감염 예방을 위한 인공신장실 의료 환경에 대한 고찰 - 근거 기반의 디자인 중심으로

한수하 ( Han Su Ha ),윤형진 ( Yoon Hyungjin ) 한국의료복지건축학회(구 한국의료복지시설학회) 2018 의료·복지 건축 Vol.24 No.3

Purpose: The increase in patients requiring hemodialysis has resulted in an increase dialysis-associated infections risk. but there are no Renal Dialysis unit design standard meet specified safety and quality standards. Therefore, appropriate Establish standards and legal regulation is important for the provision of initial certification and maintenance of facility, equipment, and human resource quality. Methods: Literature survey on the design guideline and standards of Renal Dialysis unit design in Korea, U.S, Germany, Singapore, Hongkong, Dubai. Results: There are no established standards for facilities in dialysis units in Korea. To prevent infections in dialysis patients, necessary establish standards. Considering the domestic and overseas Health-care facilities standards, the major factors to be considered in the medical environment for Renal Dialysis Unit are as follows. First, planning to separate Clean areas(treatment area) from contaminated areas(medical waste storage area). Second, ensure sufficient space and minimum separation distance. Although there may be differences depending on the circumstances of individual institutions, renal dialysis unit consider the space to prevent droplet transmission. Third, secure infrastructure of infection prevention such as sufficient amount of hand hygiene sinks. Hand washing facilities for staff within the Unit should be readily available. Hand hygiene sinks should be located to prevent water from splashing into the treatment area. Fourth, Heating, ventilation and air conditioning (HVAC) system for Renal Dialysis Unit is all about providing a safer environment for patients and staff. Implications: The results of this paper can be the basic data for the design of the Renal Dialysis Units and relevant regulations.

The Incidences and Characteristics of Various Cancers in Patients on Dialysis: a Korean Nationwide Study

권순길,한정호,김혜영,강길원,강민석,Yeonkook J. Kim,민진수 대한의학회 2019 Journal of Korean medical science Vol.34 No.25

Background: The numbers of patients on dialysis and their life expectancies are increasing. Reduced renal function is associated with an increased risk of cancer, but the cancer incidence and sites in dialysis patients compared with those of the general population require further investigation. We investigated the incidences of various cancers in dialysis patients in Korea and used national health insurance data to identify cancers that should be screened in dialysis clinics. Methods: We accessed the Korean National Health Insurance Database and excerpted data using the International Classification of Disease codes for dialysis and malignancies. We included all patients who commenced dialysis between 2004 and 2013 and selected the same number of controls via propensity score matching. Results: A total of 48,315 dialysis patients and controls were evaluated; of these, 2,504 (5.2%) dialysis patients and 2,201 (4.6%) controls developed cancer. The overall cancer risk was 1.54-fold higher in dialysis patients than in controls (adjusted hazard ratio, 1.71; 95% confidence interval, 1.61–1.81). The cancer incidence rate (incidence rate ratio [IRR], 3.27) was especially high in younger dialysis patients (aged 0–29 years). The most common malignancy of end-stage renal disease patients and controls was colorectal cancer. The major primary cancer sites in dialysis patients were liver and stomach, followed by the lung, kidney, and urinary tract. Kidney cancer exhibited the highest IRR (6.75), followed by upper urinary tract (4.00) and skin cancer (3.38). The rates of prostate cancer (0.54) and oropharyngeal cancer (0.72) were lower than those in the general population. Conclusion: Dialysis patients exhibited a higher incidence of malignancy than controls. Dialysis patients should be screened in terms of colorectal, liver, lung, kidney and urinary tract malignancies in dialysis clinics.

장기 투석 환자에서 발생한 신세포암의 임상적 특성

김영옥 ( Kim Yeong Og ),한창희 ( Han Chang Hui ),신옥란 ( Sin Og Lan ),윤정민 ( Yun Jeong Min ),신석준 ( Sin Seog Jun ),장윤경 ( Jang Yun Gyeong ),윤선애 ( Yun Seon Ae ),양철우 ( Yang Cheol U ),진동찬 ( Jin Dong Chan ),김용수 ( Ki 대한신장학회 2003 Kidney Research and Clinical Practice Vol.22 No.5

배 경 : 장기간 투석을 받고 있는 말기 신부전증 환자에서 신세포암의 발생빈도는 정상인에 비해 매우 높은 것으로 알려져 있다. 그러나 국내에서는 이에 대한 연구가 보고되어 있지 않다. 이에 장기 투석 환자에서 발생하는 신세포암의 임상적 특성을 알아보고자 하였다. 방 법 : 1993년 1월부터 2002년 12월까지 10년 동안 혈액투석 혹은 복막투석을 받고 있는 환자에서 발생한 신세포암을 후향적으로 조사하였다. 투석 전에 신세포암이 발생한 증례는 대상에서 제외 하였다. 결 과 : 총 7예의 신세포암이 발견되었다. 대상 환자의 평균 연령은 46±9세였으며 남자 6명 여자 1명이었다. 원인 신질환은 만성 사구체 신장염과 상염색체 우성 다낭신이 각각 3예였고 고혈압성 신증이 1예였다. 전체 7명의 환자 중 5명이 혈액투석 환자였고 나머지 2명이 복막투석 환자였다. 평균 투석기간은 82±46개월이었다. 신세포암 발견시 주요 증세는 2예에서는 전혀 증세가 없이 우연히 발견되었으며 3예에서는 측복부 동통이었고 2명에서는 복부 종괴의 촉진이었다. 전 환자에서 복부 전산화 단층촬영이 시행되었으며 종양의 크기는 평균 3.1±1.9 ㎝이었으며 상염색체 우성 다낭신 이외의 환자에서도 모두 다수의 낭종이 관찰되었다. 측복부 동통을 호소한 3명 모두는 신낭종의 자연 파열로 인한 신주위 혈종으로 신적출술 후 시행한 조직검사에서 신세포암이 우연히 발견되었다. 3명의 낭종 파열 환자 중 2명은 상염색체 우성 다낭신 환자였다. TNM 분류법에 의한 종양의 병기는 6예가 1기였고 나머지 1예는 폐에 전이된 4기였다. 1기의 6예는 모두 신적출술을 받았으며 평균 45±35개월의 추적기간 동안 1명의 환자에서 신세포암과 무관한 간질환으로 사망하였고 5명의 환자는 재발 없이 투석을 받고 있다. 결 론 : 장기 투석 환자에서 발생하는 신세포암은 대부분이 조기에 발견되었으며 이러한 환자에서는 신적출술의 예후가 양호하였다. 또한 신세포암은 모두 유전성 혹은 후천성 신낭종과 관련 되어 있었으며 평균 투석기간이 82±46개월로 길었다. Background : The incidence of renal cell carcinoma (RCC) in patients receiving long-term hemo-dialysis or peritoneal dialysis patients is 100-fold higher than that in general population. But the clinical study about RCC in dialysis patients is not reported in Korea yet. This study was performed to evaluate the clinical characteristics of RCC in dialysis patients. Methods : We retrospectively investigated medical records of dialysis patients who were diagnosed with RCC between patients January, 1993 and December, 2002. RCC diagnosed before first dialysis was excluded. Diagnosis of RCC was made by both radio-logic and pathologic examinations. Results: A total of 7 patients was diagnosed with RCC. Mean age was 46±9 years. Primary renal disease consisted of chronic glomerulonephritis (n=3), autosomal dominant polycystic kidney disease (n=3), and hypertensive nephropathy (n=l). Five patients were on hemodialysis, 2 were on peritoneal dialysis. Mean duration of dialysis was 82±46 months. The presenting symptoms were asymptomatic in 2 patients, sudden onset of flank pain due to spontaneous renal cyst rupture in 3, palpable abdominal mass in 2. Mean tumor size was 3.1±1.9 cm and multiple renal cysts were noted in all patients. According to the TNM classification for RCC, 6 patients had stage I and 1 patients had stage IV. Six patients with stage I were treated with nephrectomy. With a mean follow-up of 45235 months after the operation, there has been no recurrence. Conclusion : Six patients out of total 7 patients had early stage tumor and all these patients were treated with nephrectomy and the prognosis was good. All RCC were associated with inherited or acquired multiple renal cysts.

REVIEW : Major changes and improvements of dialysis therapy in Korea: review of end-stage renal disease registry

( Dong Chan Jin ) 대한내과학회 2015 The Korean Journal of Internal Medicine Vol.30 No.1

The Korean Society of Nephrology (KSN) launched a nationwide end-stage renal disease (ESRD) patient registry in 1985 called the Insan Prof. Byung-Suk Min Memorial ESRD Patient Registry. KSN members voluntarily participate in this registry, which has been collecting data through the Internet since 2000. The KSN ESRD patient registry data were reviewed to elucidate the major changes and improvements in dialysis therapy in Korea. The data review revealed: a rapid increase in the number of patients with ESRD; an increase in the number of patients with diabetic nephropathy; a decrease in the proportion of patients undergoing peritoneal dialysis; an increase in the role of private dialysis clinics; an increase in the number of elderly patients undergoing dialysis and the number of patients undergoing long-term dialysis; a decrease in mean blood pressure and an increase in pulse pressure; improvement in anemia treatment; improvement in dialysis adequacy; and improvement in the survival of patients undergoing dialysis. In conclusion, improvements have been made in blood pressure control, anemia treatment, and dialysis adequacy despite increases in the number of elderly patients, diabetic patients, and patients on long-term dialysis during the last two decades in Korea.

The impact of high-flux dialysis on mortality rates in incident and prevalent hemodialysis patients

( Hyung Wook Kim ),( Su Hyun Kim ),( Young Ok Kim ),( Dong Chan Jin ),( Ho Chul Song ),( Euy Jin Choi ),( Yong Lim Kim ),( Yon Su Kim ),( Shin Wook Kang ),( Nam Ho Kim ),( Chul Woo Yang ),( Yong Kyun 대한내과학회 2014 The Korean Journal of Internal Medicine Vol.29 No.6

Background/Aims: The effect of high-flux (HF) dialysis on mortality rates could vary with the duration of dialysis. We evaluated the effects of HF dialysis on mortality rates in incident and prevalent hemodialysis (HD) patients. Methods: Incident and prevalent HD patients were selected from the Clinical Research Center registry for end-stage renal disease (ESRD), a Korean prospective observational cohort study. Incident HD patients were defined as newly diagnosed ESRD patients initiating HD. Prevalent HD patients were defined as patients who had been receiving HD for > 3 months. The primary outcome measure was all-cause mortality. Results: This study included 1,165 incident and 1,641 prevalent HD patients. Following a median 24 months of follow-up, the mortality rates of the HF and low- flux (LF) groups did not significantly differ in the incident patients (hazard ratio [HR], 1.046; 95% confidence interval [CI], 0.592 to 1.847; p = 0.878). In the prevalent patients, HF dialysis was associated with decreased mortality compared with LF dialysis (HR, 0.606; 95% CI, 0.416 to 0.885; p = 0.009). Conclusions: HF dialysis was associated with a decreased mortality rate in prevalent HD patients, but not in incident HD patients.

혈액투석 환자의 악력, 혈압, 투석적절도, 투석증상 및 우울 간의 관계

김창희,문선숙 한국재활간호학회 2022 재활간호학회지 Vol.25 No.2

Purpose: This study aimed to determine relationships among handgrip strength (HGS), blood pressure, dialysis adequacy, dialysis symptoms, and depression in hemodialysis patients. Methods: Data from 150 subjects were obtained and analyzed, following a descriptive approach. Results: The average grip strength of the subjects was lower than the standard value for both men and women, and the grip strength differed significantly according to age, gender, education level, monthly income, and BMI. The physiological indicators that showed significant results with the study variables were hemoglobin, serum calcium, and serum phosphorus. The average dialysis adequacy (Kt/V) of the subjects was higher than the normal standard, and there were significant differences according to age, gender, education level, monthly income, dialysis period, number of accompanying diseases, and BMI. The subject's depression score had a significant negative correlation with dialysis adequacy, and the dialysis symptom score and depression score had a significant positive correlation. Conclusion: General characteristics, dialysis-related characteristics, and physiological indicators of hemodialysis patients were analyzed in detail, and differences between these characteristics and grip strength, blood pressure, dialysis adequacy, dialysis symptoms, and depression were also examined. It is necessary to provide delicate nursing according to the individual characteristics of the patient.

단일 기관에서 장기 치료한 복막투석과 혈액투석 환자의 치료 경과 비교

김정민 ( Jeong-min Kim ),이세진 ( Se-jin Lee ),서동균 ( Dong-kyun Seo ),이기영 ( Ki-young Lee ),류상열 ( Sang Ryol Ryu ),이소영 ( So-young Lee ) 대한내과학회 2017 대한내과학회지 Vol.92 No.1

목적: 투석을 시작한지 3년이 지났으며 잔여 신기능이 없어졌다고 생각되는 환자들의 혈액투석 치료와 복막투석 치료 간의 치료 경과를 비교하였다. 대상 및 방법: 을지병원에서 36개월 이상 투석 치료를 받는 투석 환자를 대상으로 하였다. 대상 환자들의 의무기록을 조사하였고, 검사실 소견을 평균하여 기록하였다. 투석 적절도와 체수분량을 측정하였고 염증성 사이토카인을 측정하여 치료 방법에 따른 차이를 비교하였다. 결과: 총 80명의 환자 중 복막투석 환자 39명, 혈액투석환자 41명이었고 두 군 간에 평균 연령, 남녀비에는 차이가 없었다. 혈액투석 환자의 경우 97.5%의 환자가 Kt/V 1.2 이상을 만족하였으나 복막투석 환자의 경우 58%만이 이 기준을 만족하였다. 복막투석 환자가 더 BMI가 높았고 중성지방 수치가 높았으며 저밀도콜레스테롤이 높은 경향을 보였고 두군 간의 수분 조절 상태에 큰 차이는 없었다. 염증 수치는 Kt/V가 1.7 미만, 저투과도를 보이는 복막투석 환자군에서 더 의미 있게 높게 측정되었다. 결론: 장기 복막투석 환자의 경우, 혈액투석에 비해 효율적인 투석 적절도 유지가 어렵다. 이러한 투석 효율의 감소가 복막투석 환자를 상대적인 과염증 상태에 이르게 하는 원인이 될 수 있다고 생각된다. 따라서 장기 복막투석 환자의 경우, 투석 효율을 높이고 관리가 철저히 이루어질 수 있도록 환자 교육과 의료진의 관심이 더욱 필요한 치료군이라고 생각된다. Background/Aims: Improvements in dialysis therapies and patient care are leading to more patients receiving dialysis for longer periods of time. Survival rates with peritoneal dialysis (PD) are superior to those with hemodialysis (HD) during the initial 2-3 years; however, data comparing the outcomes of these two methods are lacking. Thus, we performed a retrospective study of patients treated with dialysis for longer than 3 years to investigate patient condition according to mode of dialysis. Methods: A total of 80 patients currently being treated by dialysis for at least 36 months at the Eulji Medical Center were included in this study. Patients` laboratory data and admissions histories over the prior 3 years were reviewed. Dialysis adequacy, body composition, and cytokine levels were quantified. Results: A total of 39 PD and 41 HD patients, with no difference in mean age or gender, were compared. Regarding dialysis adequacy, 97.5% of HD patients met the criterion of 1.2 Kt/V or higher, whereas only 58% of PD patients satisfied the required weekly Kt/V of 1.7. Inflammatory cytokines were significantly elevated in PD patients; however, PD patients with adequate dialysis expressed the same inflammatory cytokines as HD patients. Conclusions: The delivery of adequate dialysis to PD patients over extended periods of time is difficult. Thus, more rigorous management of PD patients is required to avoid insufficient dialysis and inflammation. (Korean J Med 2017;92:45-52)

Age, diabetes mellitus, and dialysis modality are associated with risk of poor muscle strength and physical function in hemodialysis and peritoneal dialysis patients

( Maryanne Zilli Canedo Silva ),( Karina Jesus Antonio ),( João Marcos Soares Reis ),( Leticia Salmazzo Alves ),( Jacqueline Costa Teixeira Caramori ),( Barbara Perez Vogt ) 대한신장학회 2021 Kidney Research and Clinical Practice Vol.40 No.2

Background: Due to the poor outcomes associated with the impairment of physical function and muscle strength in patients on maintenance dialysis, it is important to understand the factors that may influence physical function and muscle strength. The aim of this study was to explore the factors associated with physical function in hemodialysis and peritoneal dialysis patients. Methods: Patients with chronic kidney disease on dialysis for at least 3 months, aged 18 years old or above, were enrolled. Physical function was assessed by handgrip strength, gait and sit-to-stand tests, and the Short Physical Performance Battery (SPPB). Clinical and laboratory data were collected to verify the association with physical function parameters through binary logistic regression. Results: One-hundred ninety patients on maintenance dialysis were included; 140 patients (73.7%) on hemodialysis and 50 (26.3%) on peritoneal dialysis. The mean age was 57.3 ± 14.9 years, 109 (57.4%) were male, and 87 (45.8%) were older than 60 years. The median SPPB was 8.0 points (6.0-10.0 points) and the mean ± standard deviation of handgrip strength was 24.7 ± 12.2 kg. Binary logistic regression showed that age, type of renal replacement therapy, diabetes mellitus, and serum creatinine were significantly associated with both higher 4-meter gait test times and lower SPPB scores. Only age and diabetes mellitus were associated with higher sit-to-stand test times, while age and ferritin were associated with lower handgrip strength. Conclusion: Age, diabetes mellitus, serum creatinine, and hemodialysis modality are factors related to physical function in dialysis patients.

Break - in Period 동안 시행한 혈액 투석이 지속성 외래 복막 투석 환자의 잔여 신기능에 미치는 영향

박진아(Ji Nah Park),김대중(Dae Joong Kim),정시정(Shi Jung Chung),한혁준(Hyeok Jun Han),허우성(Woo Seong Huh),김윤구(Yoon Goo Kim),오하영(Ha Young Oh) 대한신장학회 2001 Kidney Research and Clinical Practice Vol.20 No.1

복막 투석 도관 삽입 후, 도관 및 수술 부위에 관련된 합병증을 줄이기 위하여 도관 삽입 2주내지 4주 후 복막 투석을 시작하도록 권유하고 있고, 이 기간을 break -in period라고 한다. 일부 환자에서 이 기간 동안 유지 혈액 투석을 하게 되는 경우가 있다. 잔여 신기능이 혈액 투석을 하는 환자보다 복막 투석 환자에서 잘 보존되는 것으로 알려져 있으므로, 혈액 투석을 거치지 않고 복막 투석을 직접 시작한 환자에 비해 break-in period동안 혈액 투석을 한 환자에서 잔여 신기능이 더 감소할 것으로 예상된다. 이에 저자들은 지속성 외래 복막 투석 환자에서 break-in period동안에 시행한 혈액 투석이 잔여 신기능에 미치는 영향을 알아보기 위하여 이 연구를 시작하였다. 1999년 3월 이후 지속석 외래 복막 투석을 시작하고 임상적으로 안정적인 20명의 환자를 대상으로 하였다. 6명의 환자에서 1개월의 break-in period동안 혈액 투석을 시행하였고, 그 후 지속성 외래 복막 투석을 시작하였다(A군). 14명의 환자에서는 1개월, 3개월, 6개월 후에 사구체 여과율(소변에서 측정한 요소 청소율과 크레아티닌 청소율의 평균)과 소변에서의 요소 제거율(urine Kt/V)을 측정하였다. 잔여 신기능과의 상관관계를 보기 위한 변수로 평균 동맥혈압, 혈청 알부민, 혈색소, 적혈구 용적율, 연령, 성별, 당뇨병의 유무, 복막염의 발생을 관찰하였다. 신대체 요법 시작 시점에서 두 군의 평균 동맥혈압, 혈청 알부민, 혈색소, 적혈구 용적율, 연령, 성별 당뇨병의 유무는 통계학적인 차이는 없었다. 신대체 요법 시작 시점의 사구체 여과율은 A군이 B군보다 낮았으나(A군: 45.0±10.1L/week, B군: 54.6±5.7L/week), 통계학적인 차이는 없었다. 신대체 요법을 시작한 뒤 1개월 후 측정한 사구체 여과율은 B군에서는 변화가 별로 없었으나 A군에서는 현저히 감소하여 두 군 사이에 유의한 차이를 보였고(A군: 28.6±5.3L/week, B군: 54.4±5.7L/week), 이 차이는 6개월 시점까지 지속되었다. 사구체 여과율과 소변에서의 요소 제거율의 변화는 평균 동맥혈압, 혈청 알부민, 혈색소, 적혈구 용적율과 상관관계가 없었으며, 성별이나 당뇨병의 유무, 복막염의 빈도등에 의해 영향을 받지 않았다. Break-in periond의 혈액 투석은 잔여 신기능의 감소를 가져왔고 이는 신대체 요법후 6개월까지도 회복되지 않았다. 이에 저자들은 지속성 외래 복막 투석을 시행할 환자의 경우 적절한 시기에 도관을 삽입하여 혈액 투석에 의한 잔여 신기능의 감소를 피하는 것이 바람직할 것으로 생각하였다. To avoid later complication of peritoneal dialysis catheter, it is recommended to delay regular exchange of peritoneal dialysis for about 2-4weeks after insertion of catheter(break-in period). During break-in period some patients need hemodialysis(HD) or other intermittent dialysis. In such cases residual renal function(RRF) can decrease substantially compared with patients who do not need HD during break-in period since RRF is preserved better in CAPD patients than HD patients. This is prospective observational study to examine such an effect of HD during break-in period on residual renal function in CAPD patients. 20 patients who were clinically stable and had been on CAPD since March, 1999 were observed. 6 patients were treated with HD for 1month during break-in period and CAPD thereafter(group A). 14 patients were treated with CAPD without HD(group B). GFR(mean of creatinine and urea clearance of urine) and urine Kt/V urea were measured at start, and 1, 3, 6 months of renal replacement therapy. Covariables analyzed in this study were mean arterial blood pressure, serum albumin, hemoglobin, hematocrit, age, sex, the presence of diabetes mellitus, and peritonitis episode. There was no significant difference in initial RRF, mean arterial blood pressure, serum albumin, hemoglobin, hematocrit, age, sex, and the presence of diabetes mellitus between 2 groups. Initial GFR was a little smaller in group A than group B(45.0±10.1 L/week vs. 54.6±5.7L/week) which was not statistically significant. GFR after 1, 3 and 6months of dialysis(including 1month of HD in group A) were smaller in group A than B(28.6±5.3L/week vs. 54.4±5.7L/week, 32.7±5.2L/week vs 56.9±6.1Lweek, 21.0±4.1L/week vs 53.6±5.4L/week at 1,3,6 months after dialysis in group A and B), which were significant. Urine Kt/V showed same pattern. The change of GFR and urine Kt/V have no correlation with serum albumin, hemoglobin, hematocrit, and change of mean arterial blood pressure and is not affected by sex, and presence of DM or peritonitis. We concluded that HD during break-in period can decrease RRF in CAPD patients, which may not recover after 6months of dialysis. Avoiding HD during break-in period with appropriate preparation can preserve RRF in CAPD patients.

크레메진의 투석도입 지연효과에 따른 진행성 신부전증환자의 비용감소분 추계

조우현,이선미,김형종,이호영,우태욱,강혜영,Cho, Woo-Hyun,Lee, Sun-Mi,Kim, Hyung-Jong,Lee, Ho-Yong,Woo, Tae-Wook,Kang, Hye-Young 대한예방의학회 2006 예방의학회지 Vol.39 No.2

Objectives : We wanted to evaluate the economic value of a pharmaceutical product, Kremezin, for treating patients with chronic renal failure (CRF) by estimating the amount of cost savings due to its effect for delaying the initiation of dialysis treatments. Methods : We defined a conventional treatment for CRF accompanied by Kremezin therapy as 'the treatment group' and only conventional treatment as 'the alternative group.' The types of costs included were direct medical and nonmedical costs and costs of productivity loss. The information on the effect of Kremezin was obtained from the results of earlier clinical studies. Cost information was derived from the administrative data for 20 hemodialysis and 20 peritoneal dialysis patients from one tertiary care hospital, and also from the administrative data of 10 hemodialysis patients from one free-standing dialysis center. Per-capita cost savings resulting from Kremezin therapy were separately estimated for the cases with delay for the onset of hemodialysis and the cases with immediate performance of peritoneal dialysis. By computing the weighted average for the cases of hemodialysis and peritoneal dialysis, the expected per-capita cost savings of a patient with CRF was obtained. Using a discount rate of 5%, future cost savings were converted to the present value. Results : The present value of cumulative cost savings per patient with CRF from the societal perspective would be $18,555,000{\sim}29,410,000$ Won or $72,104,000{\sim}112,523,000$ Won if Kremezin delays the initiation of dialysis by 1 or 4 years. Conclusions : The estimated amount of cost savings resulting from treating CRF patients with Kremezin confirms that its effect for delaying the onset of dialysis treatments has a considerable economic value.