Dong Chan Jin1, Jin Suk Han2. 1. Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Seoul, Korea. 2. Department of Internal Medicine, College of Medicine, Seoul National University, Seoul, Korea.
Abstract
The Korean Society of Nephrology (KSN) launched the official end-stage renal disease (ESRD) patient registry in 1985, and an Internet online registry program was opened in 2001 and revised in 2013. The ESRD Registry Committee of KSN has collected data on dialysis therapy in Korea through the online registry program in the KSN Internet website. The status of renal replacement therapy in Korea at the end of 2012 is described in the following. The total number of ESRD patients was 70,211 at the end of 2012, which included 48,531 hemodialysis (HD) patients, 7,552 peritoneal dialysis (PD) patients, and 14,128 functioning kidney transplant (KT) patients. The prevalence of ESRD was 1,353.3 patients per million population (PMP), and the distribution of renal replacement therapy among ESRD patients was as follows: HD, 69.1%; PD, 10.8%; and KT, 20.2%. The number of new ESRD patients in 2012 was 11,742 (HD, 8,811; PD, 923; and KT, 1,738; the incidence rate was 221.1 PMP). The primary causes of ESRD were diabetic nephropathy (50.6%), hypertensive nephrosclerosis (18.5%), and chronic glomerulonephritis (18.1%). The mean urea reduction ratio was 67.9% in male and 74.1% in female HD patients. The mean Kt/V was 1.382 in male and 1.652 in female HD patients. The 5-year survival rates of male and female dialysis patients were 70.6% and 73.5%, respectively.
The Korean Society of Nephrology (KSN) launched the official end-stage renal disease (ESRD) patient registry in 1985, and an Internet online registry program was opened in 2001 and revised in 2013. The ESRD Registry Committee of KSN has collected data on dialysis therapy in Korea through the online registry program in the KSN Internet website. The status of renal replacement therapy in Korea at the end of 2012 is described in the following. The total number of ESRDpatients was 70,211 at the end of 2012, which included 48,531 hemodialysis (HD) patients, 7,552 peritoneal dialysis (PD) patients, and 14,128 functioning kidney transplant (KT) patients. The prevalence of ESRD was 1,353.3 patients per million population (PMP), and the distribution of renal replacement therapy among ESRDpatients was as follows: HD, 69.1%; PD, 10.8%; and KT, 20.2%. The number of new ESRDpatients in 2012 was 11,742 (HD, 8,811; PD, 923; and KT, 1,738; the incidence rate was 221.1 PMP). The primary causes of ESRD were diabetic nephropathy (50.6%), hypertensive nephrosclerosis (18.5%), and chronic glomerulonephritis (18.1%). The mean urea reduction ratio was 67.9% in male and 74.1% in female HDpatients. The mean Kt/V was 1.382 in male and 1.652 in female HDpatients. The 5-year survival rates of male and female dialysis patients were 70.6% and 73.5%, respectively.
The Korean Society of Nephrology (KSN) has the largest continuous end-stage renal disease (ESRD) patient registry, established in 1985, in which all KSN members are participating voluntarily: the “Insan Prof. Min Memorial ESRDPatient Registry.”The objectives and importance of the patient registry and statistical evaluation of ESRD can be summarized as follows: (1) to estimate the numbers and distributions of target therapy patients by a dialysis specialist group (KSN); (2) to know the characteristics of ESRD and dialysis therapy, and its complications or results based on scientific evidence; and (3) to improve the quality of dialysis therapy, and provide information on socioeconomic health administration and the future health plan.In 2013, because vascular access and dialysis quality became more important, KSN ESRD Committee has revised the online registry program. Newly included items were vascular access, dialysate components, calcium and phosphorous control, and rehabilitation status [1].
Data collection method
The ESRD Registry Committee of KSN has collected data on dialysis centers and patients through an online registry program on the KSN Internet website (http://www.ksn.or.kr) launched in 2001 and revised the program in 2013. The program also has a graphic evaluation function of dialysis adequacy [Kt/V and normalized protein catabolic rate (nPCR)] and a peritoneal equilibrium test. For ensuring the security of patients’ personal information, the program was accessible only to designated dialysis staff with a hospital code and password. Information on nonresponding dialysis centers was collected through questionnaires sent by mail.
Data on dialysis therapy in Korea
Prevalence and incidence of ESRD in Korea
At the end of 2012, in Korea, the number of overall ESRDpatients was 70,211, and that of ESRDpatients under maintenance hemodialysis (HD), peritoneal dialysis (PD), and with functioning transplanted kidney were 48,531, 7,552, and 14,128, respectively. The prevalence per million population (PMP) was 935.4 for HD, 145.6 for PD, 272.3 for kidney transplantation (KT), and 1,353.3 for overall ESRD (Figs. 1A, 1B). These ESRD prevalence rates are slightly higher than those in most European countries, but about 60% of those in the United States and about 40% of those in Japan, according to the international comparison data of the annual United States renal data report [2], [3], [4]. The annual increase in the prevalence rate was about 10% during 2000–2012.
Figure 1
Prevalence and incidence of end-stage renal replacement therapy in Korea. The number of patients with renal replacement therapy at the end of each year (A); point prevalence of renal replacement therapy (B); patients starting renal replacement therapy each year (C); and three major causes of end-stage renal disease (D). CGN, chronic glomerulonephritis; DM, diabetic nephropathy; HD, hemodialysis; HTN, hypertensive nephrosclerosis; KT, kidney transplantation; PD, peritoneal dialysis; PMP, patient numbers per million population; RRT, renal replacement therapy.
The number of new patients undergoing renal replacement therapy in 2012 was 11,472 (221.1 PMP). The number of new ESRDpatients with HD, PD, and KT were 8,811 (169.8 PMP), 923 (17.8 PMP), and 1,738 (33.5 PMP), respectively (Fig. 1C). The number of new patients with PD has been decreasing since 2007, whereas those with HD and KT have been increasing continuously; this is consistent with the trend observed in the United States [2].The most common causes of ESRD in new patients were diabetic nephropathy, hypertensive nephrosclerosis, and chronic glomerulonephritis (50.6%, 18.5%, and 8.1%, respectively; Table 1). Among these three underlying diseases, the incidence of diabetic nephropathy increased rapidly during 1990–2000 (Fig. 1D). The proportion of diabetic nephropathy in ESRDpatients in Korea was one of the highest in the world, which was similar to some Asian countries and the United States [2].
Table 1
Causes of end-stage renal diseases in new patients
Causes
%
1992
1994
1996
1998
2000
2002
2004
2006
2008
2009
2010
2011
2012
Chronic glomerulonephritis
25.3
25.5
21.6
17.9
14.0
13.9
12.5
13.0
12.1
11.1
11.3
10.4
8.1
Not histologically confirmed
19.7
20.4
16.7
13.6
10.6
10.0
8.6
9.0
8.2
7.5
7.7
6.9
4.5
Histologically confirmed
5.6
5.0
4.9
4.3
3.4
3.9
3.9
3.9
3.8
3.6
3.6
3.5
3.6
Diabetic nephropathy
19.5
26.1
30.8
38.9
40.7
40.7
43.4
42.3
41.9
45.4
45.2
47.1
50.6
Hypertensive nephrosclerosis
15.4
20.8
18.3
17.8
16.6
16.0
16.2
16.9
18.7
18.3
19.2
19.6
18.5
Cystic kidney disease
2.1
2.2
1.8
1.7
2.2
1.6
1.4
1.7
1.7
1.8
1.7
1.6
1.8
Renal tuberculosis
1.1
1.5
1.2
0.5
0.4
0.5
0.3
0.3
0.2
0.2
0.2
0.2
0.0
Pyelo/interstitial nephritis
1.3
1.1
0.7
1.0
0.8
0.6
0.6
0.6
0.5
0.5
0.4
0.4
0.5
Drugs or nephrotoxic agents
1.3
0.1
0.6
0.3
0.3
0.4
0.2
0.3
0.3
0.3
0.3
0.5
0.4
Lupus nephritis
0.8
0.7
1.0
0.5
0.9
0.8
0.6
0.6
0.6
0.6
0.5
0.5
0.6
Gouty nephropathy
0.7
0.7
0.6
0.5
0.7
0.4
0.5
0.3
0.3
0.3
0.4
0.2
0.3
Hereditary nephropathy
0.3
0.7
0.4
0.2
0.1
0.2
0.3
0.3
0.3
0.2
0.2
0.2
0.5
Kidney tumor
0.1
0.1
0.2
0.2
0.2
0.3
0.3
0.2
0.2
0.2
0.2
0.3
0.3
Other
4.1
2.7
2.8
3.9
3.0
5.6
5.9
6.0
5.8
5.2
5.1
5.0
6.8
Uncertain
28.6
17.8
15.9
16.6
20.2
19.0
17.8
17.5
17.6
16.0
15.3
14.3
11.4
Renal replacement therapy modalities
Approximately 77% of new ESRDpatients in 2012 started HD as their initial renal replacement therapy, whereas approximately 8% started PD. The prevalence rates of HD, PD, and KT were 69%, 11%, and 20%, respectively (Fig. 2A).
Figure 2
Renal replacement therapy modalities. Proportion of renal replacement modalities (annual prevalence and incidence in 2012) (A); the numbers of hemodialysis centers and hemodialysis machines (B), and hemodialysis patients and hemodialysis patients per hemodialysis machine (C); percent distribution of hemodialysis patients according to dialysis center classification (D); and regional distribution of dialysis patients in Korea (E). HD, hemodialysis; KT, kidney transplantation; PD, peritoneal dialysis.
The numbers of HD centers and HD machines have also been increasing rapidly in Korea. At the end of 2012, Korea had 691 HD centers and 18,901 HD machines (Fig. 2B). The ratio of machines per center was about 27, and that of patients per machine was 2.6 (Fig. 2C). Approximately one-third of maintenance HDpatients were admitted to university hospitals in the late 1990s, but currently, about 46% of HDpatients are treated in private dialysis clinics (Fig. 2D).An analysis of the distribution of ESRDpatients according to the zones in Korea showed that approximately 50% of HDpatients and more than 50% of PDpatients were located in the capital area (Fig. 2E).
Dialysis patient demographics
The gender ratio of dialysis patients was 57.5% male and 42.5% female in HD therapy and 56.1% male and 43.9% female in PD therapy (Fig. 3A).
Figure 3
Dialysis patient demographics. Gender ratio of HD and PD patients according to year (A); ABO blood type and hepatitis virus of HD and PD patients (B); age distribution of dialysis patients according to dialysis modalities (C), years (D), and underlying diseases (E); duration of maintenance HD and PD versus percent of estimated patient number according to year (F); duration of dialysis maintenance in diabetic and nondiabetic patients (G); distribution of BMI (H) and mean blood pressure (I) in HD and PD patients (blood pressure is higher in HD patients than in PD patients); and systolic and diastolic blood pressures with pulse pressure in HD and PD patients (J). BMI, body mass index; BP, blood pressure; DM, diabetic patients; HD, hemodialysis; HTN, hypertensive nephrosclerosis; GN, glomerulonephritis; MBP, mean blood pressure; PD, peritoneal dialysis.
The ABO blood type distribution of dialysis patients was type A, 34%; type B, 27%; type AB, 12%; type O, 27%, which was not different from the general population. Hepatitis B virus antigen was positive in 6% of dialysis patients and hepatitis C virus antibody in 4% (Fig. 3B).The mean age of dialysis patients was 59.2±14.1 years. The age distribution of dialysis patients showed two peaks, one at the age of 50 years and the other at the age of 65 years (Fig. 3C), indicating that at least two or more different disease groups are present among ESRDpatients. The age distribution according to year since 1986 showed that the peak age has been shifting to older age and the current peak age is in the 60s (Fig. 3D). The percentage of dialysis patients aged more than 65 years increased to up to 37.5% of overall dialysis patients in 2012.The age distribution according to underlying diseases showed that the peak age of chronic glomerulonephritis was 53.7 years and that of diabetic nephropathy was 61.8 years (Fig. 3E).About 45% of HDpatients and 44% of PDpatients had been undergoing dialysis for more than 5 years; these percentages had increased from 30% and 14%, respectively, in 2001 (Fig. 3F).Approximately 53% of nondiabetic HDpatients had been undergoing dialysis for more than 5 years, whereas only 35% of diabetic HDpatients had been undergoing dialysis for the same period. Similarly, approximately 49% of nondiabetic PDpatients and 34% of diabetic PDpatients had been undergoing dialysis for more than 5 years (Fig. 3G).The mean body mass index was 22.1±3.4 kg/m2 in HDpatients and 24.2±3.7 kg/m2 in PDpatients; this showed a steady increase in both HD and PD groups. In HDpatients, the mean body mass index was 22.6±3.5 kg/m2 in diabeticpatients and 21.7±3.2 kg/m2 in nondiabeticpatients (Fig. 3H).The mean blood pressures were similar between HD and PDpatients (99.7±12.5 mmHg and 98.0±12.8 mmHg, respectively; Fig. 3I), but the pulse pressure was much higher in HDpatients than in PDpatients (64.2 mmHg vs. 52.2 mmHg, Fig. 3J). Although the blood pressure of dialysis patients is decreasing, the pulse pressure of HDpatients is increasing; this might be associated with the risk of cardiovascular morbidity.
Characteristics of HD, PD, and erythropoietin therapy
HD frequency, dialyzer, and dialysate
Most HDpatients received dialysis three times per week (Fig. 4A) since 2000 (91.3% in 2012). Hemodiafiltration therapy was performed in 11% of HDpatients, but 53% of HDpatients received dialysis with a dialyzer having a surface area of less than 1.5 m2 (Fig. 4B). Mostly bicarbonate and standard calcium (3.0 mEq/L) with glucose dialysate were used (Fig. 4C).
Figure 4
Characteristics of HD, PD, and erythropoietin therapy. Frequency of hemodialysis per week (A); percent of HDF-applied patients and dialyzer membrane surface area (B); hemodialysis dialysate (C); vascular access for HD (D); PD catheter type and PD catheter insertion methods (E); Distribution of peritoneal dialysis types and doses (percentage) (F); changes in hemoglobin level in dialysis patients, HD versus PD (note the increase of hemoglobin in HD patients) (G); percent distribution of erythropoietin doses prescribed for HD and PD patients (H); distribution of patients numbers according to calcium and phosphorous levels (I); PTH levels of HD and PD patients (x-axis is on nature logarithmic scale) (J); phosphate binders and PTH control medications (K); distribution of URR in hemodialysis patients (L); dialysis adequacy parameters (nPCR and spKT/V) in HD patients (M); dialysis adequacy parameters (spKt/V) in diabetic and nondiabetic HD patients (N); and distribution of patient numbers according to nPCR and spKt/V in HD patients (O) and according to nPNA and Kt/V in PD patients (P). APD, automated peritoneal dialysis; AVF, arteriovenous fistula; CAPD, continuous ambulatory peritoneal dialysis; EPO, erythropoietin; Hct, hematocrit; HD, hemodialysis; HDF, hemodiafiltration; nPCR, normalized protein catabolic rate; nPNA, normalized protein nitrogen appearance; PD, peritoneal dialysis; PTH, parathyroid hormone; spKt, single-pool Kt/V; URR, urea reduction ratio.
Vascular access for HD
Of the HDpatients, 79% had autologous arteriovenous fistula, of which 50% was in the left forearm, and 14% had graft fistula (Fig. 4D).
PD catheter and dialysate dose
Of the PDpatients, 48% had swan neck PD catheters and 23% had straight PD catheters. The PD catheter was inserted surgically in 62% of PDpatients. The break-in period after catheter insertion was mostly 2–3 weeks, for both surgical and trochar insertions (Fig. 4E). Automated PD therapy was applied to 24% of PDpatients, and a PD dialysate volume of 10–12 L/day was used in 48% of PDpatients (Fig. 4F).
Anemia and erythropoietin therapy
In 2012, the mean hemoglobin level of HDpatients was 10.4±1.1 g/dL and that of PDpatients was 10.2±1.3 g/dL (Fig. 4G). Although, theoretically, PDpatients have a lower prevalence of anemia than HDpatients, the recent use of erythropoietin therapy has increased hemoglobin levels in HDpatients more than in PDpatients. This therapeutic result is shown clearly in Figs. 4G and 4H: Of the HDpatients, 46% were injected with 8,000 or more units of erythropoietin per week, whereas only 33% of PDpatients were injected with this level of erythropoietin and 19% of PDpatients were not injected with erythropoietin. The significant increase in the hemoglobin level of both dialysis patients in 2004 and 2005 was due to an increase in the reimbursement level of hemoglobin by the National Health Insurance.
Laboratory data and medications
The distribution of patient numbers according to calcium and phosphorous levels is shown in Fig. 4I; the mean total calcium and phosphorous levels in HDpatients were 8.88±0.89 mg/dL and 5.14±1.64 mg/dL, respectively. Serum intact parathyroid hormone level of dialysis patients has been shown as a nature logarithmic scale distribution (Fig. 4J).Calcium bicarbonate or acetate was used in 67% HDpatients as a phosphate binder, and 24% of HDpatients received vitamin D therapy (Fig. 4K).The mean serum albumin, creatinine, cholesterol, uric acid, and HbA1c levels in HDpatients were 3.9 g/dL, 9.68 mg/dL, 144.0 mg/dL, 7.22 mg/dL, and 6.92%, respectively.
Dialysis adequacy
The mean urea reduction ratio was 67.9% in male and 74.1% in female HDpatients (Fig. 4L). This gender difference of dialysis adequacy resulted from the use of similar dialysis doses in men and women despite a body mass difference between the genders. The overall mean urea reduction ratio was 70.5±7.1%; which showed a steady increase.The average nPCR and single-pool Kt/V were 0.98±0.28 and 1.49±0.29, respectively. Similar to the urea reduction ratio, both these values were higher in women than in men (Fig. 4M). Single-pool Kt/V was higher in nondiabeticpatients than in diabeticpatients, presumably because of the quality of vascular access for dialysis (Fig. 4N). The recent protein catabolic rate showed a slight decrease, presumably because of the increase in the proportion of elderly dialysis patients.Distribution of patient numbers according to nPCR and single-pool Kt/V in case of HDpatients and that according to nPNA and PD Kt/V in case of PDpatients are shown in Figs. 4O and 4P.
Rehabilitation, morbidities, causes of death, and survival rates of dialysis patients
Rehabilitation
Of the PDpatients, 33% had full-time jobs and 24% part-time jobs, but only 24% of HDpatients had full-time jobs in 2012 (Fig. 5A). This means that a higher rehabilitation rate was achieved in PDpatients.
Figure 5
Rehabilitation, morbidities, causes of death, and survival rates of dialysis patients. Rehabilitation status of HD and PD patients in 2012 (A); comparison of causes of death in HD versus PD patients in 2001–2012 (B); overall survival of dialysis patients registered since 2001 (C); survival of HD and PD patients since 2001 (D); and patient survival according to underlying diseases since 2001 (E). DM, diabetic nephropathy; GN, glomerulonephritis; HD, hemodialysis; HTN, hypertensive nephrosclerosis; Misc, miscellaneous; PD, peritoneal dialysis.
Comorbidity
The most common complications (51.2%) in HDpatients were vascular diseases, which included hypertension, cerebrovascular accident, and other vascular diseases (Table 2). Furthermore, 60.7% of PDpatients had vascular diseases, and the infectious complication rate was higher in PDpatients (8.5%) than in HDpatients (5.0%).
The causes of death in dialysis patients in a descending order of frequency were cardiac causes, infection, and vascular disease. The cause of death was unknown or miscellaneous in one-quarter of dialysis patients (Table 3, Fig. 5B). Some year-to-year variation was observed because of limitations in death reports.
Table 3
Causes of death (%) in dialysis patients, 1994–2012⁎
The overall 1- and 5-year survival rates of dialysis patients were 95% and 72%, respectively (Fig. 5C). These survival rates were higher than those observed in the United States and Japan [2], [3], but the Korean survival rate was calculated only from the data of dialysis patients registered since 2001. The Korean ESRD Registry covers only about two-thirds of all dialysis patients in Korea because registry enrollment is voluntary.The 5-year survival rate was higher in HDpatients than in PDpatients (72.6% vs. 68.3%; Fig. 5D), and the 5-year survival rate was higher for chronic glomerulonephritispatients than for diabeticpatients (86.4% vs. 61.4%; Fig. 5E).
Kidney transplantation
In 2012, KT was performed in 1,783 cases, which included 768 deceased donors (Fig. 6). The KT rate was 37 cases per 1,000 dialysis patients, which was below the world average [2]. However, the waiting number has been increasing sharply, and 12,463 surviving dialysis patients were enrolled in the Korean Network of Organ Sharing waiting list at the end of 2012.
Figure 6
Annual number of KTs in Korea (including data from the KONOS). Surviving KT waiting patient number at the end of each year. KONOS, Korean Network for Organ Sharing; KT, kidney transplantation.
Conclusion
The increasing proportion of elderly and diabeticpatients in the Korean population has resulted in a rapid increase in the number of ESRDpatients, which reached 1,353 PMP at the end of 2012. A high proportion of diabetic ESRDpatients (50.6%) and a decrease in the proportion of PDpatients were observed recently. Among ESRDpatients, the proportion of HD has increased to 69%, PD decreased to 11%, and KT has remained at 20%. The adequacies of dialysis and anemia therapy have been improving steadily in Korea.
Conflicts of interest
The authors have no potential conflicts of interest relevant to this article.
Authors: Jin Suk Kang; Hee Ryeong Jang; Jeong Eun Lee; Young Joo Park; Harin Rhee; Eun Young Seong; Ihm Soo Kwak; Il Young Kim; Dong Won Lee; Soo Bong Lee; Sang Heon Song Journal: Clin Exp Nephrol Date: 2015-07-30 Impact factor: 2.801