.922
Diabetes(%)	35.3	41.0	36.5	27.1	< 0.001
Dialysis vintage(years)	2.6(0.7,7.0)	3.4(1.0, 7.2)	1.8(0.5,4.9)	3.7(0.5,9.4)	< 0.001
BMI(kg/m2)	22.6 ± 3.8	23.6 ± 4.0	21.9 ± 3.5	22.2 ± 3.5	< 0.001
Assigned primary ESKD causes
DN(%)	31.7	38.2	31.1	24.4
HT(%)	11.7	13.2	10.7	11.2
CGN(%)	21.4	14.3	19.3	32.4
Others(%)	35.2	34.4	39.0	31.9
Dialysis prescription
spKt/V	1.35(1.25,1.46)	1. 35(1.23,1.50)	1.36(1.28,1.45)	1.33(1.22,1.44)	0.025
spKt/V > 1.2(%)	81.2	78.8	87.2	78.3
Vascular access type
Fistula	1373(85.5%)	481(84.5%)	450(82.6%)	442(89.8)
Catheter	233(14.5%)	88(15.5%)	95(17.4%)	50(10.2%)
Dialysis frequency
1 times per weak	11(0.6%)	0(0)	6(0.9%)	5(0.9%)
2 times per weak	113(6.1%)	24(4.0%)	53(7.8%)	36(6.4%)
3 times per weak	1695(92%)	562(92.9%)	616(90.9%)	517(92.3%)
3 /4 times	10(0.5%)	7(1.2%)	2(0.3%)	1(0.2%)
4 times per weak	14(0.8%)	12(2.0%)	1(0.1%)	1(0.2%)
Blood flow rate (ml/min)	230(220,250)	250(230,260)	230(200,230)	230(220,250)	< 0.0001
Intradialytic weight loss(Kg)	2.3(1.7, 2.9)	2.5(1.7,3.2)	2.2(1.6,2.9)	2.4(1.7,2.9)	< 0.0001
Laboratory values
Alb(g/dl)	3.8 ± 0.4	3.9 ± 0.4	3.8 ± 0.4	3.9 ± 0.38	< 0.001
Hgb(g/dl)	10.9(9.9,11.9)	11.1(10.3,11.8)	10.7(9.6,11.8)	11.0(10.0,11.9)	< 0.0001
Ferritin(ng/ml)	220.0(88.4,383.4)	248.7(103.3,394.0)	238.3(111.0,407.1)	156.6(63.0,356.0)	< 0.001
TSAT(%)	25.2(19.5,31.2)	24.6(18.6,30.1)	25.8(20.0,31.3)	26.2(20.0,33.0)	0.004
cCa(mg/dl)	9.0(8.4,9.6)	9.0(8.5,9.5)	8.87(8.3,9.4)	9.2(8.6,10.0)	< 0.0001
P(mg/dl)	5.5(4.4,6.8)	5.3(4.3,6.4)	5.92(4.6,7.2)	5.5(4.5,6.7)	< 0.001
iPTH(pg/dl)	251.9 (139.6, 462.7)	241.2 (132.2, 386.8)	263.8(144.4,509.4)	260.4(141.6,490.8)	0.142
Comorbidities
Coronary heart disease(%)	30.4	34.4	21.1	36.1	< 0.001
Cancer(%)	4.5	6.4	3.0	4.0	0.003
Other cardiovascular disease(%)	18.0	19.1	15.3	19.7	0.144
Cerebrovascular disease(%)	15.4	18.4	16.7	15.4	0.001
Congestive heart failure(%)	27.4	27.4	30.4	24.2	0.004
Diabetes(%)	39.1	44.6	38.6	39.1	< 0.001
Fracture(%)	1.4	1.9	1.4	0.8	0.152
GI bleeding(%)	2.0	1.7	2.0	2.2	0.823
Hepatitis(%)	7.1	2.0	10.5	9.4	< 0.001
Hpertension(%)(%)	87.8	90.8	84.0	88.6	0.001
Lung disease(%)	4.9	4.0	5.2	5.7	0.062
Neurologic disease(%)	5.5	5.1	5.9	5.6	0.546
Peripheral Vascular Disease(%)	12.8	14.4	14.8	8.8	0.001
Recurrent Cellulitis, Gangrene(%)	1.8	2.9	1.7	0.6	0.005

Assigned primary ESKD causes

Diabetic nephropathy (DN) was the predominant cause of ESKD, accounting for 31.7% of cases, followed by CGN at 21.4%, and hypertensive nephropathy at 11.7%, with others at 35.2%. There was significant variation in the distribution of primary ESKD causes among cities. Shanghai had a notably higher proportion of CGN at 32.4% compared to Beijing and Guangzhou (14.3% and 19.3%, respectively). Conversely, the proportion of DN in Beijing (38.2%) was significantly higher than in the other cities (Fig. 1A). Among patients under 45, CGN was more common as a primary cause (37.3%), while in older patients, DN and hypertensive nephropathy were more prevalent (Fig. 1B). Compared to the DOPPS5 study, the proportion of DN has increased, becoming the main cause of ESKD.

Fig. 1 [Images not available. See PDF.]

The distribution of the assigned primary ESKD causes, dialysis vintage and spKt/V. (A) The distribution of the assigned primary ESKD causes stratified by city group; (B) the distribution of the assigned primary ESKD causes stratified by age group; (C) the distribution of dialysis vintage stratified by city and gender groups; (D) the distribution of spKt/V stratified by city and gender groups; (E) the distribution of spKt/V stratified by age groups.

Dialysis vintage

There was 35.9% of patients with less than one year of dialysis vintage, 34.8% within the one to five-year range of dialysis vintage, and 29.4% a dialysis vintage exceeding five years. Patients have shorter dialysis vintages, with a lower proportion in the 5–10 years range (18.3%) in Guangzhou compared to Beijing (31.3%) and Shanghai (39.7%). Additionally, Guangzhou has a higher proportion of patients with less than one year of vintage (44.4%). No difference is found in terms of gender ( Fig. 1C).

SPKTV

At baseline, 18.8% of patients had a single-pool Kt/V (spKt/V) less than 1.2, 42.2% were in the 1.2–1.39 range, 26.7% in the 1.4–1.59 range, and 12.2% were 1.6 or higher. Guangzhou showed a lower prevalence of low spKt/V compared to Beijing and Shanghai. A significant difference was observed between male and female patients, with a higher proportion of males having low spKt/V (24.7% vs. 9.7%) (Fig. 1D). Patients under 55 had a higher proportion of spKt/V levels below 1.2 (Fig. 1E). Compared to DOPPS5, the proportion of patients meeting the spKt/V standard increased from 74.1 to 81.2%.

Albumin

40.1% of patients had serum albumin (ALB) levels above 4.0 g/dl, 40.4% were in the 3.5–3.9 g/dl range, and 19.6% had levels below 3.5 g/dl. Guangzhou had a higher proportion of patients with low ALB levels compared to Beijing and Shanghai. Older patients had lower ALB levels compared to younger patients (Fig. 2A). Compared to DOPPS5, the proportion of patients with low ALB levels increased from 13.4 to 19.5%.

Fig. 2 [Images not available. See PDF.]

The distribution of ALB (g/dl), Hgb (g/dl), ferritin (ng/ml) and TSAT (%). (A) The distribution of serum ALB level stratified by city and age group; (B) the distribution of serum Hgb level stratified by city and age group; (C) the distribution of serum ferritin level stratified by city and age group; (D) the distribution of TSAT stratified by city and age group.

Anemia

13.7% of patients had hemoglobin (Hgb) levels below 9 g/dl, with Guangzhou showing a higher percentage (18.5%) compared to Beijing (9.1%) and Shanghai (13.8%). 44.2% of patients had hemoglobin within the target range of 110–130 g/L. Patients under 45 had a higher proportion of Hb levels below 9 g/dl (Fig. 2B). 33.0% of patients had serum ferritin levels below 200 ng/ml, and 27.1% had levels above 500 ng/ml. Shanghai had a higher proportion of patients with low ferritin levels (59.4%) and a lower proportion with high ferritin levels (11.4%) compared to Beijing and Guangzhou (Fig. 2C). 61.2% of patients had transferrin saturation (TSAT) levels between 20 and 50%, 33.8% had TSAT levels below 20%, and 5.0% had levels above 50%. Guangzhou had a lower proportion of patients with TSAT in the 20–50% range (54.6%) compared to Beijing (64.7%) and Shanghai (65.4%) (Fig. 2D).

Chronic kidney disease-mineral and bone disorder (CKD-MBD) management

63.8% of patients had corrected calcium (cCa) levels within the target range of 8.4–10.2 mg/dl. Guangzhou had a higher proportion of patients with cCa levels below 8.4 mg/dl (37.5%) compared to Beijing and Shanghai (24.7% and 27.4%, respectively) (Fig. 3A). Male patients and patients under 45 had a higher proportion of cCa levels below 8.4 mg/dl. (Fig. 3B).

Fig. 3 [Images not available. See PDF.]

The distribution of bone mineral markers. (A) The distribution of serum cCa (mg/dl) stratified by city and gender groups; (B)The distribution of serum cCa stratified by age groups (C) the distribution of serum P (mg/dl) stratified by city and age groups; (D) the distribution of iPTH (pg/dl) stratified by city and age groups.

In comparison with the DOPPS5 data, the proportion of patients meeting the blood calcium standard remained relatively stable, with a slight decrease from 66.5 to 63.8%. Only 38.3% of patients had serum phosphate (P) levels within the target range of 3.5–5.5 mg/dl. A significant portion, 28.2%, had levels in the 5.6–7.0 mg/dl range, while 23.2% had levels above 7.0 mg/dl. Notably, Beijing had a lower percentage of patients with high serum P levels at 18.0%, in contrast to Shanghai and Guangzhou, as shown in Fig. 3C. Younger patients, particularly those under 45, were more likely to have poorly controlled serum P levels. Regarding intact parathyroid hormone (iPTH) levels, only 57.6% of patients were within the target range of 150–600 pg/dl. Guangzhou had a higher proportion of patients with iPTH levels exceeding 600 pg/dl (20.8%) compared to Beijing and Shanghai, as depicted in Fig. 3D. Older patients, especially those aged 65 and above, exhibited a different distribution of PTH levels. There was an increase in the proportion of patients meeting PTH standards when compared to DOPPS5, rising from 51.2 to 57.6%.

Vascular access

Fistula was the predominant form of vascular access in use, utilized by 84.7% of the patients. Notably, Shanghai reported the highest rate of fistula usage at 89%, surpassing other cities as depicted in Fig. 4A. Interestingly, the adoption of fistulas was less common among older patients when compared to their younger counterparts, as illustrated in Fig. 4B. Additionally, patients with diabetes were found to have a lower rate of fistula use, as shown in Fig. 4C.

Fig. 4 [Images not available. See PDF.]

The distribution of vascular access. (A) the distribution of vascular access type stratified by city; (B) the distribution of vascular access type stratified by gender; (C) the distribution of vascular access type stratified by primary ESKD causes groups.

Dialysis frequency and modality

In DOPPS 7, 92% of the HD patients who were on 3 time per week, while for DOPPS5, China has only 79.8% of patients on dialysis thrice per week. In the current study, 52.8% of patients only undergo hemodialysis (HD), 3.7% of patients only receive hemodialysis filtration (HDF), and 43.5% of patients receive hybrid dialysis modes of HD and HF (HDF). Compared to the 9.8% HDF utilization rate of DOPSS5, the proportion of patients receiving HDF treatment in this study was significantly increased.

Discussion

This study offers a comprehensive analysis of the baseline characteristics of HD patients in China as part of DOPPS7, with emphasis placed on regional disparities. When compared with DOPPS5, recent changes in HD patient profiles were observed. Significant variations were noted in demographic, clinical, laboratory, and treatment characteristics among the three major cities studied. Improvements were seen in the proportion of patients meeting therapeutic targets for hemoglobin, blood phosphorus, iPTH, and spKTV, while serum calcium, TSAT, and ferritin levels remained stable. The findings provide valuable insights into the current state of HD care in China, which has the largest dialysis population and continues to see a growing number of incident patients.

Diabetic nephropathy (DN) emerged as the primary cause of ESKD in China, consistent with global trends³. However, the proportion of DN and CGN as causes of ESRD varied regionally, with a higher prevalence of CGN in younger patients. This could be attributed to differences in environmental factors, healthcare access, and genetic predispositions. To some extent, DN can be prevented and controlled. Early detection and comprehensive management of diabetes can prevent and control the complications of diabetes. Diabetes has been considered as the main chronic disease that China implements comprehensive prevention and management strategy. Since 2009, diabetes prevention and management at the basic level has been promoted and implemented nationwide as a national basic public health service project⁷. However, the prevention and management of diabetes in China still faces great challenges. We need to cooperate closely with endocrinologists to manage diabetes well and conduct early screening of diabetes nephropathy. Take measures to control blood sugar, blood pressure, blood lipids, and use drugs to improve the heart and kidney outcomes for the diabetic patients. So as to delay the progress to ESKD for patients with diabetes nephropathy. This is now considered an important public health strategy in China.

The observation of regional differences in comorbidity rates among cities, such as the higher rate of combined cardiovascular and cerebrovascular disease in Beijing, as noted in this study, is an important finding. Beijing represents the northern part of China, while Shanghai and Guangzhou are located in the southern part of the country. These three cities differ in their geographical location, culture, economy, and medical practices within China, and these differences may impact the health status and disease patterns of their residents. Air pollution, climate, and other environmental conditions can have an impact on health outcomes, particularly for cardiovascular and respiratory diseases⁸. Diet, physical activity levels, smoking, and alcohol consumption can vary by region and contribute to differences in disease prevalence. The availability and quality of healthcare services can differ across regions, affecting the diagnosis, treatment, and management of comorbidities. Socioeconomic status can influence health behaviors and access to healthcare, leading to variations in disease rates. Differences in health policies and insurance coverage can affect the utilization of healthcare services and the quality of care received. The consistency of these regional variations between DOPPS5 and DOPPS7 suggests that these differences are not transient but rather reflect underlying structural and societal factors. The vast geography of China, with its diverse populations and varying levels of economic development, indeed warrants further research to understand these disparities better. We will conduct more localized epidemiological studies to better understand the factors contributing to these health disparities and implement targeted public health interventions that address the specific needs and challenges of each region.

Our nuanced analysis delineates the distribution of patients across varying dialysis vintage categories. Undoubtedly, dialysis vintage—the duration of dialysis treatment—is a pivotal factor influencing mortality rates among hemodialysis patients⁹. As patients undergo prolonged dialysis, their risk of complications that can impact survival escalates⁹. For instance, patients on long-term dialysis frequently contend with cardiovascular diseases, a leading cause of mortality in this patient population. The extended exposure to uremia and the dialysis treatment itself can facilitate the onset and progression of cardiovascular issues¹⁰. Moreover, patients with a longer dialysis vintage may experience a loss of appetite, protein malnutrition, and challenges in maintaining adequate nutrition. Malnutrition can compromise the immune system and heighten the risk of additional complications. In China, the dialysis vintage (median 2.6 years) is relatively shorter when compared to Japan, European countries, and the United States (median 7.9, 5.0, and 3.7 years, respectively)¹¹. Several factors may contribute to this disparity: (1) The emergence of new dialysis patients in China, partly driven by advancements in therapeutic technology, the development of more effective medications, the enhancement of healthcare reimbursement policies, and the expansion of medical accessibility. (2) China’s dialysis technology, despite significant recent progress, still lags behind Japan and other western countries in aspects such as equipment quality, water treatment, and dialysis techniques. (3) While China’s healthcare system continues to improve, regional disparities persist in medical insurance reimbursement policies and benefit levels. (4) In China, certain patients and families may harbor biases or fears regarding dialysis, perceiving it as a treatment of last resort. This perception can result in delayed dialysis initiation or poor adherence to treatment, ultimately shortening dialysis vintage. These factors collectively impact the long-term stability of dialysis treatment and the potential extension of dialysis vintage.

Our findings highlight several key aspects of HD practice and its evolution over time. (1) An overall within the target rate of 81.2% for spKt/V indicates that a majority of patients are receiving adequate dialysis according to the standards, which is an improvement compared to the DOPPS 5 study. spKt/V is a measure of dialysis dose adequacy, and achieving target rates is associated with better patient outcomes. Despite adequate dialysis dose, the study noted that the mean BFR remained low and unchanged. BFR is a critical parameter in HD as it affects the efficiency of solute removal. A low BFR may limit the effectiveness of dialysis sessions, suggesting that there is room for optimization by increasing BFR within a safe range for individual patients. (2) An increase in the number of patients undergoing HD three times a week is likely a result of economic development and improvements in medical insurance policies in China. In DOPPS 5 study, 26% of Chinese patients underwent two-times weekly hemodialysis, compared to 6.7% in DOPPS7 and less than 5% in other DOPPS regions. This increased frequency can lead to better control of uremia and related complications. (3) The study observed a positive trend in the use of HDF, which combines convective and diffusive clearance mechanisms, potentially offering survival advantages over conventional HD modality¹² HDF is known to remove middle molecules more effectively than standard HD. However, unlike practices in some Western countries, where HDF is often performed three times a week, our study found that most patients were on a hybrid dialysis mode, combining HD and HDF. The development of the Chinese economy and improvements in medical insurance policies have likely contributed to the ability of more patients to access frequent dialysis treatments, including HDF, which can be more costly. Our study suggests a need to optimize dialysis prescriptions to ensure that patients receive adequate treatment. This could involve adjusting the dialysis dose, BFR, session length, and frequency based on individual patient needs and response to treatment. The benefits of our hybrid HD mode need further analysis to determine if it provides additional advantages over standard treatment regimens.

Despite some improvements in anemia management, a significant proportion of patients still present with hemoglobin levels outside the recommended range. Currently, the primary therapeutic agents for treating renal anemia can be categorized into three groups: erythropoiesis-stimulating agents (ESAs), iron supplements, and hypoxia-inducible factor prolyl hydroxylase inhibitors (HIF-PHIs). Among these, HIF-PHIs represent a novel class of drugs introduced for the treatment of renal anemia. They were officially approved for clinical use in China at the end of 2018. HIF-PHIs function by inhibiting HIF prolyl hydroxylase enzymes, thereby stabilizing intracellular HIF levels. This stabilization regulates and enhances the production of endogenous erythropoietin (EPO) at physiological concentrations while promoting the expression of its receptors. Furthermore, HIF-PHIs facilitate the expression of proteins involved in iron metabolism, thus comprehensively regulating processes within the body to stimulate red blood cell production. The introduction of HIF-PHIs offers new treatment options and helps to improve the management^13,14, but their optimal use requires further research and refinement¹⁵.

Our study reveals that there are still unmet needs in the treatment of CKD - MBD. Although updated guidelines and treatment protocols are in place, several challenges and gaps in the management of CKD - MBD need to be resolved to enhance patient outcomes. Firstly, increasing the frequency of testing is crucial for enabling precise diagnoses and timely treatment plan adjustments. Adherence to KDIGO guidelines is vital in this regard¹⁶. However, in comparison with Japan and many Western countries, patients in China undergo less frequent testing¹⁷. Secondly, the improved control of P and iPTH in the DOPPS 7 study might stem from the availability of new types of phosphorus binders^18,19, vitamin D analogs, and calcimimetics in China. New non - calcium phosphate binders, such as sevelamer, can effectively control serum phosphorus levels without increasing serum calcium, thus reducing the risk of cardiovascular complications²⁰. The 2019 Clinical Practice Guideline of Chronic Kidney Disease – Mineral and Bone Disorder (CKD - MBD) in China recommends non - calcium phosphate binders as first - line agents for managing hyperphosphatemia in CKD patients without hypocalcemia. Cinacalcet, the first calcimimetic drug, was introduced to China in 2015 and has since become a valuable treatment option for patients with secondary hyperparathyroidism (SHPT). More recent calcimimetics like etelcalcetide have demonstrated significant efficacy in lowering PTH levels and improving SHPT outcomes in dialysis patients. In addition, biologics targeting fibroblast growth factor 23 (FGF − 23) and Klotho are currently under investigation, potentially offering innovative treatment strategies for SHPT²¹. Thirdly, there is a need to enhance treatment adherence. Patients often struggle to adhere to complex treatment regimens, which may involve multiple medications and dietary restrictions. Educational initiatives are also necessary to boost understanding of the condition and its treatment. The management of CKD - MBD typically requires a multidisciplinary approach, involving nephrologists, endocrinologists, nutritionists, and other specialists. Nevertheless, fragmented care can result in disjointed management plans. To address these unmet needs, a multifaceted approach is required, including improving access to care, enhancing education, developing new treatment options, ensuring patients have the necessary support to effectively manage their condition, and conducting further research.

The high rate of arteriovenous fistula use in China is a positive finding, as it aligns with the ‘fistula first’ principle and is associated with better patient outcomes. We must also focus on the timing of first vascular access for HD patients. It is our recommendation to create a fistula prior to initiating HD, particularly during the transition phase for patients with advanced CKD.

The study has several limitations. Firstly, data was collected only from three major cities, which may not be representative of the entire HD population in China. Patients in smaller cities and rural areas may have different medical conditions and treatment outcomes. The insurance coverage and economic conditions in smaller cities and rural areas may differ from those in large cities as well, potentially affecting the frequency and quality of dialysis treatments patients receive. Secondly, due to the limitations in data collection, there may be selection bias that could affect the generalizability of the study results.

Above all, we provided an understanding of current profile for Chinese HD patients, and addressed regional differences. Our goal is to provide comprehensive care that not only focuses on the dialysis treatment itself but also on the broader health needs of the patient to improve their quality of life and survival outcomes. Our results offering insights into the patient demographics and the potential service requirements for this healthcare cohort. We suggest healthcare providers and policymakers can work towards improving the health outcomes for all patients.

Acknowledgements

The Dialysis Outcomes and Practice Patterns Study (DOPPS) Program in China is supported by Vifor Fresenius Renal Pharma, Sanofi Renal, Nipro Trading (Shanghai) Co., Ltd., 3SBio Inc., B. Braun, CEMMA MEDICAL, and Kyowa Kirin China Pharmaceutical Co., Ltd.

Author contributions

Conception and design of research: Xinju Zhao and Li Zuo; analyzed data: Xinju Zhao, Chengqian Ma, Xue Li and Wudong Guo; interpreted results of experiments: Xinju Zhao and Li Zuo; prepared figures: Xinju Zhao; drafted manuscript: Xinju Zhao; edited and revised manuscript: Liangying Gan, Fan Fan Hou, Xinling Liang, Zhaohui Ni, Xiaonong Chen, Yuqing Chen, and Li Zuo; approved final version of manuscript: Li Zuo.

Funding

This study was supported by Beijing Natural Science Foundation [No.7222201] and Research Project of Blood Purification Center Branch of Chinese Hospital Association (No. CHABP2021-11), the grant recipients are Li Zuo, and Xinju Zhao, respectively.

Data availability

The data used of this study are available from the corresponding author on reasonable request.

Declarations

Competing interests

The authors declare no competing interests.

Ethical approval

The study was approved by the Ethics Committee of Peking University People’s Hospital (ethical approval number: 2018PHB028-01). Other participating sub-centers also obtain ethics committee approval documents prior to the start of clinical trials.

Consent form

All patients signed the written informed consent.

Publisher’s note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

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