Uraemic pruritus: clinical characteristics, pathophysiology and treatment

Pathways for Diagnosing and Treating CKD-Associated Pruritus: A Narrative Review

Purpose of Review

Chronic kidney disease (CKD)-associated pruritus is a common, persistent, and distressing itch experienced by patients across the CKD spectrum. Although the disorder is associated with adverse outcomes and poor health-related quality of life, it remains underdiagnosed and undertreated. The purpose of this narrative review is to offer health care providers guidance on how to effectively identify, assess, and treat patients with CKD-associated pruritus, with the goal of reducing symptom burden and improving patient-important outcomes, such as quality of life (QoL).

Sources of Information

A panel of nephrologists and researchers from across Canada and the United States was assembled to develop this narrative review based on the best available data, current treatment guidelines, and their clinical experiences.

Methods

A panel of nephrologists who actively care for patients with pruritus receiving dialysis from across Canada was assembled. Two researchers from the United States were also included based on their expertise in the diagnosis and management of CKD-associated pruritus. Throughout Spring 2023, the panel met to discuss key topics in the identification, assessment, and management of CKD-associated pruritus. Panel members subsequently developed summaries of the pertinent information based on the best available data, current treatment guidelines, and added information on their own clinical experiences. In all cases, approval of the article was sought and achieved through discussion.

Key Findings

This narrative review provides pragmatic guidance addressing: (1) methods for screening CKD-associated pruritus, (2) assessing severity, (3) management of CKD-associated pruritus, and (4) suggested areas for future research. The panel developed a 3-pillar framework for proactive assessment and severity scoring in CKD-aP: systematic screening for CKD-associated pruritus (pillar 1), assessment of pruritus intensity (pillar 2), and understanding the impact of CKD-associated pruritus on the patient's QoL (pillar 3). Management of CKD-associated pruritus can include ensuring optimization of dialysis adequacy, achieving mineral metabolism targets (ie, calcium, phosphate, and parathyroid hormone). However, treatment of CKD-associated pruritus usually requires additional interventions. Patients, regardless of CKD-associated pruritus severity, should be counseled on adequate skin hydration and other non-pharmacological strategies to reduce pruritus. Antihistamines should be avoided in favor of evidence-based treatments, such as difelikefalin and gabapentin.

Limitations

A formal systematic review (SR) of the literature was not undertaken, although published SRs were reviewed. The possibility for bias based on the experts' own clinical experiences may have occurred. Key takeaways are based on the current available evidence, of which head-to-head clinical trials are lacking.

Funding

This work was funded by an arm's length grant from Otsuka Canada Pharmaceutical Inc. (the importer and distributer of difelikefalin in Canada). LiV Medical Education Agency Inc. provided logistical and editorial support.

Chronic Kidney Disease-Associated Pruritus and Quality of Life: Learning from Our Patients

Chronic kidney disease-associated pruritus is itching directly related to kidney disease that cannot be explained by any other condition. Despite technological advances in the different aspects of dialysis sessions and the best treatment for chronic kidney disease patients, it is still a common problem in our patients. The many complex physiological mechanisms involved, the different hypotheses made over the years on the aetiology of the condition, and the great clinical variability may partially explain the limited knowledge about this problem and the difficulties in treating it. The presence of all these factors leads to the persistence of unpleasant symptoms, which must affect the disease burden and quality of life of kidney patients. Through the presentation of an illustrative clinical case, the aim of this review article is to highlight the need for adequate diagnosis and an improved approach to all aspects of chronic kidney disease-associated pruritus, in view of the heavy burden of the disease and the huge impact on the patient's quality of life.

Higher Symptom Frequency and Severity After the Long Interdialytic Interval in Patients on Maintenance Intermittent Hemodialysis

Introduction

Patients on intermittent hemodialysis (HD) have a high symptom burden. Though studies report higher hospitalizations and mortality after the long interdialytic interval, whether symptoms vary based on the interdialytic interval is unclear.

Methods

This is a prospective observational study of patients over the age of 18 who received in-center HD. Patients were surveyed on the presence and severity of 20 different symptoms at the end of 12 HD sessions. Wilcoxon signed-rank test was used for comparison of severity for each symptom by the interval. Multivariable generalized estimating equation with Poisson regression by repeated measure method was used to determine the association of interdialytic interval and symptom frequency while adjusting for potential confounders.

Results

From the 97 patients enrolled, the most common symptoms were fatigue (60.8%), cramping (58.8%), and dry skin (52.6%). There was large variability in the frequency of symptoms, ranging 0% to 8% of treatments. The most severe symptoms were bone pain (mean severity score 2.2±0.9) and diarrhea (mean severity score 2.2±0.7). Eight of the 20 symptoms were significantly more common after the long interdialytic interval including fatigue (22% vs. 15%, P < 0.001) and cramping (21% vs. 16%, P = 0.003). The long interval had a 37% higher incidence rate for symptoms compared to the short interval even after adjustment. Results were similar across genders.

Conclusion

Symptoms are more common after the long interdialytic interval. Clinical assessment and research evaluating patient symptoms need to be cognizant of when patients are surveyed or include the length of interdialytic interval as a confounding variable.

Unravelling the pathophysiology of chronic kidney disease-associated pruritus

For decades, itch related to chronic kidney disease (CKDaP) has been a clinical problem, but the aetiology and pathophysiology of CKDaP are still not yet fully understood—currently the underlying pathophysiological mechanisms are thought to be multifactorial. As new therapeutic targets have recently been identified and clinical trials have shown promising results, our current understanding of the interrelationships has expanded significantly. Here we review the pathophysiology and recent findings on modulation and sensitization of itch contributing to the development of CKDaP, covering hypothesis regarding immune system dysfunction, metabolic changes, uremic toxin deposition, peripheral neuropathy and imbalances in the endogenous opioid system.

Do you feel itchy? A guide towards diagnosis and measurement of chronic kidney disease-associated pruritus in dialysis patients

Chronic kidney disease-associated pruritus (CKD-aP) is a potentially distressing condition that affects a significant proportion of patients with end-stage kidney disease undergoing dialysis. CKD-aP may lead to worsening of patients' physical and mental health-related quality of life (HRQoL) and has also been linked with worse clinical outcomes, including increased mortality. Despite these detrimental effects, evidence from real-world studies shows that CKD-aP still remains overlooked by nephrologists and underreported by patients in clinical practice. Itch is subjective and therefore its diagnosis is often dependent on patients reporting this symptom. There is an opportunity to reduce the burden of CKD-aP on dialysis patients by increasing awareness about this condition and the availability of effective treatments. It is particularly important that nephrologists and other healthcare providers routinely ask their patients if they are experiencing itch. The differential diagnosis of CKD-aP requires a step-by-step identification and exclusion of possible alternative or concomitant causes of itch. Several simple validated self-reported assessment scales are available to evaluate the presence and severity of itch in a time-efficient manner, making them suitable for use in everyday clinical practice. The impact of CKD-aP on haemodialysis patients' HRQoL should also be assessed on a regular basis. This review provides a comprehensive overview of the differential diagnosis of CKD-aP and the diagnostic tools that are available to identify itch and quantify its severity and impact on patient HRQoL. A suggested algorithm to guide the screening, diagnosis and assessment of CKD-aP among dialysis patients in real-world practice is provided.

Chronic Intractable Pruritus in Chronic Kidney Disease Patients: Prevalence, Impact, and Management Challenges - A Narrative Review

Chronic kidney disease (CKD) is recognized as a leading public health problem and causes numerous health complications. One of the most common and burdensome dermatological symptoms affecting patients undergoing dialysis is CKD-associated pruritus (CKD-aP). This condition not only has a negative impact on sleep, mood, daily activities, and quality of life but also increases the mortality risk of hemodialyzed patients. Despite that, this condition is greatly underestimated in clinical practice. Due to the complex and still not fully understood etiopathogenesis of CKD-aP, the choice of an effective therapy remains a challenge for clinicians. Most common therapeutic algorithms use topical treatment, phototherapy, and various systemic approaches. This review aimed to summarize most recent theories about the pathogenesis, clinical features, and treatment of CKD-aP.

A Narrative Review of Management Strategies for Common Symptoms in Advanced CKD

Patients with advanced chronic kidney disease (CKD) experience multiple bothersome symptoms, undermining their quality of life (QOL). With growing attention to the importance of symptom management in advanced CKD, the evidence regarding symptoms is increasing. In this review, we briefly summarize the current evidence of effective pharmacologic and nonpharmacologic interventions to improve symptoms and QOL in patients with advanced CKD, including those on dialysis. We focused on symptoms that are commonly experienced by patients, such as pain, fatigue, sleep disturbances, itching, nausea and vomiting, cognitive impairment, and anxiety and depression. We noted that research in symptom science focused on improving symptom management in CKD is still very limited. In addition to the lack of clinical practice guidelines to address those common symptoms, the major gaps in the current literature include the evidence regarding mechanistic pathways to inform the development of effective symptom management for CKD populations, the evidence to confirm effective pharmacologic interventions in other populations for CKD populations, and research on how to incorporate effective symptom management approaches into clinical care. Although improving mortality remains as an important area in the kidney community, there is an urgent need to focus on improving symptom management to improve QOL in advanced CKD.

Efficacy of uremic pruritus treatment in patients undergoing hemodialysis, a network meta-analysis for randomized clinical trials

INTRODUCTION

Uremic pruritus is very common in hemodialysis or renal failure patients, there were lots of available treatments such as gabapentin, pregabalin, ondansetron, etc. However, there is no quantified study comparing these treatments together, it is impossible to conduct a clinical trial involving so many treatments, so we conduct a network meta-analysis to compare them.

METHOD

We collected mean difference and standard error of visual analogue scale data as outcome. In total we collected 15 articles, 15 articles, 1180 subjects and 6 treatments included to this study.

RESULTS

In these comparisons, gabapentin showed the largest effect MD: 5.19, 95%CI [3.77, 6.61], anti-histamine MD: 4.65, 95%CI [2.22, 7.07] and pregabalin MD: 4.62, 95%CI [2.71, 6.62] showed a similar effect. Opioid pathway related treatment also showed a significant but not so large effect MD: 2.45, 95%CI [0.41, 4.49]. Ondansetron and Doxepin didn't show a significant improvement among placebo, the overall quantifying heterogeneity I²=43.1%. There is no statically difference between gabapentin, pregabalin and anti-histamine treatments.

CONCLUSIONS

So we conclude that gabapentin, pregabalin and anti-histamine has a similar efficacy on pruritus control.

Complementary and alternative medicine therapies for uremic pruritus - A systematic review of randomized controlled trials

INTRODUCTION

Uremic pruritus (UP) is one of the most bothersome symptoms among chronic kidney disease (CKD) patients. The pathophysiology of UP remains elusive, resulting in limited treatment options. The inability of standard medical treatments to provide effective relief has piqued interest in complementary and alternative medicine (CAM).

METHODOLOGY

A systematic review of randomized controlled trials (RCTs) summarizing the efficacy and safety profile of CAM used for UP in CKD patients was performed. CAM interventions were classified using categories proposed by the National Center for Complementary and Integrative Health. The efficacy of each CAM was determined from changes in UP severity and all reported adverse effects were extracted.

RESULTS

Of 5242 articles screened, 34 RCTs were included, with 15 (44.1 %) studies having a sample size greater than 50. The studies considered 21 treatments including omega-3 fatty acid supplementation (n=5), acupuncture (n=5), topical capsaicin (n=4) and acupressure (n=3). Acupuncture, acupressure and topical capsaicin were shown to be effective in improving uremic pruritus. Interventions which include oral omega-3 fatty acid and zinc supplementation demonstrated mixed efficacy. Other therapies such as evening primrose oil, turmeric, vitamin B3, vitamin D and thermal therapy were not effective for treatment of UP. Common adverse effects reported with topical capsaicin included mild burning sensations (50.0-88.2 %) or erythema (6.7-22.7%) while that of acupuncture included soreness (7.5 %), bleeding (6.0-7.5%) and hematoma (1.9 %).

CONCLUSIONS

Acupuncture, acupressure and topical capsaicin have the largest body of evidence for efficacy in the treatment of UP. Larger and higher quality RCTs are required to examine the efficacy and safety of promising CAM.

Recent advances in understanding the molecular mechanisms of cholestatic pruritus: A review

Cholestasis, a condition characterized by an abnormal decrease in bile flow, is accompanied by various symptoms such as pruritus. Although cholestatic pruritus is a prominent condition, its precise mechanisms have largely been elusive. Recently, advancements have been made for understanding the etiology and pathogenesis of cholestatic pruritus. The current review therefore focuses on summarizing the overall progress made in the elucidation of its molecular mechanisms. We have reviewed the available animal models on cholestasis to compare the differences between them, characterized potential pruritogens involved in cholestatic pruritus, and have summarized the receptor and ion channels implicated in the condition. Finally, we have discussed the available treatment options for alleviation of cholestatic pruritus. As our understanding of the mechanisms of cholestatic pruritus deepens, novel strategies to cure this condition are awaited.

Evaluation of Efficacy of Mirtazapine on Pruritus and Serum Histamine and Serotonin Levels in Patients Undergoing Hemodialysis: A Before-After Pilot Clinical Trial

Background

Although chronic kidney disease-associated pruritus (CKD-aP) remains a frequent and frustrating symptom in patients with advanced kidney diseases, its optimal treatments are not well defined. Based on its mechanism of action, as a histamine-1 (H1), 5-(hydroxytryptamine) HT2, and 5HT3-receptor blocker, mirtazapine may be effective in the treatment of CKD-aP. Hence, this study aimed to investigate the efficacy of mirtazapine for the treatment of pruritus in patients undergoing hemodialysis (HD).

Methods

A before-after clinical trial was conducted from September 2018 until March 2019, on 30 HD-patients that had been referred to the HD ward of a tertiary hospital, in Hamadan, Iran. After the 2-week washout period, mirtazapine was administered with a dosage of 15 mg/day for an additional 2 weeks. At baseline and at each dialysis session, the effects of the mirtazapine on the pruritus severity based on the visual analogue scale (VAS) and degree of sleep interference resulting from the pruritus were asked and recorded. Additionally, at the baseline and the end of 2 weeks of treatment, the serum histamine and serotonin levels, as the main chemical pruritogens evoking pruritus symptoms, were also determined.

Results

Twenty-seven patients completed the entire course of the study. Based on the general linear model analysis, a progressive decline in the mean VAS score was observed over time during the study. The mean VAS score decreased from 8.48 ± 1.01 at baseline to 1.04 ±0.79 at the end of treatment (P-value<0.001). Similarly, the mean sleep interference scores were also significantly improved throughout treatment (decreased from 8.07±1.43 to 2.81± 0.74; P-value<0.001). Further, at the end of the treatment, a noticeable decrement in the serum histamine level was also seen (P-value = 0.006). The drug was acceptably well-tolerated and a majority of the patients were satisfied with this treatment.

Conclusion

This pilot study suggests that mirtazapine may be an effective treatment option for the management of CKD-aP. However, further studies would be needed to confirm these results.

Development and Validation of a Uremic Pruritus Treatment Algorithm and Patient Information Toolkit in Patients With Chronic Kidney Disease and End Stage Kidney Disease

CONTEXT

Uremic pruritus (UP) affects up to half of all patients with kidney disease and has been independently associated with poor patient outcomes. UP is a challenging symptom for clinicians to manage as there are no validated guidelines for its treatment.

OBJECTIVES

The study aimed to develop and validate an algorithm and patient information toolkit for the treatment of UP in patients with kidney disease.

METHODS

The study involved a literature search and development of an initial draft algorithm, followed by content and face validation of this algorithm. Validation entailed three rounds of interviews with six nephrology clinicians per round. Participants assessed the relevance of each component of the algorithm and then rated a series of statements on a scale of 1-5 to assess face validity of the algorithm. After each round, the content validity index (CVI) of each algorithm component was calculated, and the algorithm was revised by the study team in response to findings. This process was followed by a second study that developed and validated a patient information pamphlet and video.

RESULTS

Algorithm validation participants were affiliated with three institutions and included seven physicians, four registered nurses, three nurse practitioners, three pharmacists, and a dietician. The average CVI of the algorithm components across all three rounds was 0.89, with 0.80 commonly cited as the lower acceptable limit for content validation. More than 78% of participants rated each face validity statement as "Agree" or "Strongly Agree". For the patient information tools, five clinicians and 15 patients were included in validation. The average CVI was 1.00 for both tools, and the average face validity was 92%.

CONCLUSION

A treatment algorithm and patient information toolkit for managing UP in patients with kidney disease were developed and validated through expert review. Further research will be conducted on implementation of the treatment algorithm and evaluating patient-reported outcomes.

Uremic Pruritus: Prevalence and Impact on Quality of Life and Depressive Symptoms in Hemodialysis Patients

Background

End-stage renal disease (ESRD) is a major public health problem with many associated symptoms. Uremic pruritus (UP) develops in 40% of patients on hemodialysis and has major effects on the patient’s life. It is also an independent risk factor for increased mortality, and its psychiatric implications remain poorly characterized in our local setup, where it tends to be underdiagnosed and undertreated.

Objectives and rationale

The study aims to report the prevalence of uremic pruritus in our study population and associate it with various patient parameters, which may define a subset of patients at high risk for this pruritus. We also assess the effects of uremic pruritus on the patient’s quality of life (by using the Dermatology Life Quality Index; DLQI) and depressive symptoms (by using the Public Health Questionnaire; PHQ-9).

Materials and methods

It was a descriptive, cross-sectional study conducted in the nephrology unit of the multi-organ failure (MOF) center of the Holy Family Hospital (HFH), Rawalpindi, Pakistan, from February 2019 to June 2019, during which 173 male patients on hemodialysis were selected. Informed consent was taken from patients and other skin-related causes of pruritis were excluded. Uremic pruritus was defined as pruritis lasting for at least three months after the onset of ESRD. The 5-D, PHQ-9, and DLQI questionnaires were used to assess pruritis, depressive symptoms, and quality of life, respectively. Their Cronbach's Alpha values for 73 responses were 0.83, 0.81, and 0.71, respectively. The descriptive analysis was performed using SPSS v23.0 (IBM Corp, Armonk, NY, US). Spearman’s rank-order correlation, independent samples t-test, and one-way analysis of variance (ANOVA) were used to analyze study variables.

Results

The prevalence of uremic pruritus was 49.1%, with many patients having generalized itching. Unemployment and longer disease duration predisposed the patients towards uremic pruritus, as the mean 5-D score in this subset were greater (p<0.05 in the independent samples t-test). The results of one-way ANOVA were significant (p<0.05), indicating higher 5-D scores in worsening categories of depressive symptoms and quality of life. Spearman’s correlation matrix showed that 5-D, PHQ-9, and DLQI scores were strongly correlated with each other.

Conclusions

The prevalence of uremic pruritus among male hemodialysis patients is high, at 49.1%. It significantly contributes to depressive symptoms and a lower quality of life, which are associated with worse prognosis in hemodialysis patients. Thus, a clinician must keep in mind the psychiatric implications of uremic pruritus and treat it effectively to optimize the patient’s medical care.

Safety and efficacy of glecaprevir and pibrentasvir in Japanese hemodialysis patients with genotype 2 hepatitis C virus infection

BACKGROUND

Until recently, interferon-free anti-hepatitis C virus (HCV) therapy for genotype 2 (GT2) HCV-infected hemodialysis patients was an unfulfilled medical need. Recent clinical trials of glecaprevir and pibrentasvir (G/P) for hemodialysis patients showed high efficacy and safety; however, the number of GT2 HCV-infected patients, especially Asian patients, was limited and most of them were treated with a 12-week regimen. In this prospective multicenter study, we aimed to investigate the efficacy and safety of G/P in Japanese hemodialysis patients with GT2 HCV infection.

METHODS

Twenty-seven Japanese hemodialysis patients with GT2 HCV infection who were started on with 8- or 12-week G/P regimen between November 2017 and June 2018 were included and followed up for around 12 weeks after treatment completion.

RESULTS

Among the 27 included patients, 13 non-liver cirrhosis (LC) and direct-acting antivirals (DAAs)-naïve patients were treated with 8 weeks of G/P and 14 patients with LC (n = 13) or history of failure of DAAs (n = 1) were treated with a 12-week regimen. The overall sustained virological response at 12 weeks after treatment completion (SVR 12) was 96.3% (26/27). All patients with 8 weeks of treatment achieved SVR12. Two patients discontinued the therapy at 2 and 11 weeks after treatment initiation. The patient who discontinued at 2 weeks due to pruritus alone failed to respond to G/P. No patients experienced lethal adverse events during the therapy, and the most common adverse event was pruritus.

CONCLUSIONS

An 8- or 12-week G/P regimen is highly effective and safe in GT2 HCV-infected hemodialysis patients.

Water-Soluble Extract from Actinidia arguta (Siebold & Zucc.) Planch. ex Miq. and Perilla frutescens (L.) Britton, ACTPER, Ameliorates a Dry Skin-Induced Itch in a Mice Model and Promotes Filaggrin Expression by Activating the AhR Signaling in HaCaT Cells

With a complex etiology involving multiple factors, the condition known as itch is a primary symptom of many skin diseases. Current treatment methods are ineffective for addressing itches caused by dry skin, for example. We developed a botanical extract, ACTPER, made from a mixture of Actinidia arguta and Perilla frutescens, which have traditionally been used to treat itch. The quality of ACTPER as a research agent was controlled in our experiment by cell-based bioassays, as well as by high-performance liquid chromatography (HPLC), using two chemical markers. In the acetone-induced dry skin mice model, the oral administration of ACTPER alleviated dry skin-related skin properties and itching behavior. The RNA and protein expression of the filament aggregating protein (filaggrin) gene, a key factor involved in the regulation of skin barrier function, was significantly increased, as measured by quantitative reverse transcription polymerase chain reaction (RT-PCR) and immunofluorescence assay. To understand the underlying mechanism(s) at the molecular level, HaCaT cells, a human keratinocyte-derived cell line, were treated with various concentrations of ACTPER. We found that the protein expression of filaggrin was indeed upregulated by ACTPER in a dose dependent manner. Data from experiments involving the reporter plasmid containing the xenobiotic response element (XRE), and the chemical antagonist for the aryl hydrocarbon receptor (AhR), indicated that the ACTPER-mediated upregulation of filaggrin was controlled through the activation of the AhR signaling pathway. The molecular docking simulation study predicted that ACTPER might contain chemical compounds that bind directly to AhR. Taken together, our results suggest that ACTPER may provide the platform, based upon which a variety of safe and effective therapeutic agents can be developed to treat itch.

Chronic Renal Failure as a Possible Risk Factor for Allergic Reaction in Therapeutic Plasma Exchange Using Fresh Frozen Plasma

The incidence of allergic reactions in patients with chronic renal failure during plasma exchange using fresh frozen plasma is not well known. We retrospectively reviewed 62 patients who underwent plasma exchange between January 2013 and May 2018. The most common indication for plasma exchange was desensitization/preconditioning for kidney transplant (61.3%, 38/62). The incidence of allergic reactions was significantly higher in patients with chronic renal failure than patients without (57.1% vs. 25.0%, P = 0.029). Also, the incidence of allergic reactions tended to be higher in peritoneal dialysis patients (75%, 3/4) than in hemodialysis (58.8%, 10/17) and preemptive kidney transplant (58%, 11/19). These results suggested the relationship of chronic renal failure and the incidence of allergic reactions in patients undergoing therapeutic plasma exchange using fresh frozen plasma.

Current treatment strategies in refractory chronic pruritus

Chronic pruritus is a highly prevalent, debilitating disease, which is often refractory to conventional therapies. A step-wise, guideline-driven approach should be adopted in the management of these patients. Emollients as well as topical corticosteroids if appropriate should be initiated whilst looking for the cause underlying the pruritus. If these measures fail, and the origin of the pruritus remains unknown, cannot be treated or does not respond to therapy, systemic therapies as for example gabapentinoids, antidepressants, mu-opioid-receptor antagonists or, in case of inflammatory conditions, immunosuppressive drugs should be recommended. Novel agents, especially systemic monoclonal antibodies, neurokinin-1 receptor antagonists and opioid receptor modulators, are promising in providing relief in refractory cases.

Acupuncture Application in Chronic Kidney Disease and its Potential Mechanisms

Chronic kidney disease (CKD) is an increasing major public health problem worldwide. The number of CKD patients on hemodialysis is growing rapidly as well. Acupuncture technique is one of the traditional Chinese medicine methods and has been used in a variety of diseases. Nowadays, the clinical application of acupuncture technique for CKD patients has become the focus for its effectiveness and security. In this paper, we will review the therapeutic effects and mechanisms of different acupuncture techniques for CKD patients. In patients with CKD, acupuncture improves renal function, reduces proteinuria, controls hypertension, corrects anemia, relieves pain, and controls many hemodialysis-related complications such as uremic pruritus, insomnia and fatigue. The mechanisms are related to the regulation of sympathetic nerve and the activation of bioactive chemicals. In conclusion, acupuncture is proved to be beneficial for CKD patients. More research, however, is needed to verify the potential mechanisms.

Post-marketing surveillance study of the safety and efficacy of nalfurafine hydrochloride (Remitch® capsules 2.5 μg) in 3,762 hemodialysis patients with intractable pruritus

Background

Intractable pruritus in hemodialysis patients can significantly decrease their quality of life and is also associated with poor vital prognosis. Although combined multiple causes of intractable pruritus in these patients have been identified, no existing treatments are proven to be sufficiently effective. We conducted a post-marketing surveillance to follow-up and assess the safety and efficacy of nalfurafine, a selective κ-opioid receptor agonist, for the treatment of intractable pruritus in patients undergoing hemodialysis.

Patients and methods

Hemodialysis patients with intractable pruritus from institutions in Japan who received oral nalfurafine hydrochloride between January 2010 and December 2013 were enrolled in the surveillance. Surveillance was completed in July 2015. Safety data during 1 year after nalfurafine treatment onset, and efficacy data of nalfurafine evaluating the first 12-week treatment period and the following period until 1 year after the initial dose of nalfurafine (using global assessment of the itch improvement by the physician, Visual Analog Scale, and the Shiratori's severity scores) were collected and analyzed.

Results

In total, 3,762 patients were analyzed for safety. Adverse drug reactions were experienced by 402/3,762 (10.69%) patients. The most frequent adverse drug reactions were insomnia (127/3,762 [3.38%] patients), constipation (34 [0.90%]), somnolence (32 [0.85%]), dizziness (23 [0.61%]), nausea (13 [0.35%]), and malaise (9 [0.24%]). No patients developed dependence on nalfurafine. Nalfurafine was effective in 82.50% (2,880/3,491) of patients during the first 12 weeks and in 84.95% (2,167/2,551) on treatment during the subsequent period until 1 year after nalfurafine treatment initiation. Statistically significant decreases were reported in the Visual Analog Scale and the Shiratori's severity scores (p<0.001).

Conclusion

Oral nalfurafine hydrochloride (from 2.5 μg/day to a maximum of 5.0 μg/day) continues to be safe and effective for the treatment of intractable pruritus in hemodialysis patients in real-world clinical settings.

Treatment of Uremic Pruritus: A Systematic Review

BACKGROUND

Uremic pruritus is a common and burdensome symptom afflicting patients with advanced chronic kidney disease (CKD) and has been declared a priority for CKD research by patients. The optimal treatments for uremic pruritus are not well defined.

STUDY DESIGN

Systematic review.

SETTING & POPULATION

Adult patients with advanced CKD (stage ≥ 3) or receiving any form of dialysis.

SELECTION CRITERIA FOR STUDIES

PubMed, CINAHL, Embase, International Pharmaceutical Abstracts, Scopus, Cochrane Library, and ClinicalTrials.gov from their inception to March 6, 2017, were systematically searched for randomized controlled trials (RCTs) of uremic pruritus treatments in patients with advanced CKD (stage ≥ 3) or receiving any form of dialysis. 2 reviewers extracted data independently. Risk of bias was assessed using the Cochrane Collaboration risk-of-bias tool.

INTERVENTION

Any intervention for the treatment of uremic pruritus was included.

OUTCOMES

A quantitative change in pruritus intensity on a visual analogue, verbal rating, or numerical rating scale.

RESULTS

44 RCTs examining 39 different treatments were included in the review. These treatments included gabapentin, pregabalin, mast cell stabilizers, phototherapy, hemodialysis modifications, and multiple other systemic and topical treatments. The largest body of evidence was found for the effectiveness of gabapentin. Due to the limited number of trials for the other treatments included, we are unable to comment on their efficacy. Risk of bias in most studies was high.

LIMITATIONS

Heterogeneity in design, treatments, and outcome measures rendered comparisons difficult and precluded meta-analysis.

CONCLUSIONS

Despite the acknowledged importance of uremic pruritus to patients, with the exception of gabapentin, the current evidence for treatments is weak. Large, simple, rigorous, multiarm RCTs of promising therapies are urgently needed.

Targeting the Opioid Pathway for Uremic Pruritus: A Systematic Review and Meta-analysis

BACKGROUND

Patients undergoing hemodialysis or peritoneal dialysis often experience pruritus which is associated with morbidity and mortality. One proposed treatment approach is to target the opioid pathway using either µ-opioid antagonists or κ-opioid agonists.

OBJECTIVE

To review the efficacy of targeting the opioid pathway for pruritus among dialysis patients (uremic pruritus).

DESIGN

Systematic review and meta-analysis.

SETTING/METHODS

The systematic review included randomized controlled and randomized crossover trials identified in the MEDLINE, EMBASE, and Cochrane databases (1990 to June 2014) evaluating the efficacy of µ-opioid antagonists or κ-opioid agonists in the treatment of uremic pruritus.

PATIENTS

Adult (≥18 years) chronic dialysis patients.

MEASUREMENTS

The primary outcome being evaluated was reduction in itch severity measured on a patient-reported visual analog scale (VAS).

RESULTS

Five studies out of 3587 screened articles met the inclusion criteria. Three studies evaluated the efficacy of naltrexone, a µ-opioid antagonist, and 2 studies evaluated the efficacy of nalfurafine, a κ-opioid agonist. Duration of included studies was short, ranging from 2 to 9 weeks.

LIMITATIONS

Due to the heterogeneity in reporting of outcomes, data from the studies evaluating naltrexone could not be pooled. Pooled analysis, using a random effects model, found that use of nalfurafine resulted in a 9.50 mm (95% confidence interval [CI], 6.27-12.74, P < .001) greater reduction of itch severity (measured on a 100-mm VAS) than placebo in the treatment of uremic pruritus.

CONCLUSIONS

Nalfurafine holds some promise with respect to the treatment of uremic pruritus among dialysis patients. However, more long-term randomized controlled trials evaluating the efficacy of therapies targeting the opioid pathway for uremic pruritus are required.

Pharmacological interventions for pruritus in adult palliative care patients

BACKGROUND

This is an update of the original Cochrane review published in 2013 (Issue 6). Pruritus occurs in patients with disparate underlying diseases and is caused by different pathologic mechanisms. In palliative care patients, pruritus is not the most prevalent but is one of the most puzzling symptoms. It can cause considerable discomfort and affects patients' quality of life.

OBJECTIVES

To assess the effects of different pharmacological treatments for preventing or treating pruritus in adult palliative care patients.

SEARCH METHODS

For this update, we searched CENTRAL (the Cochrane Library), and MEDLINE (OVID) up to 9 June 2016 and Embase (OVID) up to 7 June 2016. In addition, we searched trial registries and checked the reference lists of all relevant studies, key textbooks, reviews and websites, and we contacted investigators and specialists in pruritus and palliative care regarding unpublished data.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) assessing the effects of different pharmacological treatments, compared with a placebo, no treatment, or an alternative treatment, for preventing or treating pruritus in palliative care patients.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed the identified titles and abstracts, performed data extraction and assessed the risk of bias and methodological quality. We summarised the results descriptively and quantitatively (meta-analyses) according to the different pharmacological interventions and the diseases associated with pruritus. We assessed the evidence using GRADE (Grading of Recommendations Assessment, Development and Evaluation) and created 10 'Summary of findings' tables.

MAIN RESULTS

In total, we included 50 studies and 1916 participants in the review. We added 10 studies with 627 participants for this update. Altogether, we included 39 different treatments for pruritus in four different patient groups.The overall risk of bias profile was heterogeneous and ranged from high to low risk. However, 48 studies (96%) had a high risk of bias due to low sample size (i.e. fewer than 50 participants per treatment arm). Using GRADE criteria, we downgraded our judgement on the quality of evidence to moderate in seven and to low in three comparisons for our primary outcome (pruritus), mainly due to imprecision and risk of bias.In palliative care participants with pruritus of different nature, the treatment with the drug paroxetine, a selective serotonin reuptake inhibitor, reduced pruritus by 0.78 points (numerical analogue scale from 0 to 10; 95% confidence interval (CI) -1.19 to -0.37; one RCT, N = 48, quality of evidence: moderate) compared to placebo.For participants suffering from uraemic pruritus (UP), gabapentin was more effective than placebo (visual analogue scale (VAS): 0 to 10), mean difference (MD) -5.91, 95% CI -6.87 to -4.96; two RCTs, N = 118, quality of evidence: moderate). The κ-opioid receptor agonist nalfurafine showed amelioration of UP (VAS 0 to 10, MD -0.95, 95% CI -1.32 to -0.58; three RCTs, N = 422, quality of evidence: moderate) and only few adverse events. Moreover, cromolyn sodium relieved UP participants from pruritus by 2.94 points on the VAS (0 to 10) (95% CI -4.04 to -1.83; two RCTs, N = 100, quality of evidence: moderate) compared to placebo.In participants with cholestatic pruritus (CP), data favoured rifampin (VAS: 0 to 100, MD -24.64, 95% CI -31.08 to -18.21; two RCTs, N = 42, quality of evidence: low) and flumecinol (RR > 1 favours treatment group; RR 1.89, 95% CI 1.05 to 3.39; two RCTs, N = 69, quality of evidence: low) and showed a low incidence of adverse events in comparison with placebo. The opioid antagonist naltrexone reduced pruritus for participants with CP (VAS: 0 to 10, MD -2.26, 95% CI -3.19 to -1.33; two RCTs, N = 52, quality of evidence: moderate) compared to placebo. However, effects in participants with UP were inconclusive (percentage difference -12.30%, 95% CI -25.82% to 1.22%, one RCT, N = 32). Furthermore, large doses of opioid antagonists (e.g. naltrexone) could be inappropriate in palliative care patients because of the risk of reducing analgesia.For participants with HIV-associated pruritus, it is uncertain whether drug treatment with hydroxyzine hydrochloride, pentoxifylline, triamcinolone or indomethacin reduces pruritus because the evidence was of very low quality (e.g. small sample size, lack of blinding).

AUTHORS' CONCLUSIONS

Different interventions tended to be effective for CP and UP. However, therapies for patients with malignancies are still lacking. Due to the small sample sizes in most meta-analyses and the heterogeneous methodological quality of the included trials, the results should be interpreted cautiously in terms of generalisability.

Skin disorders in peritoneal dialysis patients: An underdiagnosed subject

AIM: To examine all skin changes in peritoneal dialysis (PD) patients followed up in our unit.

METHODS: Patients on PD program for at least three months without any known chronic skin disease were included in the study. Patients with already diagnosed skin disease, those who have systemic diseases that may cause skin lesions, patients with malignancies and those who did not give informed consent were excluded from the study. All patients were examined by the same predetermined dermatologist with all findings recorded. The demographic, clinical and laboratory data including measures of dialysis adequacy of patients were recorded also. Statistical Package for Social Sciences (SPSS) for Windows 16.0 standard version was used for statistical analysis.

RESULTS: Among the patients followed up in our PD unit, those without exclusion criteria who gave informed consent, 38 patients were included in the study with male/female ratio and mean age of 26/12 and 50.3 ± 13.7 years, respectively. The duration of CKD was 7.86 ± 4.16 years and the mean PD duration was 47.1 ± 29.6 mo. Primary kidney disease was diabetic nephropathy in 11, nephrosclerosis in six, uropathologies in four, chronic glomerulonephritis in three, chronic pyelonephritis in three, autosomal dominant polycystic kidney disease in three patients while cause was unknown in eight patients. All patients except for one patient had at least one skin lesion. Loss of lunula, onychomycosis and tinea pedis are the most frequent skin disorders recorded in the study group. Diabetic patients had tinea pedis more frequently (P = 0.045). No relationship of skin findings was detected with primary renal diseases, comorbidities and medications that the patients were using.

CONCLUSION: Skin abnormalities are common in in PD patients. The most frequent skin pathologies are onychomycosis and tinea pedis which must not be overlooked.

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.

Comparison of Gabapentin and Ketotifen in Treatment of Uremic Pruritus in Hemodialysis Patients

Objectives:

Uremic pruritus is a common problem in hemodialysis patients. Several treatments have been used for decreasing itching in these patients. Gabapentin and ketotifen are two drugs used for treating uremic patients. The aim of this study was to compare gabapentin and ketotifen in treatment of uremic pruritus in hemodialysis patients.

Methods:

In this double-blind randomized clinical trial, 52 hemodialysis patients with uremic pruritus referred to 5azarTeaching Hospital in Gorgan in 2013 were studied. Patients were randomly assigned to two groups of 26 subjects (groups G and K). In group G, patients treated with gabapentin capsules 100 mg daily for 2 weeks, and in Group K, patients treated with ketotifen 1 mg twice daily for 2 weeks. Before and at the end of study, pruritus severity was determined based on Shiratori’s severity scores. Collected data were analyzed by SPSS-21 statistical software.

Results:

There was no significant different between two groups in the age and sex. After two weeks of treatment, severity of pruritus was significantly reduced in both groups (88.4% in group G vs. 76.9% in group K). Gabapentin compared with ketotifen had a better effect on improving itching in the age group of 30-60 years and in males. 5 patients (19.2%) in both groups suffered from drowsiness and dizziness, but no serious side effects were observed.

Conclusions:

The results showed that gabapentin and ketotifen significantly improved pruritus in hemodialysis patients, and no significant difference was observed between two groups.

Gabapentin for uremic pruritus in hemodialysis patients: a qualitative systematic review

PURPOSE OF THE REVIEW

Uremic pruritus (UP) is a common discomfort of dialysis-dependent end-stage renal disease. Some studies suggest a neuropathic cause of UP. Gabapentin, an anticonvulsant, has shown promising results as an emerging drug to treat this condition.

OBJECTIVE

An updated qualitative systematic review was conducted to evaluate its efficacy and safety in hemodialysis patients.

SOURCE OF INFORMATION

Ovid MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, Clinicaltrials.gov, and Google Scholar through June 2015 were used as sources of information.

PATIENTS

Patients are adult hemodialysis patients receiving gabapentin for UP.

METHODS

All randomized controlled trials (RCTs), quasi-RCTs, observational studies, open-label studies, and retrospective studies were included. Case series and case reports were excluded. All descriptions and data were extracted independently by two authors.

RESULTS

Seven studies evaluating gabapentin with a total of 179 patients were included. Most patients were refractory to antihistamines and topical emollients. Statistically significant favorable outcomes on pruritus scores were found in six studies. Five studies evaluated antipruritic efficacy based on a 10-point visual analog scale (VAS), and improvements in the range of an absolute decrease of 5.7 to 9.4 points from baseline were achieved on average by 3-8 weeks of treatment. Side effects are common with six studies reporting at least 26 incidences of side effects such as somnolence, dizziness, and fatigue. A total of four patients reportedly discontinued gabapentin due to intolerability.

LIMITATIONS

Our review is limited by the inclusion of generally small, lower quality studies that lacked comparator groups or were open-label studies. Since the first two randomized controlled trials were published, no further high-quality studies have been conducted.

IMPLICATIONS

Our review supports a trial of gabapentin for the management of UP in hemodialysis patients refractory to antihistamines and/or emollients. The results should be interpreted cautiously due to the lower quality of included studies. We recommend a starting dose of 100 mg orally after hemodialysis to minimize adverse events in this population.

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.

Aluminum overload hampers symptom improvement following parathyroidectomy for secondary hyperparathyroidism

BACKGROUND

Aluminum overload and accumulation in tissues may lead to skeletal, hematological, and neurological toxicity. The aim of this study was to assess the effects of serum aluminum levels on presentations, postoperative recovery, and symptom improvement in patients undergoing parathyroidectomy for secondary hyperparathyroidism.

METHODS

From 2008 to 2013, all patients with end-stage renal disease undergoing initial parathyroidectomy were included in the study. Serum aluminum level was measured preoperatively and/or within 1 week after surgery. Preoperative and postoperative biochemical profile and symptoms were compared between the low and high aluminum groups.

RESULTS

A total of 176 patients were included in the study. Of these, 38 (22 %) patients had serum aluminum levels higher than 20 μg/L. A higher percentage of patients in the high aluminum group were on peritoneal dialysis than in the low aluminum group (24 vs. 4 %, p = 0.001). Both groups had similar bone mineral density and changes in biochemical profiles. The preoperative parathyroidectomy assessment of symptoms (PAS) score was not associated with serum aluminum levels (p = 0.349), whereas the postoperative PAS score showed positive association (p = 0.005). There was a negative association between serum aluminum levels and the improvement of total PAS scores (p = 0.001). The high aluminum group had more residual symptoms in three aspects: bone pain (p = 0.038), difficulty getting out of a chair or car (p = 0.045), and pruritus (p = 0.041).

CONCLUSIONS

A high serum aluminum level was associated with reduced symptom improvement in patients undergoing parathyroidectomy for secondary hyperparathyroidism.

Use of Antiepileptic Drugs in Patients with Chronic Kidney Disease and End Stage Renal Disease

Epilepsy is a disorder with an approximate worldwide prevalence of 1%. Due to complexities of metabolism, protein-binding, renal elimination, and other pharmacokinetic parameters, the dosing of antiepileptic drugs (AEDs) in patients with chronic kidney disease (CKD) or end stage renal disease (ESRD) deserves special attention. This is a review of the most commonly prescribed AEDs with special focus on their indication, pharmacokinetics, and unique considerations for use in patients with CKD and ESRD. A review of their renal toxicities is also included.

Pharmacokinetics of nalbuphine hydrochloride extended release tablets in hemodialysis patients with exploratory effect on pruritus

BACKGROUND

Uremic pruritus is a common and deleterious condition among hemodialysis (HD) patients. Central gating of μ/κ opiate circuitry plays an important role in mediating and countering pruritogenic sensation. The objective of this study was to assess the safety and pharmacokinetics (PK) of the mixed μ-antagonist/κ-agonist nalbuphine, administered orally as nalbuphine HCl extended release (ER) tablets in HD patients, and explore its effect on pruritus.

METHODS

In this open-label multiple escalating dose study, 15 HD patients with pruritus and 9 matched healthy subjects were enrolled. Nalbuphine HCl ER dose was escalated from 30 mg QD to 240 mg BID over 15 days. A full PK profile was obtained under dialysis and non-dialysis conditions as a function of dose. Clearance during dialysis was determined by sampling dialysate and arterial/venous blood during dialysis. Pruritus severity was assessed twice daily using a Visual Analog Scale (VAS). Safety monitoring included extensive monitoring of EKG, blood pressure, and pulse oximetry.

RESULTS

In HD patients, nalbuphine concentration peaked within 4-9 hours and attained steady state within 2-3 days, with no significant accumulation. Mean half-life was 14.2 hours, mean Cmax and AUCtau ranged between 13 and 83 ng/mL and 118 and 761 ng∙h/mL, respectively, with exposure increasing in a nearly dose-proportional fashion. Exposure in HD patients was about 2-fold higher than in healthy subjects. There was no meaningful difference between exposure on dialysis and non-dialysis days with 1% or less of the dose removed by dialysis. Nalbuphine suppressed itch in a dose-dependent manner, reducing mean VAS score from 4.0 to 1.2 at 180 mg and 0.4 at 240 mg.

CONCLUSIONS

Nalbuphine HCl ER tablets can be safely administered to HD patients without dose adjustment up to 240 mg BID and may hold promise in treating uremic pruritus.

Nalfurafine suppresses pruritogen- and touch-evoked scratching behavior in models of acute and chronic itch in mice

The kappa-opioid agonist, nalfurafine, has been approved in Japan for treatment of itch in patients with chronic kidney disease. We presently investigated if systemic administration of nalfurafine inhibited ongoing or touch-evoked scratching behavior (alloknesis) following acute intradermal injection of histamine or the non-histaminergic itch mediator, chloroquine, in mice. We also investigated if nalfurafine suppressed spontaneous or touch-evoked scratching in an experimental model of chronic dry skin itch. Nalfurafine reduced scratching evoked by histamine and chloroquine. Following acute histamine, but not chloroquine, low-threshold mechanical stimuli reliably elicited directed hindlimb scratching behavior, which was significantly attenuated by nalfurafine. In mice with experimental dry skin, nalfurafine abolished spontaneous scratching but had no effect on alloknesis. Nalfurafine thus appears to be a promising treatment for acute itch as well as ongoing itch of dry skin.

Effects of turmeric on uremic pruritus in end stage renal disease patients: a double-blind randomized clinical trial

BACKGROUND

Uremic pruritus as a symptom that affects hemodialysis (HD) patients can decrease the quality of life and increase morbidity in these patients. The aim of this study was to evaluate the effects of turmeric on uremic pruritus in HD patients.

SUBJECTS AND METHODS

This was a double-blind placebo-controlled trial conducted on 100 HD patients suffering from pruritus. Patients (mean age 53.3 ± 15.8 years) were randomized into two groups: turmeric and placebo. The pruritus score and biochemical determinants including high-sensitivity C-reactive protein (hs-CRP) were compared before and at the end of the study between the two groups.

RESULTS

The mean decrease in hs-CRP was significantly higher in the turmeric than the placebo group (-0.8 ± 2.6 vs. 0.4 ± 8.7 mg/l, p = 0.012). Also reduction of pruritus scores was greater in the turmeric than the placebo group (13.6 ± 2.6 vs. 7.2 ± 2.6, p = 0.001). No side effect was observed during the study due to the use of turmeric.

CONCLUSIONS

This study demonstrates the possible efficacy of turmeric in decreasing hs-CRP and uremic pruritus in end stage renal disease patients. Future studies are needed to further evaluate the efficacy and safety of turmeric.