Cutaneous abnormalities in uremic patients

Pathogenesis and Treatment of Pruritus Associated with Chronic Kidney Disease and Cholestasis

Itching is an unpleasant sensation that provokes the desire to scratch. In general, itching is caused by dermatologic diseases, but it can also be caused by systemic diseases. Since itching hampers patients' quality of life, it is important to understand the appropriate treatment and pathophysiology of pruritus caused by systemic diseases to improve the quality of life. Mechanisms are being studied through animal or human studies, and various treatments are being tested through clinical trials. We report current trends of two major systemic diseases: chronic kidney disease and cholestatic liver disease. This review summarizes the causes and pathophysiology of systemic diseases with pruritus and appropriate treatments. This article will contribute to patients' quality of life. Further research will help understand the mechanisms and develop new strategies in the future.

Uremic pruritus: pathophysiology, clinical presentation, and treatments

Uremic pruritus is one of the most common and bothersome symptoms in patients with end-stage renal disease. Most patients with uremic pruritus experience a prolonged and relapsing course and significant impairments of quality of life. The pathophysiology of uremic pruritus is not completely understood. A complex interplay among cutaneous biology and the nervous and immune systems has been implicated, with the involvement of various inflammatory mediators, neurotransmitters, and opioids. Uremic pruritus treatment outcomes are often unsatisfactory. Clinical trials have mostly been small in scale and have reported inconsistent results. Recent evidence shows that gabapentinoids, nalfurafine, and difelikefalin are effective for relieving uremic pruritus in hemodialysis patients. This review provides an overview of the epidemiology and proposed mechanisms of uremic pruritus, then highlights the manifestations of and clinical approach to uremic pruritus. Current evidence regarding treatment options, including topical treatments, treatment of underlying disease, phototherapy, and systemic treatments, is also outlined. With a better understanding of uremic pruritus, more therapeutic options can be expected in the near future.

Pruritus in Continuous Ambulatory Peritoneal Dialysis and Hemodialysis Patients

To study the prevalence and pathogenesis of uremic pruritus, CAPD and HD patients were asked to complete a questionnaire. The replies were quantitated based on numerical scales, and the results were compared with various hematological and biochemical parameters, underlying disease, and duration of dialysis. There were 113 CAPD patients (63 males and 50 females), mean age 60 (range 20–84) years, average time on CAPD 20 (range 1–163) months and 76 HD patients (44 males and 32 females) mean age 57 (range 23–81) years, mean time on HD 44 (range 2–242) months. Replies to questions were evaluated and graded by the same Investigator who did not know the patients.

Pruritus was present in 70 (62%) CAPD patients (64% in females and 600/0 in males p=NS) and in 41 (54%) HD patients (69% in females and 43% in males, p=0.025). Before starting dialysis pruritus was present in 30% CAPD patients and 28% HD patients. Pruritus was graded as mild, moderate and severe; the distribution was 58.6%, 34.3%, and 7.1% (CAPD) and 43.90/0, 41.5%, and 14.6% (HD), respectively. Dry skin was reported by 73% CAPD patients and 72% HD patients.

This xerodermia was correlated with the severity of pruritus and was also present In 65% CAPD and 48.5% HD patients without pruritus. Patients with pruritus were older than those without pruritus both for CAPD (63 vs 54 years, p=0.004) and HD (61 vs 51 years, p=0.003). A significant correlation was observed only between pruritus score and age for CAPD patients. There were no other correlations between pruritus and the other parameters studied.

We conclude that pruritus Is a frequent symptom In dialysis patients, but It Is severe only In a small proportion. Its prevalence, as also that of dry skin, Increases after start of dialysis and Is higher In females on HD.

Patients with pruritus are older, and the severity of pruritus correlates with age in the CAPD patients. Presence of dry skin correlates with severity of pruritus, and Its prevalence Is high even among patients without pruritus.

Prognostic importance and determinants of uremic pruritus in patients receiving peritoneal dialysis: A prospective cohort study

Background

Uremic pruritus is a common and frustrating symptom among patients receiving peritoneal dialysis (PD). This study aimed to examine the prognostic importance of uremic pruritus and to identify the determinants for higher pruritus intensity in PD patients.

Methods

We conducted a prospective cohort study of patients receiving maintenance PD. A visual analogue scale (VAS) score was used to measure the intensity of uremic pruritus. The composite endpoint of PD technique failure or all-cause death was assessed using a multivariable Cox proportional hazards model. The determinants for the VAS score of uremic pruritus was assessed using a multivariable linear regression model.

Results

Among the 85 PD patients, 24 (28%) had uremic pruritus. During a median follow-up of 28.0 months, 12 patients experienced technique failure, and 7 died. We found that a higher VAS score of pruritus intensity was an independent risk factor for technique failure or death (hazard ratio, 1.64; 95% confidence interval, 1.18 to 2.28; P = 0.003) after adjusting for a variety of confounding factors. We also found that a weekly total Kt/V of less than 1.88, a longer duration of dialysis, a higher dietary protein intake, and higher blood levels of intact parathyroid hormone and high-sensitivity C-reactive protein were independent determinants of higher VAS scores of pruritus intensity.

Conclusions

Our results show that uremic pruritus is an independent risk factor of technique failure and death in patients receiving PD. We also found that a weekly total Kt/V < 1.88 is associated with higher intensity of uremic pruritus in PD patients.

A randomized controlled trial for effectiveness of zolpidem versus acupressure on sleep in hemodialysis patients having chronic kidney disease-associated pruritus

BACKGROUND

Pruritus adds to the complications of chronic kidney disease (CKD) patient and a well-recognized complication among the CKD patients. Majority of the patients on hemodialysis experience a generalized pruritus and patients reported being moderately to extremely disturbed by at least one of the sleep-related condition. This study aim to investigate the effectiveness of zolpidem 10 mg and acupressure therapy on foot acupoints to improve the sleep quality and overall quality of life among hemodialysis patients suffering from CKD-associated pruritus.

METHODS

A multicentered, open-label, parallel group, prospective randomized controlled trial among patients suffering from CKD-associated pruritus with sleep disturbance, after randomization into control, and intervention group to be held at North West General Hospital and Research Center Peshawar, Pakistan and Institute of Kidney Diseases Peshawar, Pakistan.

RESULTS

The primary outcome is to investigate the effectiveness of zolpidem 10 mg and acupressure therapy on foot acupoints to improve the sleep quality and overall quality of life among hemodialysis patients suffering from CKD-associated pruritus. After baseline assessment by Urdu version of 5D itch scale and Urdu version of Pittsburgh Sleep Quality Index (PSQI) and Urdu EQ-5D 3L, the intervention group will be given zolpidem 10 mg oral tablets and control group with acupressure on both foots on KI-1 acupoints for total of 6 minutes. Assessment will be done at weeks 4 and 8 from baseline by using Urdu version of 5D itch scale and Urdu version of PSQI and Urdu EQ-5D 3L, whereas safety profiling of zolpidem 10 mg tablet at week 6 from baseline and acupressure acceptability at week 6 from baseline. Analysis of covariance will be used to examine the differences in treatment effects between the intervention and control groups.

CONCLUSION

Improvement of sleep quality and quality of life among patients with CKD-associated pruritus requires great importance. This study aims to improve the quality of sleep and quality of life among patients with hemodialysis suffering from CKD-associated pruritus.

Risk of Skin Diseases in Maintenance Hemodialysis

INTRODUCTION

Maintenance hemodialysis (HD) patients are potential transplant recipients. One of the most common cancers in the population of kidney recipients is skin neoplasm. Skin infections are also of a particular importance. In this population, especially in patients on the transplant waiting list, full dermatological examination, including dermatoscopy, should be carried out routinely.

MATERIALS AND METHODS

The research was comprised of 105 HD patients (57 men, 48 women) with a mean age of 60.8 (range 25-94) years. The patients' skin condition was assessed and a dermatoscopic examination was performed. We compared the incidence of skin diseases in the two subpopulations: HD patients (n = 89) and HD patients active on the transplant waiting list (n = 16).

RESULTS

Bacterial, fungal, and viral infections in the group of HD patients occurred in 24.7%, 14.6%, and 6.7% of patients, respectively. In HD patients on the waiting list, bacterial skin diseases were reported in 12.5% of patients, and neither fungal nor viral infections were noticed. Malignant skin lesions and precancerous conditions, such as basal cell carcinoma and keratosis actinic, developed in 4.5% and 3.4% of the HD patients. These malignancies did not occur in HD patients on the waiting list. The results show proper qualification for transplantation in maintenance HD patients before the waiting list. In the group of dialysis patients, 67.4% required dermatological care, while in the HD waiting group only 12.5% required dermatological care.

CONCLUSIONS

The presented results prove the necessity of performing dermatological examinations on HD patients. Some dermatological skin lesions, if not diagnosed and treated, could progress to cancer after organ transplantation.

Omega-3 Supplementation Improves Pruritus in Continuous Ambulatory Peritoneal Dialysis Patients: A Crossover Randomized Pilot Clinical Trial

Objective:

Pruritus is a prevalent skin condition in end-stage renal disease patients. Omega-3 fatty acids have been shown to reduce pruritus in hemodialysis patients. Our objective was to assess the effect of 3 g/day omega-3 supplementation on pruritus among continuous ambulatory peritoneal dialysis (CAPD) patients.

Methods:

In this two-period, two-sequence crossover randomized clinical trial, 40 eligible subjects (CAPD patients who complained of pruritus for more than 8 weeks) were randomized to 3 g of omega-3 (n = 20) or identical placebo capsules (n = 20) for 4 weeks. After a wash-out period of 6 weeks, patients were crossed over to the alternate treatment option. Pruritus intensity was assessed using the visual analog scale (VAS) at baseline, 2-and 4-weeks post-intervention in each study period. Both patients and investigators were blinded to the study protocol.

Findings:

No significant carry-over effect was detected. The mean pruritus score (VAS) in the omega-3 group compared with placebo group after the first (−3.02 vs. −0.48, P < 0.001) and second (−4.09 vs. −0.43, P < 0.001) intervention periods showed higher significant decrease.

Conclusion:

In summary, omega-3 supplementation is an effective treatment for pruritus alleviation in CAPD patients. Further studies are needed to determine the mechanisms underlying antipruritic effects of omega-3.

Translation of the 5D Itching Scale from English to Malay, and Its Validation among Patients with Chronic Kidney Disease in Malaysia

Introduction

Several tools have been developed to assess the severity of pruritus. In Malaysia, no tool has been validated to assess pruritus in patients with chronic kidney disease (CKD). Therefore, the aim of our study was to validate the Malay 5D itching scale (M5D-IS) among patients with CKD in Malaysia.

Method

The English version of the 5D-IS was translated into Malay according to International Guidelines. Face and content validity was determined by an expert panel and pilot tested in patients with end-stage renal disease (ESRD). The M5D-IS was then validated in a tertiary hospital in Malaysia from May to June 2016. We recruited patients with (i.e., patients with ESRD) and without pruritus (i.e., patients with stage 1–3 CKD) (to determine if the M5D-IS could discriminate between the two groups), and administered the M5D-IS at baseline and 2 weeks later. Exploratory factor analysis was used to examine the construct validity. Internal consistency was assessed using Cronbach’s alpha and intraclass correlation coefficient was calculated to assess the reliability of the instrument.

Results

A total of 70 participants were recruited (response rate = 100%). The majority were males (51.4%) and Malay (67.1%). Exploratory factor analysis revealed that the 5D-IS had 2-factor loadings: “daily routine activity” and “pattern of itching,” which explained 77.7% of the variance. The overall score of the M5D-IS, as well as for each domain, was significantly worse in participants with pruritus (9.83 ± 0.35), compared to those without pruritus (5.51 ± 0.93, p < 0.001). The overall Cronbach’s alpha for the M5D-IS was (0.861), indicating adequate internal consistency. At test–retest, the intraclass correlation coefficient was significantly correlated.

Conclusion

The M5D-IS was found to be a valid and reliable instrument to assess pruritus among patients with CKD in Malaysia.

Validity and reliability of the Urdu version of the 5D itching scale to assess pruritus among patients with chronic kidney disease in Pakistan

Background

Chronic kidney disease (CKD) has become a major public health issue worldwide in the past few years. Pruritus is a common, well-recognized complication often seen in patients with chronic renal failure. For assessment of pruritus, different tools are used but these tools are unable to identify the changes and variations in the severity of pruritus. The aim of our study was to validate the Urdu-version of the Urdu-version of the 5D itch scale among patients suffering from chronic kidney disease in Pakistan.

Method

The 5D itch scale was translated from English into Urdu following translation guidelines for translation. Face and content validity was determined by a panel of experts and piloted. For retest, the Urdu version of the 5D itch scale was administered at baseline and two weeks.

Results

A total of 50 participants with end stage renal disease were recruited, and of these, 64% were males. Exploratory factor analysis revealed that the 5D–IS had 2-factor loadings: “Pattern and activity” and “Distribution” with Kaiser–Mayer–Olkin (KMO) = 0.802, Bartlett’s test of sphericity was significant (df = 28, p < 0.001). At test re-test, Cronbach’s alpha was 0.914, while the intra class correlation was 0.9160 (95% confidence interval 0.941–0.975), which is a highly significant correlation (p < 0.0001).

Conclusion

The Urdu version of the 5D itch scale was found to be a valid and reliable instrument for assessing pruritus and its severity in patients with chronic kidney disease in Pakistan.

Electronic supplementary material

The online version of this article (10.1186/s12882-017-0717-0) contains supplementary material, which is available to authorized users.

Bone marrow-derived cells and their conditioned medium induce microvascular repair in uremic rats by stimulation of endogenous repair mechanisms

The reduced number of circulating stem/progenitor cells that is found in chronic kidney disease (CKD) patients may contribute to impaired angiogenic repair and decreased capillary density in the heart. Cell therapy with bone marrow-derived cells (BMDCs) has been shown to induce positive effects on the microvasculature and cardiac function, most likely due to secretion of growth factors and cytokines, all of which are present in the conditioned medium (CM); however, this is controversial. Here we showed that treatment with BMDC or CM restored vascular density and decreased the extent of fibrosis in a rat model of CKD, the 5/6 nephrectomy. Engraftment and differentiation of exogenous BMDCs could not be detected. Yet CM led to the mobilization and infiltration of endogenous circulating cells into the heart. Cell recruitment was facilitated by the local expression of pro-inflammatory factors such as the macrophage chemoattractant protein-1, interleukin-6, and endothelial adhesion molecules. Consistently, in vitro assays showed that CM increased endothelial adhesiveness to circulating cells by upregulating the expression of adhesion molecules, and stimulated angiogenesis/endothelial tube formation. Overall, our results suggest that both treatments exert vasculoprotective effects on the heart of uremic rats by stimulating endogenous repair mechanisms.

Comparison of the incidence of skin cancers in patients on dialysis and after kidney transplantation

INTRODUCTION

Kidney transplant (KTx) patients on immunosuppressive therapy are predisposed to the development of infections and cancers.

AIM

To compare the incidence and type of malignant skin lesions in kidney transplant patients and the dialyzed population based on the initiated dermatologic screening.

MATERIAL AND METHODS

The study included 598 patients: 486 kidney transplant recipients and 112 patients on maintenance dialysis. All the patients underwent dermatological examination. Only histologically confirmed cancers were included in this study. Age, gender and immunosuppressive therapy administration were also considered. Patients were followed up by a dermatologist for a period of 5 years.

RESULTS

Fifty-eight skin cancers; 39 basal cell carcinomas (BCC), 13 squamous cell carcinomas (SCC), 1 Bowen disease, 2 Kaposi sarcoma, 1 malignant melanoma, 1 Merkel cell carcinoma, and 1 fibrosarcoma protuberans were diagnosed in 30 (6.2%) kidney transplant patients, and 8 lesions (7 BCC and 1 SCC) were found in 4 (3.6%) patients on dialysis.

CONCLUSIONS

The initiated dermatologic screening program indicates that the risk of skin cancer incidence in post kidney transplant patients receiving immunosuppressive therapy was significantly higher than in patients on dialysis.

An Observational Longitudinal Study Investigating the Effectiveness of 75 mg Pregabalin Post-Hemodialysis among Uremic Pruritus Patients

A prospective, observational, longitudinal study was conducted to assess the effectiveness of 75 mg pregabalin (PG) post-hemodialysis (pHD) for treatment-resistant uremic pruritus (UP). A total of forty-five patients completed the entire six week follow-up. At the baseline assessment, the majority of the patients were distressed by the UP frequency and intensity. Sleep (mean = 3.30 ± 1.1), leisure/social activities (mean = 2.90 ± 0.80) and distribution (mean = 2.92 ± 0.34) were the three domains that were primarily effected by the UP. Overall, further reduction in the 5D-itching scale (IS) was noted at day 42, which confirmed a sustained (B = -12.729, CI -13.257 to -12.201, p < 0.001) relief of pruritus severity among patients with treatment-resistant pruritus. Patients with a higher serum calcium level had a score difference of +1 from the other patients (B = 1.010, p = 0.061). There was a reduction of 12 points compared to the baseline 5D-IS for each patient on day 42 after using pregabalin 75 mg PD pHD for 42 days, which represented major relief. Among the demographic factors, only gender was significantly associated with the 5D-IS score.

Nonsteroidal Antiinflammatory Drug-Induced Pseudoporphyria: A Case Series

Background:

Pseudoporphyria is a diagnosis that is used when porphyria-like clinical lesions arise in the setting of normal porphyrin levels. This condition was first described in the 1960s and was initially related to the use of certain antibiotic drugs. In 1985, pseudoporphyria was first attributed to the use of nonsteroidal antiinflammatory drugs (NSAIDs). Subsequently, a host of NSAIDs and other drugs have been found to elicit the same clinical entity. The exact mechanism by which certain drugs create clinical lesions resembling porphyria cutanea tarda or erythropoietic protoporphyria is still unknown. A phototoxic mechanism is hypothesized.

Objective:

We describe six patients diagnosed with pseudoporphyria and detail the diagnostic tests leading to the eventual diagnosis.

Results:

The patients ranged in age from 27 to 59 years and had a female:male predominance of 2:1. The offending NSAID was DayPro (oxaprozin) for three of the patients, Relafen (nabumetone) for two of the patients, and Aleve (naproxen) for one patient. For each patient, histology and immunofluorescence was either consistent with the diagnosis of porphyria cutanea tarda or nonspecific, while serum, stool, and urine porphyrins did not support that diagnosis. Withdrawal of the offending agent provided relief from the clinical symptoms for each patient. None of our patients were rechallenged with the putative offending drug. However, prolonged avoidance has provided a sustained remission from symptoms in all six patients.

Conclusions:

Pseudoporphyria is a relatively rarely reported condition. Clinical suspicion with appropriate laboratory and histopathologic findings help to make this diagnosis, and exclude true porphyrias. Rechallenge with the offending drug to produce symptom relapse has been proposed to be helpful in confirming this diagnosis of exclusion. Since all 6 patients with drug-induced pseudoporphyria experienced resolution of their symptoms after discontinuing the offending agent, we propose that this clinical correlation alone is sufficient to confirm this diagnosis. Our observation of six new cases of NSAID-induced pseudoporphyria over a two-year interval suggests that this is not a rare entity.

Do Patients With End-Stage Chronic Renal Failure Treated With the Use of Hemodialysis Have Healthy Skin? Evaluation of Skin Lesions and Basic Education About Risk Factors for Skin Cancer in This Patient Population

BACKGROUND

Considering the increasing incidence of skin cancers in patients after renal transplantation, evaluation of skin condition in dialysis patients, from whom kidney transplant recipients are recruited, appears to be very important. Particular importance is attached to the identification of such dialysis patients in the population who require dermatologic care before qualifying for transplantation. The objective of this study was to determine the prevalence of skin diseases in the dialysis patient population. Education of the patients regarding risk factors for skin cancer and the need for sun protection was performed.

METHODS

Full dermatologic examination, including dermatoscopy, was performed on a group of 77 dialysis patients (38 women, 39 men) and a control group of 77 healthy people (60 women, 17 men).

RESULTS

Eight hemodialysis patients had healthy skin compared with 33 people from the control group. In the remaining hemodialysis patients, the following skin lesions were observed: 1) inflammatory and allergic skin disorders in 17 patients; 2) bacterial, fungal, and viral infections in 26 patients; 3) benign lesions in 39 patients; 4) malignant skin lesions and precancerous conditions in 4 patients; and 5) other skin changes in 63 patients.

CONCLUSIONS

Skin lesions are common in the dialysis patient population. Only 10% of the examined population had completely healthy skin, compared with 43% of the control group. More than one-half of dialysis patients required dermatologic care compared with one-third of healthy control subjects.

Pruritus in Kidney Disease

Pruritus is a common and distressing symptom in patients with chronic kidney disease. The most recent epidemiologic data have suggested that approximately 40% of patients with end-stage renal disease experience moderate to severe pruritus and that uremic pruritus (UP) has a major clinical impact, being associated strongly with poor quality of life, impaired sleep, depression, and increased mortality. The pathogenesis of UP remains largely unclear, although several theories on etiologic or contributing factors have been proposed including increased systemic inflammation; abnormal serum parathyroid hormone, calcium, and phosphorus levels; an imbalance in opiate receptors; and a neuropathic process. UP can present somewhat variably, although it tends to affect large, discontinuous, but symmetric, areas of skin and to be most symptomatic at night. A variety of alternative systemic or dermatologic conditions should be considered, especially in patients with asymmetric pruritus or other atypical features. Treatment initially should focus on aggressive skin hydration, patient education on minimizing scratching, and optimization of the aspects of chronic kidney disease care that are most relevant to pruritus, including dialysis adequacy and serum parathyroid hormone, calcium, and phosphorus management. Data for therapy specifically for UP remain limited, although topical therapies, gabapentin, type B ultraviolet light phototherapy, acupuncture, and opioid-receptor modulators all may play a role.

[Cutaneous manifestations in patients on chronic hemodialysis in a developing country]

Our study aims to highlight the most common skin disorders in patients on chronic hemodialysis at the University Hospital Yalgado Ouédraogo (CHU-YO) in Ouagadougou. The study, of transverse type descriptive, carried out of September 15 to December 31, 2014, is unrolled with the CHU-YO. This descriptive transversal study was conducted at the CHU-YO from September 15 to December 31, 2014. It involved patients who had been on chronic dialysis for at least 3 months. The frequency of hemodialysis sessions was one every five days. The significance level of statistical tests was defined as the probability p ≤ 0.05. Eighty-five patients (61.1% men and 38.9% women) with an average age of 42.1 years were included in the study. The mean duration of hemodialysis was 31.9 months. The success rate of biological examinations varied from 7,4 to 85,3%. Eighty patients (85,3%) had at least one cutaneous manifestation. Cutaneous xerosis (67.4%), pruritus (45.3%), and hyperpigmentation (23.2%) were the most frequent skin manifestations that may be specific of hemodialysis. Guttate hypomelanosis (11.6%), prurigo (11.6%) and folliculitis (8.4%) were the main non-specific skin manifestations. Skin involvement was frequent but did not seem related to seniority in hemodialysis. In Ouagadougou, bad hemodialysis conditions and a hot, dry environment promote such conditions, especially xerosis and pruritus. A better subvention of health care could help to reduce the prevalence of skin diseases and to improve the quality of life of our patients on chronic hemodialysis.

A Comparison of Uremic Pruritus in Patients Receiving Peritoneal Dialysis and Hemodialysis

Uremic pruritus is common and bothersome in patients receiving either peritoneal dialysis (PD) or hemodialysis (HD). To date, the preferred dialysis modality regarding the alleviation of uremic pruritus remains controversial. We conducted this cross-sectional study to compare the prevalence, intensity, and characteristics of uremic pruritus between PD and HD patients. Patients receiving maintenance dialysis at a referral medical center in Taiwan were recruited. Dialysis modality, patient demographic, clinical characteristics, and laboratory data were recorded. The intensity of uremic pruritus was measured using visual analogue scale (VAS) scores. Multivariate linear regression analysis was conducted to compare the severity of uremic pruritus between PD and HD patients. Generalized additive models were applied to detect nonlinear effects between pruritus intensity and continuous covariates. A total of 380 patients completed this study, with a mean age of 60.3 years and 49.2% being female. Uremic pruritus was presented in 24 (28.6%) of the 84 PD patients and 113 (38.2%) of the 296 HD patients (P = .12). The VAS score of pruritus intensity was significantly lower among the PD patients than the HD patients (1.32 ± 2.46 vs 2.26 ± 3.30, P = .04). Multivariate linear regression analysis showed that PD was an independent predictor for lower VAS scores of pruritus intensity compared with HD (β-value -0.88, 95% confidence interval -1.62 to -0.13). The use of active vitamin D was also an independent predictor for a lower intensity of uremic pruritus, whereas hyperphosphatemia and higher serum levels of triglyceride and aspartate transaminase were significantly associated with higher pruritus intensity. There was a trend toward a less affected body surface area of uremic pruritus in the PD patients than in the HD patients, but the difference did not reach statistical significance (P = .13).In conclusion, the severity of uremic pruritus was lower among PD patients than HD patients, and PD may provide better alleviation of pruritus symptoms. The result provides a valuable reference for clinicians and patients when choosing a dialysis modality.

Epidemiology and determinants of pruritus in pre-dialysis chronic kidney disease patients

PURPOSE

There are only a few small studies investigating chronic kidney disease-associated pruritus (CKD-P) in pre-dialysis chronic kidney disease (CKD). None of these has taken into account the associations of CKD-P with clinical features and laboratory data. We aimed to study prevalence of and clinical and laboratory associates of CKD-P in pre-dialysis CKD patients.

METHODS

A total of 402 consecutive stage 2-5 pre-dialysis CKD patients were included in this cross-sectional study. Pruritus was scored based on visual analog scale (VAS). Demographic and clinical features, comorbidities, smoking status and current medication use were recorded. 25 (OH) Vitamin D, urea, creatinine, uric acid, calcium, phosphorus, intact parathyroid hormone (PTH), magnesium, albumin, C-reactive protein (CRP), complete blood count and differential and other laboratory tests were studied for each participant.

RESULTS

This is the largest study conducted in pre-dialysis population with respect to pruritus and associated factors. The prevalence of CKD-P was 18.9%. Hemoglobin level was significantly lower, and eosinophil count and frequency of xerosis cutis were significantly higher in patients with CKD-P than those of patients without pruritus. However, there was no statistical difference between the pruritus and nonpruritus groups regarding vitamin D, PTH, calcium, phosphorus, neutrophil-to-lymphocyte ratio (NLR) and CRP.

CONCLUSIONS

CKD-P was almost present in one in every five pre-dialysis CKD patients. Interestingly, the prevalence was not affected by the stage of the CKD. For the first time, our results showed a significant association between CKD-P and peripheral eosinophilia and anemia. Besides this, xerosis cutis seems a determinant factor for CKD-P and its severity.

Pruritus epidemiology and quality of life

The burden of chronic pruritus is increasingly recognized as significant worldwide. As wet-laboratory researchers investigate the pathophysiology of chronic pruritus, epidemiologists and health services researchers are quantifying the impact of pruritus by incidence, prevalence, and quality of life measures. Outcomes researchers are also investigating factors that may predict chronic pruritus incidence and severity. Such efforts will direct resources for research, public health intervention, and clinical care.

Executive summary of the KDIGO Controversies Conference on Supportive Care in Chronic Kidney Disease: developing a roadmap to improving quality care

Patients with advanced chronic kidney disease (CKD) have a high burden of physical and psychosocial symptoms, poor outcomes, and high costs of care. Current paradigms of care for this highly vulnerable population are variable, prognostic and assessment tools are limited, and quality of care, particularly regarding conservative and palliative care, is suboptimal. The KDIGO Controversies Conference on Supportive Care in CKD reviewed the current state of knowledge in order to define a roadmap to guide clinical and research activities focused on improving the outcomes of people living with advanced CKD, including those on dialysis. An international group of multidisciplinary experts in CKD, palliative care, methodology, economics, and education identified the key issues related to palliative care in this population. The conference led to a working plan to address outstanding issues in this arena, and this executive summary serves as an output to guide future work, including the development of globally applicable guidelines.

Soluble Flt-1 links microvascular disease with heart failure in CKD

Chronic kidney disease (CKD) is associated with an increased risk of heart failure (HF). Elevated plasma concentrations of soluble Flt-1 (sFlt-1) have been linked to cardiovascular disease in CKD patients, but whether sFlt-1 contributes to HF in CKD is still unknown. To provide evidence that concludes a pathophysiological role of sFlt-1 in CKD-associated HF, we measured plasma sFlt-1 concentrations in 586 patients with angiographically documented coronary artery disease and renal function classified according to estimated glomerular filtration rate (eGFR). sFlt-1 concentrations correlated negatively with eGFR and were associated with signs of heart failure, based on New York Heart Association functional class and reduced left ventricular ejection fraction (LVEF), and early mortality. Additionally, rats treated with recombinant sFlt-1 showed a 15 % reduction in LVEF and a 29 % reduction in cardiac output compared with control rats. High sFlt-1 concentrations were associated with a 15 % reduction in heart capillary density (number of vessels/cardiomyocyte) and a 24 % reduction in myocardial blood volume. Electron microscopy and histological analysis revealed mitochondrial damage and interstitial fibrosis in the hearts of sFlt-1-treated, but not control rats. In 5/6-nephrectomised rats, an animal model of CKD, sFlt-1 antagonism with recombinant VEGF121 preserved heart microvasculature and significantly improved heart function. Overall, these findings suggest that a component of cardiovascular risk in CKD patients could be directly attributed to sFlt-1. Assessment of patients with CKD confirmed that sFlt-1 concentrations were inversely correlated with renal function, while studies in rats suggested that sFlt-1 may link microvascular disease with HF in CKD.

[Cutaneous manifestations in hemodialysis patients]

BACKGROUND

Hemodialysis patients have frequent and various cutaneous manifestations of often hypothetical pathogenesis. Chronic renal failure (CRF) presents with an array of cutaneous manifestations. The objective was to evaluate the prevalence and nature of cutaneous lesions associated with CRF patients on hemodialysis patients.

PATIENTS AND METHODS

Transversal and observational study of 53 patients with CRF on regular hemodialysis.

RESULTS

There were 28 women and 25 men. Their mean age was 44 year-old. All patients had cutaneous manifestations and 64% complained of dermatological signs. Cutaneous xerosis and pigmentation disorders were found in 96 and 94% of patients, respectively. Other manifestations were pallor (41%), pruritus (20.7%), a diffuse hair loss (35.8%) and nails changes (66%).

COMMENTS

Cutaneous manifestations in hemodialysis patients are frequent polymorphous. Their incidence varies from 50 to 100% of the series. Their knowledge deserves a proper management by both dermatologists and nephrologists to improve the life quality of hemodialysis patients.

Clinicoepidemiological study of skin manifestations in patients of chronic renal failure on hemodialysis

Background:

Chronic renal failure (CRF) is associated with a variety of cutaneous manifestations as a result of underlying etiology as well as the various treatment modalities.

Aim:

To evaluate the prevalence of various dermatoses in patients with CRF on hemodialysis and to study the effect of hemodialysis on the intensity of pruritus.

Materials and Methods:

A total of 35 patients of CRF on hemodialysis having at least one cutaneous manifestation were included in the study.

Results:

Twenty-four (68.71%) cases in our study belonged to the age group of 50-69 years, out of which 16 cases were in the sixth decade. Xerosis and pruritus occurred in 80% and 65.71% of cases, respectively. Other common findings included pallor (68.57%), dyspigmentation (34.29%), cutaneous infections (34.39%), acquired perforating dermatosis (17.4%), and nail changes (60%). Hemodialysis failed to improve pruritus in 17 (73.9%) of our patients. Twenty-six patients (74.28%) suffered from hypertension, 13 of them also were known cases of type II diabetes mellitus. Five patients suffered exclusively from type II diabetes mellitus.

Conclusions:

In our small study, xerosis was the commonest finding and pruritus, the commonest symptom. The intensity of pruritus was largely unaffected by hemodialysis.

Non-invasive evaluation of skin cytokines secretion: an innovative complementary method for monitoring skin disorders

In this review, a novel non-invasive approach based on skin surface wash sampling is described. Since the epidermis possesses a high metabolic activity, the secretion of various biomarkers can be exploited to develop non-invasive procedures for skin measurement to monitor disorders and to define a therapeutic strategy. Thus, we developed a method for the quantification of skin surface compounds. In this procedure, a well is placed on skin surface and is attached using an adhesive pad. Extraction buffer is introduced into the well for 30 min incubation period and the secretion of different biomarkers on skin surface can be measured: cytokines, antioxidants, peptides, RNA, DNA volatile organic compounds etc. Here, the focus is on cytokine measurement. After collecting skin samples cytokines can be quantified using ELISA assay. Since so far cytokine levels in skin have been evaluated mostly by invasive and prolonged procedures (punch biopsy, blister fluid and scrapping), employing this method has important implications, because it allows assessing cytokine amount with minimal invasion and high accuracy. We have already applied skin surface wash sampling for cytokine quantification in different clinical conditions: psoriasis, atopic dermatitis and chronic renal failure. A distinct pattern of cytokine secretion has been demonstrated for each disorder. Differences were also observed between lesional and non-lesional areas. The obtained results shed a new light on cutaneous cytokine expression in different clinical conditions. Moreover, the interplay between cytokines and other soluble compounds can give an added value in understanding the mechanism of skin pathologies.

A prospective study of cutaneous abnormalities in patients with chronic kidney disease

There are diverse ways in which the skin is affected by chronic kidney disease (CKD). Various specific and nonspecific skin abnormalities are observed in patients with CKD. The aim of the study was to document the prevalence of skin diseases that commonly occur in patients with CKD on medical treatment and dialysis. A total of 99 patients with CKD were examined for evidence of skin diseases. Ninety-six had at least one cutaneous abnormality attributable to CKD. The most prevalent finding was xerosis (66.7%), followed by pallor (45.45%), pruritus (43.4%), and cutaneous pigmentation (32.3%). Other cutaneous manifestations included dermatitis (27.27%); Kyrle's disease (17.17%); fungal (8.08%), bacterial (11.1%), and viral (5.05%) infections; purpura (10.1%); gynecomastia (4.04%); and yellow skin (5.05%). The common nail changes were half and half nails (36.36%) and onycholysis (13.13%). CKD is associated with various cutaneous abnormalities caused either by the disease or by treatment, the most common being xerosis and pruritus. The dermatologic complications can significantly impair the quality of life in certain individuals; therefore, earlier diagnosis and treatment is important to improve their quality of life.

Sericin cream reduces pruritus in hemodialysis patients: a randomized, double-blind, placebo-controlled experimental study

Background

Uremic pruritus (UP) is a significant complication in ESRD patients and substantially impairs their quality of life. UP is considered to be a skin manifestation of chronic inflammation. Because sericin can suppress the release of pro-inflammatory cytokines, the purpose of this study was to investigate the short-term safety and efficacy of sericin cream for treating UP in hemodialysis patients.

Methods

This study used a double-blind design to investigate the effects of random topical administration of sericin cream and cream base (placebo) on either the right or left extremities of hemodialysis patients for 6 weeks. Skin hydration, irritation and pigmentation were evaluated every 2 weeks using Skin Diagnostic SD27. The visual analog scale for itching was also evaluated every 2 weeks, and the Kidney Disease Quality of Life Short Form was performed on the day of each patient’s enrollment and after 6 weeks of treatment.

Results

Fifty dialysis patients were enrolled, 47 of which completed the study. The hydration of the skin of the patients’ extremities increased significantly after administration of sericin cream; significant differences were found between sericin treatment and control after 6 weeks of treatment (p = 0.041 for arms and p = 0.022 for legs, respectively). Moreover, a significant difference was also found in skin irritation between the two treatments (p = 0.013 for arms and p = 0.027 for legs, respectively). At the end of the study, the skin pigmentation level was significantly reduced on both the arms (p = 0.032) and legs (p = 0.021) of the sericin-treated side compared with the side treated with cream base. The mean itching score decreased significantly from moderate to severe at the time of enrollment to mild pruritus after 6 weeks of treatment (p = 0.002). A better quality of life was found in all domains tested although statistically significant differences before and after treatment was found only in the patients’ pain scores, the effect of kidney disease on daily life, sleep quality and symptoms or problems related to kidney disease.

Conclusions

We conclude that sericin cream has a high potential for reducing UP in hemodialysis patients.

The trial registration number of this study is ISRCTN16019033; its public title is “sericin cream reduces pruritus in hemodialysis patients”.

Cutaneous manifestations in patients with chronic kidney disease on maintenance hemodialysis

Cutaneous disorders can precede or follow the initiation of hemodialysis treatment. We evaluated the prevalence of various dermatological manifestations in patients undergoing hemodialysis at least twice a week for minimum of three months at our center. Patients were excluded if they were undergoing hemodialysis less than twice a week or on hemodialysis secondary to ESRD following graft dysfunction. One hundred and forty-three patients were evaluated. Among them, there were 113 male and 30 females. Among the skin changes, pruritus accounted for 56%, Xerosis was observed in 52%, Diffuse blackish hyper pigmentation was seen in 40%. Skin infections was seen in 53% of patients, of these fungal, bacterial and viral infections were 27.2%, 14.6%, and 11.2%, respectively. Kyrle's disease was observed only in 6.9%. Other skin manifestations include eczema 4.8%, psoriasis 2.7%, and drug rash 2.1%. Nail changes were observed in 46 patients of whom 27 patients had onychomycosis. Other changes include discoloration, onycholysis, and splinter hemorrhages. Hair changes were observed in 21.7%. Mucosal changes were seen in 27.3%. In our study, pruritus, xerosis, and pigmentation were higher among skin changes. Recognition and management of some of these dermatological manifestations vastly reduce the morbidity and improve the quality of life.

Nail disorders in patients with chronic renal failure undergoing hemodialysis

BACKGROUND

Chronic renal failure affects almost all the systems of the body, including the skin and appendages. The nail disorders most commonly found in patients with chronic renal failure are half and half nails, absent lunula and splinter hemorrhages.

OBJECTIVES

To evaluate the spectrum and the frequency of nail disorders in patients with chronic renal failure submitted to hemodialysis and compare them with a paired sample from the general population.

METHODS

A case-controlled study paired for gender and age was conducted in which nail disorders were investigated in the two groups.

RESULTS

At least one nail disorder was found in 86% of the hemodialysis patients and in 75% of subjects in the control group. Absent lunula (62.9%) and half and half nails (14.4%) were more common in the hemodialysis group compared to the control group and this difference was statistically significant (p < 0.05). Longitudinal striae were more common in the control group compared to the hemodialysis group (24.1%).

CONCLUSIONS

Absent lunula and half and half nails were the most common nail disorders found in patients on hemodialysis, corroborating the findings of previous studies. Longitudinal striae were more common in the control group and future studies may clarify whether structural abnormalities such as absent lunula may be related to this finding.

[Pruritus and dryness of the skin in chronic kidney insufficiency and dialysis patients - a review]

The uremic pruritus is a very painful symptom suffered by chronic haemodialysis patients and is observed in 22 to 74% of the subjects. The causes of uremic pruritus have not yet been clarified. During the last 20 to 30 years it has been focused on altogether 5 different pathophysiological hypotheses: stimulating influences (e.g. calcium phosphate deposits in the epidermis), stimuli (e.g. secondary hyperparathyroidism), neuropathic injuries (e.g. disturbance of the cutaneous innervation in patients with uremic peripheral neuropathy), and central nervous changes (e.g. accumulation of endorphins in uremic patients which is associated with increasing pruritus), and immunologic conditions. The last mentioned immunological hypothesis has increasing importance, not at least based on the fact that the application of a topical calcineurin inhibitor (tacrolimus) improves the uremic pruritus. However, this fact could not be confirmed in a recent prospective placebo-controlled study from the USA. Only after kidney transplantation with a functioning transplant the uremic pruritus is stopped. That is why no causal therapy exists so far. Actually, the uremic pruritus has to be treated by topical and systemic means in a symptomatic and polypragmatic way only. Urea represents one of the most important "natural moisturizing factors" which are responsible for the hydration of the skin. It has been demonstrated that older patients have decreased urea levels within the stratum corneum of the epidermis, whereas in patients with terminal kidney insufficiency - despite dryness of the skin - as a paradox finding elevated levels of urea have been assessed in the stratum corneum. Because of this reason, the meaning of urea as part of the "natural moisturizing factors" system is not understood, until now. However, there are very promising results of clinical phase II studies showing a significant effect of topical application of 2.5% L-arginine hydrochlorid ointment - a semi-essential amino acid - on improvement of dryness and, in particular, on improvement of pruritus in haemodialysis patients.

Cutaneous manifestations of chronic kidney disease

Among the most common systemic diseases associated with cutaneous manifestations is kidney failure. Most of these occur in the setting of chronic kidney disease. In the following review, we will target 6 of these conditions in details. The entities are as follows: pruritus acquired perforating dermatoses, nail disorders, bullous disorders, calciphylaxis, and nephrogenic fibrosing dermopathy.

Pattern of skin and nail changes in chronic renal failure in Nepal: a hospital-based study

Chronic renal failure, regardless of its cause, often produces specific dermatological abnormalities, which can develop long before failure manifests clinically. Our aim was to study the clinical pattern of skin and nail changes in chronic renal failure and also study the associations of these changes with age, sex, etiology and duration of the chronic renal failure. A total of 104 diagnosed cases of chronic renal failure were included in the study over a period of 1 year. Equal numbers of age- and sex-matched individuals were taken as controls. The male : female ratio was 1.4:1. The mean duration of chronic renal failure was 19 +/- 20 months. Among cases and controls, 72% and 16% had skin changes, respectively. Xerosis was the most common of the skin changes (28%), followed by hyperpigmentation (20%), pruritus (15%), infectious diseases (5%) and other skin changes (33%) in chronic renal failure patients. Abnormal nail changes were seen in 82% of the cases compared to only 8% of the controls. In the cases, white nail was most common followed by brown and half-and-half nail. Pruritus was significantly higher in the dialysis group whereas the nail changes were significantly higher in the non-dialysis group. The skin and nail changes were common in chronic renal failure and manifested in various forms. Thus, thorough inspection of the integument might reveal markers of occult renal disease.

The prevalance, epidemiology and risk factors for onychomycosis in hemodialysis patients

BACKGROUND

Onychomycosis has a high prevalance among immunocompromised patients such as diabetics and hemodialysis patients. In the present study, we aimed to investigate the prevalence of onychomycosis among hemodialysis patients with and without diabetes mellitus, and to find out the factors likely to be associated with the development of onychomycosis among hemodialysis patients.

METHODS

One hundred and nine hemodialysis patients were enrolled. Fifty-seven of hemodialysis patients had the diagnosis of diabetes mellitus. Nail scrapings were obtained from 76 patients who had dystrophic nail changes. Samples were examined with 20% potassium hydroxide solution and all of the samples were inoculated on Saboraud's dextrose agar, potateus dextrose agar and mycobiotic agar. Diagnosis of onychomycosis was based on the presence of both positive clinical signs and positive potassium hydroxide test.

RESULTS

Onychomycosis was diagnosed in 26.6% of hemodialysis patients. Diabetes mellitus was present in 68.9% of patients with onychomycosis. Toenail scraping cultures were reported to be positive in 19.7% of patients with dystrophic nail changes. Logistic regression analysis revealed that the presence of diabetes mellitus and the mean duration of hemodialysis were the significant predictors associated with the development of onychomycosis.

CONCLUSION

The prevalence of dystrophic nail changes and onychomycosis is increased among hemodialysis patients. The dialysis duration and the presence of diabetes mellitus are the independent risk factors associated with the development of onychomycosis in uraemic patients.

Nail disorders in patients with chronic renal failure and undergoing haemodialysis treatment: a case-control study

BACKGROUND

Few controlled studies have compared nail disorders in patients with chronic renal failure (CRF) and haemodialysis (HD)-dependent individuals with a healthy population.

OBJECTIVE

The aim of this study was to compare the prevalence of nail disorders in patients with CRF and patients undergoing HD treatment with a healthy population, and evaluate the relationship between nail changes and various demographic, medical and laboratory parameters in these groups.

METHODS

In this case-control study we recruited 73 patients affected with CRF, 77 patients undergoing regular HD and 77 healthy individuals. All patients were examined for the presence of nail disorders. Various parameters [age, gender, type of kidney disease, regular medications, duration of renal failure and HD, dialysis efficacy (Kt/v), haemoglobin, neutrophil count, calcium, phosphorus, albumin, creatinine, urea, alkaline phosphatase and parathyroid hormone (PTH) levels] of the patients were determined by multivariate analysis and compared.

RESULTS

Forty-four patients (60.3%) with CRF and 48 patients (62.3%) undergoing HD treatment had at least one type of nail pathology. The most common nail alterations found in patients with CRF and those undergoing HD were absence of lunula (AL) and half-and-half nails (HHN), respectively. Prevalence of nail disorders among patients with CRF was influenced significantly by PTH level (P = 0.03). In the HD group, male sex, age above 65 years and comorbidities (diabetes mellitus, hypertension and heart failure) were significantly associated with nail pathologies.

CONCLUSION

Patients with CRF and those undergoing HD therapy have higher rates of nail disorders when compared to a healthy population. Efficient HD does not improve nail changes.

An update on pruritus associated with CKD

The prevalence of chronic kidney disease (CKD) and end-stage renal disease is increasing worldwide. Despite improvements in dialysis methods, including the development of novel biocompatible membranes and ultrapure dialysate, CKD-associated pruritus remains a common and significant public health issue. Not only does this distressing symptom profoundly impact on quality of life and sleep, recent evidence showed that pruritus also was associated with poor patient outcome. Nonetheless, nephrologists and other health care professionals often fail to recognize and adequately address the pruritus associated with CKD. The pathophysiological mechanism of CKD-associated pruritus is poorly defined, and, as a result, the development of specific therapies has proved to be a challenge. The purpose of this review is to highlight the importance of this neglected topic by providing an overview of recent epidemiological studies, outcomes data, proposed pathophysiological mechanisms, and emerging treatment options.

Unusual palmoplantar blistering in the setting of hemodialysis: a case report and review of the dermatoses associated with hemodialysis

We describe a 70-year-old White female on maintenance high-flux hemodialysis for chronic renal insufficiency with an abrupt onset of asymptomatic palmoplantar blisters. The lesions were tense, noninflamed and 0.2-1.0 cm in dimension. Concomitant photo-distributed blistering of the dorsal hands and forearms was not present. A cutaneous biopsy demonstrated nonspecific histological and direct immunofluorescent findings. Serum indirect immunofluorescence and tissue cultures for bacteria, fungi and viruses were negative. Fecal porphyrins were normal but an elevated plasma uroporphyrin level of 17.0 microg/dL (normal: < 1.0 microg/dL) was observed. The duration of each hemodialysis treatment, which the patient had continued to receive three times per week, was changed from 2 to 2.5 h. Within 2 weeks no new blisters occurred. Within 6 weeks complete clinical and biochemical remission was noted. During this time course no topical steroid or antifungal therapy was employed nor was the patient's oral medication regimen altered.

An epidemiology study of patients with uremic pruritus

BACKGROUND

Pruritus is a common problem in continuous ambulatory peritoneal dialysis (CAPD) and haemodialysis patients. There are few studies on the clinical characteristics of uremic itch, the cause of which is still unknown.

OBJECTIVES

The aim of this study was to define the prevalence and clinical characteristics of pruritus in CAPD and haemodialysis patients.

METHODS

A questionnaire was used to evaluate pruritus in 52 CAPD and 289 haemodialysis patients in two dialysis units. The relationship of various factors and medical parameters to itch was examined.

RESULTS

Of the 341 patients, 177 (51.9%) had pruritus at the time of examination, 97 (28.4%) had pruritus in the past. Pruritus was present in 145 (50.2%) of the haemodialysis patients and 32 (61.5%) of the CAPD patients. Men, patients with liver disease, and patients with pruritus before starting dialysis treatment were more likely to have uremic pruritus.

CONCLUSIONS

This study showed us that uremic pruritus was observed more in men than women. The high prevalence of uremic pruritus in our study does not support the decrease of pruritus due to an improvement in the management of dialysis patients.

Etiology and prognostic significance of severe uremic pruritus in chronic hemodialysis patients

Although uremia is well known as the most common cause of pruritus, the mechanisms of pruritus in chronic hemodialysis patients remain unclear. The purpose was to characterize uremic pruritus in more detail and to investigate whether severe pruritus is a marker for poor prognosis. A total of 1773 adult hemodialysis patients were studied. A questionnaire was given to each patient to assess the intensity and frequency, as well as pruritus-related sleep disturbance. We analyzed the relationship between clinical and laboratory data and the severity of pruritus in hemodialysis patients and followed them for 24 months prospectively. In total, 453 patients had severe pruritus with a visual analogue scale (VAS) score more than or equal to 7.0. Among them, more than 70% complained of sleep disturbance, whereas the majority of patients with a VAS score of less than 7.0 had no sleep disturbance. Male gender, high levels of blood urea nitrogen, beta2-microglobulin (beta2MG), hypercalcemia, and hyperphosphatemia were identified as independent risk factors for the development of severe pruritus, whereas a low level of calcium and intact-parathyroid hormone were associated with reduced risk. During the follow-up, 171 (9.64%) patients died. The prognosis of patients with severe pruritus was significantly worse than the others. Moreover, severe pruritus was independently associated with death even after adjusting for other clinical factors including diabetes mellitus, age, beta2MG, and albumin. Severe uremic pruritus caused by multiple factors, not only affects the quality of life but may also be associated with poor outcome in chronic hemodialysis patients.