Optimal dialysis improves uremic pruritus

Identification and Management of CKD-Associated Pruritus: Current Insights

Chronic kidney disease-associated pruritus (CKD-aP) is a frequent and distressing problem for individuals with chronic kidney disease (CKD) and end-stage renal disease. It affects around 20% of those with CKD and 40% of those with end-stage renal disease. Despite its clear association with poorer psychosocial and medical outcomes, it is often underreported by patients and frequently remains unnoticed by healthcare providers. This is likely due to uncertainty regarding its diagnosis and treatment. Most commonly, CKD-aP could be screened with questionnaires like the KDQoL-36 and WI-NRS, chosen for their simplicity and ease of use. Prior treatment studies of CKD-aP were mostly limited by noncontrolled design and small sample size. First CKD-aP medication - difelikefalin a powerful, new therapeutic option was approved by Federal Drug Administration (FDA) in 2021 and European Medicines Agency (EMA) in 2022. Recent expert opinions, clinical trials and metanalysis identified difelikefalin and gabapentinoids as medications of choice in treatment of CKD-aP. All these findings improved current understanding and management of this condition.

Pruritus Severity and Serum Phosphate in CKD: A Post Hoc Analysis of Difelikefalin Studies

Key Points

No correlation was observed between pruritus severity and serum phosphate or response to placebo or difelikefalin in patients with CKD-associated pruritus undergoing hemodialysis. Difelikefalin improved itch versus placebo irrespective of baseline serum phosphate.

Background

CKD-associated pruritus (CKD-aP) has historically been associated with elevated serum phosphate (sP). Difelikefalin is a novel antipruritic agent approved for the treatment of moderate-to-severe CKD-aP in adults undergoing hemodialysis. This post hoc analysis used data from phase 3 difelikefalin studies (KALM-1, KALM-2, and open-label Study 3105) to assess the role of sP in the pathogenesis of CKD-aP and whether difelikefalin ameliorates CKD-aP in patients with and without elevated sP.

Methods

Patients with moderate-to-severe CKD-aP undergoing hemodialysis with baseline sP data were included in the analysis (KALM-1 and KALM-2, n =845; Study 3105, n =220). Assessments included correlation between 24-hour Worst Itching Intensity Numerical Rating Scale (WI-NRS) score and sP.

Results

In KALM-1 and KALM-2, baseline characteristics in the overall population were similar between patients with sP ≤5.5 and >5.5 mg/dl; no significant correlation was observed between WI-NRS and sP at baseline or in week 12. In patients receiving placebo, no correlation was observed between WI-NRS and sP at baseline or between their change from baseline to week 12 (all P < 0.05). Clinically meaningful (≥3-point) reductions from baseline to week 12 in WI-NRS scores were reported by more patients receiving placebo with baseline sP ≤5.5 mg/dl than >5.5 mg/dl (least squares mean 37.2% versus 27.4%; odds ratio [95% confidence interval], 0.63 [0.41 to 0.97]; P = 0.04). A greater proportion of patients treated with difelikefalin achieved a ≥3-point WI-NRS reduction from baseline to week 12 versus placebo and was similar between sP ≤5.5 and >5.5 mg/dl subgroups (least squares means 51.1% versus 57.6% [P = 0.20]). No significant relationships between sP and WI-NRS in patients receiving difelikefalin were identified in Study 3105 at any time point.

Conclusions

No correlation was observed between pruritus severity and sP or response to placebo or difelikefalin in patients with CKD-aP undergoing hemodialysis. Difelikefalin improved itch versus placebo irrespective of baseline sP.

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.

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.

Etiopathogenesis of chronic kidney disease-associated pruritus: putting the pieces of the puzzle together

Defined as the unpleasant sensation that causes the desire to scratch, pruritus is the most common skin symptom associated with uremia and appears in almost half of patients with advanced chronic kidney disease (CKD). Beyond its direct impact on quality of life, CKD-associated pruritus (CKD-aP) is an independent predictor of mortality that also has a synergistic effect with other quality of life-related symptoms, such as insomnia, depression, and anxiety. Although different mechanisms have been proposed to explain the origin of Pa-ERC, its etiopathogenesis is still not fully understood. Since new therapeutic targets have been identified and several clinical trials have recently shown promising results, our current understanding of the interrelationships has expanded significantly and the pathophysiological mechanisms underlying CKD-aP are now considered to be multifactorial. The potential triggers of pruritus in patients with CKD are discussed in this review, including hypotheses about skin xerosis, accumulation of uremic toxins, dysregulation of the immune system and systemic inflammation, uremic neuropathy, and imbalances in the endogenous opioid system. Other non-uremic causes of pruritus are also discussed, with the aim of guiding the physicians to apply an adequate aetiopathogenic approach to CKD-aP in their day-to-day clinical practice.

Obstacles to Early Diagnosis and Treatment of Pruritus in Patients with Chronic Kidney Disease: Current Perspectives

Chronic kidney disease-associated pruritus (CKD-aP) is a common condition amongst patients with advanced chronic kidney disease (CKD). Several studies have confirmed that more than four out of ten early-stage CKD patients suffer from this condition, while its prevalence among CKD patients on dialysis reaches up to seven out of ten. It is noted to be associated with other disabling symptoms and serious outcomes. It has significant impact on sleep, mood, daily activities, and quality of life of CKD patients, and increased mortality risk of patients on hemodialysis. The Dialysis Outcomes and Practice Patterns Study found 17% higher mortality among patients with moderate to extreme pruritus compared with patients with no or mild pruritus. Despite its high prevalence, ill-effect, and suffering associated with it, CKD-aP remains surprisingly under-reported on the patient's part and under-recognized by the healthcare team. Even upon being noticed, it remains unattended and poorly treated. Its etiopathogenesis is complex and not fully understood. Many treatment options are available but good quality evidence about most of those is absent, and to date, only two medications are approved for use in this condition. While a validated guideline is very much required for the benefit of the patients and caretakers, further research on several aspects of this issue is required.

Uremic Pruritus: From Diagnosis to Treatment

Uremic pruritus, or chronic kidney disease-associated pruritus, is common, bothersome, and sometimes debilitating in patients with chronic kidney disease or end-stage renal disease. Due to its variable clinical manifestations, the diagnosis of uremic pruritus requires exquisite evaluation. Excluding itch resulting from other dermatological causes as well as other systemic conditions is essential for a proper diagnosis. The pathophysiology of uremic pruritus remains uncertain. Hypotheses including toxin deposition, immune system dysregulation, peripheral neuropathy, and opioid imbalance are supposed. This review summarizes the way to accurately diagnose uremic pruritus and describes the latest treatment options.

Pruritus: A Sensory Symptom Generated in Cutaneous Immuno-Neuronal Crosstalk

Pruritus or itch generated in the skin is one of the most widespread symptoms associated with various dermatological and systemic (immunological) conditions. Although many details about the molecular mechanisms of the development of both acute and chronic itch were uncovered in the last 2 decades, our understanding is still incomplete and the clinical management of pruritic conditions is one of the biggest challenges in daily dermatological practice. Recent research revealed molecular interactions between pruriceptive sensory neurons and surrounding cutaneous cell types including keratinocytes, as well as resident and transient cells of innate and adaptive immunity. Especially in inflammatory conditions, these cutaneous cells can produce various mediators, which can contribute to the excitation of pruriceptive sensory fibers resulting in itch sensation. There also exists significant communication in the opposite direction: sensory neurons can release mediators that maintain an inflamed, pruritic tissue-environment. In this review, we summarize the current knowledge about the sensory transduction of pruritus detailing the local intercellular interactions that generate itch. We especially emphasize the role of various pruritic mediators in the bidirectional crosstalk between cutaneous non-neuronal cells and sensory fibers. We also list various dermatoses and immunological conditions associated with itch, and discuss the potential immune-neuronal interactions promoting the development of pruritus in the particular diseases. These data may unveil putative new targets for antipruritic pharmacological interventions.

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.

Clinical management of chronic kidney disease-associated pruritus: current treatment options and future approaches

Chronic kidney disease (CKD)-associated pruritus (CKD-aP) is an underdiagnosed yet severely distressing condition that impacts 60% of patients on dialysis and many nondialysis patients with Stages 3–5 CKD. However, despite its high prevalence, there are currently limited treatment options available for these patients and a lack of treatment guidelines for clinicians. In this manuscript, we reviewed the available literature in order to evaluate the current management and treatment options for CKD-aP, including dialysis management, topical treatments, gabapentinoids, opioids and alternative medicine. We also review the available data on CKD-aP treatments in development and propose new guidelines for managing patients with CKD-aP.

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.

[Pruritus associated chronic kidney disease]

Pruritus associated with chronic kidney disease is a frequent and disabling symptom in patients with severe chronic kidney disease treated by dialysis. It is associated with a poor quality of life, an increased risk of comorbidities and even mortality. Nevertheless, its prevalence is underestimated by nephrologists. The pathophysiology of pruritus associated with chronic kidney disease is not well understood, but several mechanisms seem to contribute to its occurrence: accumulation and skin deposition of uremic toxins, peripheral neuropathy causing an activation of the pruritogenic cowhage pathway, chronic microinflammation, opioid imbalance, and kidney disease-related skin xerosis. Optimization of the treatment of chronic kidney disease treatment, of dialysis parameters, and general skin care measures should always be performed prior to the introduction of systemic therapy targeting one or more of these mechanisms. The available therapeutic trials remain mostly at high risk of bias, with small patient numbers. Gabapentinoids are the molecules recommended as first-line therapy. Peripheral opioid agonists could find a place of choice in the treatment of pruritus associated with chronic kidney disease and will soon be available in France. The low level of evidence for the other molecules does not currently allow us to specify a second-line treatment for this condition.

Chronic Kidney Disease-Associated Pruritus

Pruritus is a distressing condition associated with end-stage renal disease (ESRD), advanced chronic kidney disease (CKD), as well as maintenance dialysis and adversely affects the quality of life (QOL) of these patients. It has been reported to range from 20% to as high as 90%. The mechanism of CKD-associated pruritus (CKD-aP) has not been clearly identified, and many theories have been proposed to explain it. Many risk factors have been found to be associated with CKD-aP. The pruritus in CKD presents with diverse clinical features, and there are no set features to diagnose it.The patients with CKD-aP are mainly treated by nephrologists, primary care doctors, and dermatologists. Many treatments have been tried but nothing has been effective. The search of literature included peer-reviewed articles, including clinical trials and scientific reviews. Literature was identified through March 2021, and references of respective articles and only articles published in the English language were included.

Self-reported Pruritus and Clinical, Dialysis-Related, and Patient-Reported Outcomes in Hemodialysis Patients

RATIONALE & OBJECTIVE

Chronic kidney disease (CKD)-associated pruritus, generalized itching related to CKD, affects many aspects of hemodialysis patients' lives. However, information regarding the relationship between pruritus and several key outcomes in hemodialysis patients remains limited.

STUDY DESIGN

Prospective cohort.

SETTING & PARTICIPANTS

23,264 hemodialysis patients from 21 countries in the Dialysis Outcomes and Practice Patterns Study (DOPPS) phases 4 to 6 (2009-2018).

EXPOSURE

Pruritus severity, based on self-reported degree to which patients were bothered by itchy skin (5-category ordinal scale from "not at all" to "extremely").

OUTCOMES

Clinical, dialysis-related, and patient-reported outcomes.

ANALYTICAL APPROACH

Cox regression for time-to-event outcomes and modified Poisson regression for binary outcomes, adjusted for potential confounders.

RESULTS

The proportion of patients at least moderately bothered by pruritus was 37%, and 7% were extremely bothered. Compared with the reference group ("not at all"), the adjusted mortality HR for patients extremely bothered by pruritus was 1.24 (95% CI, 1.08-1.41). Rates of cardiovascular and infection-related deaths and hospitalizations were also higher for patients extremely versus not at all bothered by pruritus (HR range, 1.17-1.44). Patients extremely bothered by pruritus were also more likely to withdraw from dialysis and miss hemodialysis sessions and were less likely to be employed. Strong monotonic associations were observed between pruritus severity and longer recovery time from a hemodialysis session, lower physical and mental quality of life, increased depressive symptoms, and poorer sleep quality.

LIMITATIONS

Residual confounding, recall bias, nonresponse bias.

CONCLUSIONS

Our findings demonstrate how diverse and far-reaching poor outcomes are for patients who experience CKD-associated pruritus, specifically those with more severe pruritus. There is need for change in practice patterns internationally to effectively identify and treat patients with pruritus to reduce symptom burden and improve quality of life and possibly even survival.

Interventions for itch in people with advanced chronic kidney disease

BACKGROUND

Itch in patients with chronic kidney disease (CKD) is common, often very distressing and associated with depression, reduced quality of life, and increased death. The most common first-line treatment has been the use of antihistamines despite the lack of substantial evidence for its use for uraemic itch. Few recommendations and guidelines exist for treatment.

OBJECTIVES

We aimed to determine: 1) the benefits and harms (both absolute and relative) of all topical and systemic interventions for the treatment of uraemic itch, either alone or in combination, when compared with placebo or standard care; and, 2) the dose strength or frequency, stage of kidney disease or method of dialysis used (where applicable) in cases where the effects of these interventions vary depending on co-interventions.

SEARCH METHODS

We searched the Cochrane Kidney and Transplant Register of Studies up to 17 December 2019 through contact with the Information Specialist using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Register (ICTRP) Search Portal and ClinicalTrials.gov.

SELECTION CRITERIA

Randomised controlled trials (RCTs) in adults with CKD stages 4 or 5 comparing treatments (pharmacological, topical, exposure, dialysis modality) for CKD associated itch to either placebo or other established treatments.

DATA COLLECTION AND ANALYSIS

Two authors independently abstracted study data and assessed study quality. Data were analysed using a random effects meta-analysis design estimating the relative effects of treatment versus placebo. Estimates of the relative effects between treatments are included where possible. For continuous measures of severity of itch up to three months, mean difference (MD) or standardised mean difference (SMD) were used. When reported, adverse effects were tabulated. The certainty of the evidence was estimated using GRADE.

MAIN RESULTS

Ninety-two RCTs, randomising 4466 participants were included. Fifty-eight studies (3285 participants) provided sufficient data to be meta-analysed. Of these, 30 compared an intervention to a placebo or control. The 10 cm Visual Analogue Scale (VAS) was the dominant instrument utilized for itch reporting and the Duo score was used in a minority of studies. GABA analogues including, gabapentin and pregabalin, reduce itch in patients with CKD (5 studies, 297 participants: 4.95 cm reduction, 95% CI 5.46 to 4.44 lower in VAS compared to placebo; high certainty evidence). Kappa opioid agonists, including nalfurafine also reduced itch in this population (6 studies, 661 participants: 1.05 cm reduction, 95% CI 1.40 to 0.71 lower in VAS compared to placebo; high certainty evidence). Ondansetron had little or no effect on itch scores (3 studies, 183 participants: 0.38 cm reduction, 95% CI 1.04 lower to 0.29 higher in VAS compared to placebo; high certainty evidence). Reduction in the severity of itch was reported with oral montelukast, turmeric, zinc sulfate and topical capsaicin. For all other interventions, the certainty of the evidence was low to moderate, and the interventions had uncertain effects on uraemic pruritus. Six studies have disclosed significant financial support from their respective manufacturers, six were affected by lack of blinding, and 11 studies have 15 participants or less. Older, smaller RCTs often failed to follow intention-to-treat protocols with unexplained dropouts after randomisation. Adverse effects were generally poorly and inconsistently reported across all RCTs. No severe adverse events were reported for any intervention.

AUTHORS' CONCLUSIONS

The RCTs of this meta-analysis contain a large array of interventions with a diverse set of comparators. For many interventions, trials are sparse. This served to make informative meta-analysis challenging. Of all treatments for uraemic pruritus, gabapentinoids (gabapentin and pregabalin) were the most studied and show the greatest reduction in itch scores. Further RCTs, even of the scale of the largest trials included in this review, are unlikely to significantly change this finding. Kappa-opioid agonists (mainly nalfurafine) also may reduce itch, but indirect comparison suggests a much more modest effect in comparison to GABA analogues. Evidence for oral montelukast, turmeric, zinc sulfate, and topical capsaicin also showed an itch score reduction. However, these reductions were reported in small studies, and warrant further investigation. Ondansetron did not reduce itch. It is somewhat unlikely that a further study of ondansetron will change this result.

Elevated interleukin 31 serum levels in hemodialysis patients are associated with uremic pruritus

INTRODUCTION

Uremic pruritus is a multifactorial devastating complication of renal failure, which has a significant negative impact on patients' quality of life including medical, psychological, as well as social aspects. It is also associated with an increased mortality in dialysis patients.

METHODS

A cross sectional study evaluating the traditional risk factors for uremic pruritus (UP) - using pruritus grading system (PGS) and visual analogue scale (VAS) - as well as measuring the serum levels of different inflammatory cytokines (ILs 13, 31 and 33) in chronic hemodialysis and healthy controls, in a tertiary referral hospital.

RESULTS

65 hemodialysis (HD) patients and 49 heathy controls were enrolled in the study. The mean age for the HD patients was 43.4 years (SD ± 21.3), and 31.5 years (SD ± 11.1) for the control group. The most common cause for End Stage Renal Disease (ESRD) was diabetes mellitus (DM) 27.7%. The mean PGS score in HD patients was 5.92 (SD ± 2.9); 50% had mild itch, 43.8% moderate itch and 6.2% had severe itch. The mean serum levels for IL-13 was 8674.3 pg/ml (SD ± 4353.9), serum levels of IL-31 were 150.7 pg/ml (SD ± 178.2) and for IL-33 it was 42850.5 pg/ml (SD ± 11370.7) in hemodialysis patients; in comparison to serum levels of 7913.4 pg/ml (SD ± 3454.1), 67.1 pg/ml (SD ± 71.9) and 44875.9 pg/ml (SD ± 12114.6), respectively in the control group. IL-31 level was significantly higher in HD patients than in the control group (P = 0.0001), while the difference in the levels of IL-13 and IL-33 between the two groups were not statistically significant (P = 0.41 and 0.18, respectively). IL-13 had a statistically significant relationship with the itch score (P = 0.014) and the severity of itch (P = 0.03), while IL-31 and IL-33 were not statistically significant.

CONCLUSION

UP is a complex and multifactorial problem. In patients with UP the high levels of IL-31 indicates a possible role in pathogenesis. IL-13 serum level on the other hand may be related to the severity of itch in these patients. Optimizing dialysis and targeting these cytokines may provide a potential therapeutic option especially in refractory UP. Further studies addressing these cytokines and their levels in response to various treatments may provide additional information on UP.

Have We Just Scratched the Surface? A Narrative Review of Uremic Pruritus in 2020

Purpose of review:

Uremic pruritus is a highly prevalent and debilitating symptom in patients with chronic kidney disease (CKD) and end-stage kidney disease (ESKD). The purpose of this review is to examine current evidence on the mechanisms and treatments of pruritus in CKD and highlight promising areas for future research.

Sources of information:

Published literature, including randomized controlled trials, cohort studies, case reports, and review articles, was searched for evidence pertaining to the pathophysiology and treatment of uremic pruritus.

Methods:

A comprehensive narrative review was conducted to explore the molecular mechanisms underlying uremic pruritus, as well as the evidence (or lack thereof) supporting pharmacological and nonpharmacological treatments for uremic pruritus. The potential role of patient sex in the pathophysiology and management of uremic pruritus is also discussed.

Key findings:

The pathophysiology of uremic pruritus involves a complex interplay of uremic toxins, systemic inflammation, mast cell activation, and imbalance of opioid receptors. Classic treatment strategies for uremic pruritus include optimization of dialysis parameters, amelioration of CKD-related mineral and bone disease, topical emollients and analgesics, antihistamines, the anticonvulsant medications gabapentin and pregabalin, and ultraviolet light B (UV-B) phototherapy. Strong data to support many of these classical treatments for uremic pruritus are limited. Newly evolving treatment approaches for uremic pruritus include opioid receptor modulators, neurokinin-1 inhibitors, and cannabinoids. Further studies regarding their efficacy, pharmacodynamics, and safety in the CKD and ESKD population are needed before these agents are accepted into widespread use. Additional nonpharmacological strategies aimed at treating uremic pruritus include psychotherapy, acupuncture, omega-3 fatty acids, and exercise. Finally, sex differences may exist regarding uremic pruritus, but studies directly addressing sex-specific mechanisms of uremic pruritus remain absent.

Limitations:

High-quality evidence in the management of uremic pruritus remains lacking. Most recommendations are based on expert opinion or studies involving small numbers of patients. In addition, our understanding of the pathophysiological mechanisms behind uremic pruritus is incomplete and continues to evolve over time.

Implications:

Uremic pruritus is a common symptom which reduces quality of life in CKD and ESKD. The identification of novel targeted treatment approaches may ease the burden of uremic pruritus in the future.

CKD-Associated Pruritus: New Insights Into Diagnosis, Pathogenesis, and Management

Chronic kidney disease–associated pruritus (CKD-aP) is a common, troubling and in some cases debilitating problem for patients with CKD and end-stage renal disease. Despite a prevalence rate of approximately 20% in CKD and 40% in end-stage renal disease, and a clear association with poorer psychosocial and medical outcomes, this condition is often underreported by patients and overlooked by health care providers. This is likely due, in part, to uncertainty regarding its pathogenesis and treatment. Most commonly, CKD-aP is attributed to toxin build-up, peripheral neuropathy, immune system dysregulation, or opioid dysregulation. Prior treatment studies of CKD-aP have targeted these potential etiologies but have been limited by noncontrolled design, small sample size, and non-uniform definitions of CKD-aP. Recently, several large, randomized controlled trials targeting opioid dysregulation have yielded promising results. These trials have spurred new hope for understanding and treating this condition.

Itching as the onset of pain (part 2)

Itching of the skin is a particularly unpleasant subjective sensation that causes the need to scratch. Physiological itching occurs in response to environmental irritants (friction, insect crawling, temperature changes, etc.) and disappears after elimination of the cause. Pathological itching is caused by changes in the skin or throughout the body and causes a strong need to get rid of itching by combing or any other method. Itching is a common symptom of local (dermatological) or general (systemic) disease. It can be limited (localized) or diffuse (generalized).One of the causes of itching is often noted endocrine diseases and metabolic disorders: hyper- and hypofunction of the thyroid gland, diabetes mellitus and hyperparathyroidism. In thyroid hyperfunction, generalized (inconstant and little-pronounced) itching of the skin is observed in the clinical picture only in 10 % of patients. It is accepted that itching of the skin in thyrotoxicosis syndrome is due to increased activity of kinin in combination with an increase in major metabolism and an increase in body and skin temperature (123).Itching caused by impaired bile secretion is characteristic of many diseases of the liver: primary biliary cirrhosis, sclerosing cholangitis, viral hepatitis caused by cholestasis medications and other causes of obstructive jaundice. It is in these cases that prurigo is usually generalized, but in some typical cases it is more pronounced on the feet and palms. With this pathology, itching is caused by obstruction of the biliary tract, however, and to this day, no close correlation has been found between serum bilirubin and the severity of itching.If it was previously thought that itching in pathology of the peripheral or central nervous system, such as multiple sclerosis, neuropathy, compression or irritation of nerves (e.g., paraesthetic dorsalgia, brachioradial itching) is also a significant symptom, then modern studies prove that in more cases, itching is not characteristic of most pathologies of the nervous system, so after a detailed anamnesis, examination and initial research, the patient should be referred to a related specialist, except in cases of about obvious postherpetic neuropathy, painless paresthesia, or brachioradial itching, which can often be guided in the provision of primary care.Instead, there are some psychological conditions and a number of psychiatric illnesses (obsessive-compulsive disorders, depression, and parasite illusions) that are most commonly diagnosed with the exclusion method. Neurotic squabbles are scattered on the body of the excorii, covered with scales that may occur in any area of the body that the patient may reach, but are often limited by limbs.

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.

Safety and efficacy of PG102P for the control of pruritus in patients undergoing hemodialysis (SNUG trial): study protocol for a randomized controlled trial

BACKGROUND

Pruritus in patients undergoing hemodialysis is a highly prevalent complication that affects quality of life. Several medications are currently used for the treatment of uremic pruritus, but these are not satisfactory. PG102P, which is prepared from Actinidia arguta, has an immune-modulating effect on pruritus. This trial is designed to assess the antipruritic effect of PG102P compared with placebo.

METHODS

This multicenter, randomized, double-blind, placebo-controlled clinical trial will include 80 patients undergoing hemodialysis. The patients will be randomized in a 1:1 ratio to a treatment group (PG102P 1.5 g/day) or a control group (placebo). The treatment will last for 8 weeks, followed by a 2-week observational period. During the observational period, all of the patients will maintain the antipruritic treatment previously used. The primary endpoint will be measured as the difference in visual analog scale between the groups before and after treatment. Secondary outcomes include serum levels of total immunoglobulin E, eosinophil cationic protein, potassium, calcium, phosphorus, intact parathyroid hormone, and blood eosinophil count between weeks 0 and 8. Kidney Disease and Quality of Life and Beck's Depression Inventory questionnaires will be conducted. Safety assessments and any adverse events that occur will also be evaluated.

DISCUSSION

The SNUG is a clinical study that aims to investigate the antipruritic effect of PG102P to ameliorate itching in patients undergoing hemodialysis.

TRIAL REGISTRATION

Clinical Trials.gov, NCT03576235. Registered on 4 July 2018.

Dermatologic manifestations in end stage renal disease

Skin manifestations are commonly seen in end stage renal disease (ESRD). Skin involvement in this population can be extensive and dramatically worsen quality of life. Close observation of the skin and nails of ESRD patients by clinicians allows for timely diagnosis and treatment, which ultimately improves quality of life and reduces mortality. In this article we focus on the cutaneous changes most commonly seen in ESRD patients. PubMed/Medline database search was done for published literature on skin manifestations in ESRD patients. All the available literature was reviewed and relevant articles were used to discuss about clinical features, pathogenesis, histology and treatment of each skin disorder in ESRD patients. Most commonly encountered skin manifestations in patients with ESRD are pruritus, xerosis, pigmentation changes, nail changes, perforating disorders, calcifying disorders, bullous dermatoses and nephrogenic systemic fibrosis. Skin manifestations in ESRD can be difficult to treat and multiple comorbidities in this patient population can exacerbate these disorders. Many of the treatment options are experimental with evidence largely derived from the case reports and small clinical trials. More large-scale trials are needed to firmly establish evidence based treatment guidelines. Prompt evaluation and management of these disorders improve morbidity and quality of life in ESRD patients.

Prevalence of chronic kidney disease-associated pruritus, and association with sleep quality among hemodialysis patients in Pakistan

Background

The prevalence of chronic kidney disease-associated pruritus (CKD-aP) varies from 22% to 84% among patients receiving hemodialysis. It occurs more frequently at night, and often affects patient’s sleep quality. CKD-aP is often unreported by patients, and many do not receive effective treatment. There is, however, a paucity of available data on the prevalence and impact of CKD-aP on patients receiving hemodialysis in Pakistan.

Methods

A multicenter cross-sectional study was undertaken from July 2016 to April 2017 at a tertiary care hospitals in Pakistan.

Results

354 patients undergoing hemodialysis were studied. 35.6% had CKD for 1–2 years, and 42.4% were receiving hemodialysis for 1–2 years. The prevalence of pruritus was 74%. The median [interquartile range] score for pruritus was 10.0 (out of possible 25) [8.0–12.0]; while the median [interquartile range] Pittsburgh Sleep Quality Index (PSQI) score was 8.0 (out of possible 21) [7.0–10.0]'. Pruritus was significantly correlated with the sleep score (r = 0.423, p<0.001). The results of the multivariate linear regression revealed a positive association between pruritus and age of patients (β = 0.031; 95% CI = 0.002–0.061; p = 0.038) and duration of CKD (β = -0.013; 95% CI = -0.023 –-0.003; p = 0.014). Similarly there was a positive association between sleep score and duration of CKD (β = 0.010; 95% CI = 0.002–0.019; p = 0.012) and pruritus (β = 0.143; 95% CI = 0.056–0.230; p = 0.001).

Conclusions

Chronic kidney disease-associated pruritus is very common in patients receiving hemodialysis in Pakistan. Pruritus is significantly associated with poor sleep quality.

Association Between Serum Aluminum Level and Uremic Pruritus in Hemodialysis Patients

Uremic pruritus (UP) is a common symptom in patients undergoing hemodialysis (HD). The pathogenesis of UP is complex. Aluminum (Al) is a common metal and is toxic to patients undergoing HD. Al is also a known human allergen which can induce immune reactions. However, the correlation between Al and UP remains unclear in dialysis patients. A total of 866 patients on maintenance HD were enrolled for analysis. The HD patients with higher serum Al levels had higher a prevalence of UP than those with lower serum Al levels. After adjusting for confounding variables, the serum Al level was significantly associated with UP. Overall, each 10-fold increase in serum Al level was associated with a 5.64-fold increase in the risk of developing UP in these subjects. The results of this cross-sectional study suggest that serum Al level may be associated with the development of UP in patients on maintenance HD.

Uremic Pruritus

Renal itch is a localized or generalized itch, affecting patients with chronic renal failure, where there is no primary skin disease and no systemic or psychological dysfunction that might cause pruritus. Uremic pruritus (UP) is an unpleasant sensation, rarely appearing in earlier stages of chronic kidney disease. Renal transplantation is the definite solution for that problem. The prevalence of UP has been reduced during the last years, possibly, due to a more efficient dialysis, with more biocompatible filters.

During the last decades a big number of substances were considered to be etiologic factors of UP, and an even bigger number of therapeutic substances appeared with promising potentials and conflicting results in the course of their use. The main reason for this disorientation is the lack of sound evidence on the pathogenetic mechanisms that may potentiate UP.

‘Inflammatory’ and ‘opioid’ hypothesis are the best studied and the reduction of UP is a fact. Nevertheless the mechanisms of the pathogenesis of UP are still under investigation and a long way has to be done in order to achieve more definite results.

International Comparisons of Prevalence, Awareness, and Treatment of Pruritus in People on Hemodialysis

BACKGROUND AND OBJECTIVES

Uremic pruritus in patients on hemodialysis is associated with depression, lower quality of life, and mortality. We studied the prevalence, awareness, and treatment of pruritus to assess how well this important condition is currently managed internationally.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Data from 35,452 patients on hemodialysis in up to 17 countries from the Dialysis Outcomes and Practice Patterns Study were analyzed to describe pruritus prevalence from 1996 to 2015. Data from 6256 patients and 268 medical directors in 17 countries in 2012-2015 were analyzed to describe predictors, effects, medical directors' awareness, and treatment of pruritus.

RESULTS

Patients very much or extremely bothered by itching declined from 28% in 1996 to 18% in 2015. In 2012-2015, among patients nearly always or always bothered by itching, pruritus had a major effect on work and social life; 18% used no treatment for pruritus, and 17% did not report itching to health care staff. In total, 69% of medical directors underestimated the prevalence of pruritus in their unit. Managing high serum phosphorus and low Kt/V was ranked as the most important intervention, but no relationship was found between these factors and pruritus; 57% of medical directors used oral antihistamines for first-line chronic treatment of pruritus. Gabapentin was used by 45% as first-, second-, or third-line treatment. Nalfurafine was only used in Japan.

CONCLUSIONS

The prevalence of pruritus in people on hemodialysis is decreasing but remains underestimated. Large numbers of patients on hemodialysis with severe pruritus do not receive treatment. There is wide variation in the use of unlicensed medications for the treatment of pruritus. These data provide a benchmark for initiatives to improve the management of uremic pruritus.

MULTIMEDIA

This article contains multimedia at https://vimeo.com/49458473This article contains multimedia at vimeo.com/49455976.

Chronic kidney disease-associated pruritus: impact on quality of life and current management challenges

Chronic kidney disease-associated pruritus (CKD-aP) is a distressing, often overlooked condition in patients with CKD and end-stage renal disease. It affects ~40% of patients with end-stage renal disease and has been associated with poor quality of life, poor sleep, depression, and mortality. Prevalence estimates vary based on the instruments used to diagnose CKD-aP, and standardized diagnostic instruments are sorely needed. Treatment studies have often yielded conflicting results. This is likely related to studies that are limited by small sample size, flawed designs, and nonstandardized diagnostic instruments. Several large well-designed treatment trials have recently been completed and may soon influence CKD-aP management.

Prevalence, Pattern and Association of Pruritus with Quality of Life in Chronic Kidney Disease Patients Attending Kidney Care Centre, Ondo City, Southwest Nigeria

BACKGROUND

Pruritus is a common cutaneous manifestation of chronic kidney disease (CKD). It is associated with poor sleep quality, anxiety and depression which may contribute to reduction in quality of life (QoL). Paying more attention to pruritus in CKD patients may improve their QoL, reduce kidney disease burden and mortality. This study determined the prevalence, pattern and association of pruritus with QoL in CKD patients.

MATERIALS AND METHODS

This was a cross-sectional descriptive study carried out in a Kidney Care Centre, Ondo City, Southwest Nigeria. The severity and intensity of pruritus and health-related QoL were assessed using validated instruments. P-value of < 0.05 was taken as significant.

RESULTS

There were 91 CKD subjects with a male:female ratio of 2.1:1. Sixty-nine (75.8%) of the CKD patients were not on dialysis while the remaining twenty-two (24.2%) were on maintenance hemodialysis (MHD). Thirty-nine (42.9%) of the CKD subjects had pruritus which was mild in 25(64.1%), moderate in 8(20.5%) and severe in 6(15.4%). Pruritus was more common in MHD patients compared to predialysis CKD patients(50%vs40.6%) p = 0.47. The median pruritus intensity score was also higher in MHD patients compared to predialysis CKD patients (40vs30) p = 0.51. There was no significant association between gender, age, aetiology of CKD, stage of CKD and pruritus. There was a significant correlation between QoL score and pruritus intensity. (p = < 0.001, r = 0.56).

CONCLUSION

Pruritus was common among our CKD subjects and it was not significantly associated with age, gender, stage or etiology of CKD. There was a significant association between impaired QoL and pruritus intensity.

[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.

Laboratory and dialysis characteristics in hemodialysis patients suffering from chronic itch--results from a representative cross-sectional study

BACKGROUND

A representative cross-sectional study showed that chronic itch (lasting for a minimum of 6 weeks) affects 25.2 % (point prevalence) of hemodialysis (HD) patients. Pathophysiology and etiology of chronic itch (CI) in HD are still unclear.

METHODS

We investigated 860 HD patients from a representative randomly selected cluster-sample considering the regional distributions of dialysis units in Germany. The current analyses report comorbidities, laboratory values and dialysis characteristics of HD patients in relation to CI.

RESULTS

Diabetes was the only comorbidity that was associated with the occurrence of itch but interestingly with less CI. Except for creatinine, phosphorus, and parathormone, there were no significant associations between the occurrence and characteristics of CI and any laboratory value. Kt/V was not associated with the presence of CI. Patients dialyzed with polyarylethersulfone-membrane showed significantly more CI in all prevalence estimates and those dialyzed with polysulfone-membrane were significantly less affected by CI.

CONCLUSIONS

Long-term follow-up studies will show if the type of dialysis membrane influences the development of CI in HD patients. It is most likely that several factors e.g. elevated parathormone, origin of end stage renal disease (ESRD), type of dialysis membrane, and a neuropathic component all contribute to the occurrence of CI in HD patients. Future research should consider a multifactorial origin of itch in HD.

Cutaneous abnormalities in patients with end stage renal failure on chronic hemodialysis. A study of 458 patients

BACKGROUND

Cutaneous manifestations occurring in patients with end stage renal failure on hemodialysis are polymorphic and diverse.

OBJECTIVE

The aim of our study was to assess the prevalence and characteristics of different cutaneous manifestations in patients on hemodialysis.

PATIENTS AND METHODS

We led a transverse investigation of all patients on hemodialysis in 12 haemodialysis centres of Sfax (Tunisia). We examined 458 patients (254 men and 204 women). The hemodialysis history ranged from 6 months to 24 years. A total of 394/458 (86%) patients had cutaneous abnormalities. These included pruritus (56.6% of patients), paleness (60.7%), xerosis (52.8%), hyperpigmentation or hypopigmentation (38.4%), venous dilation near the fistula (22.2%), eczema in the fistula area (14.8%), half-and-half nails (13.5%), onychodystrophy (6.1%), subungual hemorrhage (4.5%), leukonychia (4.5%), stomatitis (5.6%), xerostomia (3.2%), gingivitis (2.4%), uremic breath (2.1%), and skin calcificatins (0.4%). Nephrogenic fibrosing dermopathy was not detected in any of our patients.

CONCLUSIONS

Pruritus, paleness, dry skin as well as hyperpigmentation and hypopigmentation are the most frequent skin abnormalities observed in hemodialysis patients. The early recognition of some cutaneous conditions associated with end stage renal failure and hemodialysis may allow early therapeutic intervention and decrease morbidity.

Pruritus in hemodialysis patients: Results from the Japanese Dialysis Outcomes and Practice Patterns Study (JDOPPS)

Pruritus affects many patients undergoing hemodialysis (HD). In this study, pruritus and its relationship to morbidity, quality of life (QoL), sleep quality, and patient laboratory measures were analyzed in a large sample of Japanese patients undergoing HD. Severity of patient-reported pruritus symptoms experienced during a 4-week period was collected from 6480 Japanese patients undergoing HD in three phases of the Dialysis Outcomes and Practice Patterns Study (DOPPS; 1996-2008; 60-65 study facilities/phase). Adjusted linear and logistic regressions were used to identify associations of pruritus with treatment parameters and QoL outcomes. Adjusted Cox regressions examined the influence of pruritus severity on mortality. Moderate to extreme pruritus was experienced by 44% of prevalent patients undergoing HD in the Japanese Dialysis Outcomes and Practice Patterns Study. Many patient characteristics were significantly associated with pruritus, but this did not explain the large differences in pruritus among facilities (20-70%). Pruritus was slightly less common in patients starting HD than in patients on dialysis >1 year. Patients with moderate to extreme pruritus were more likely to feel drained (adjusted odds ratio = 2.2-5.8, P < 0.0001), have poor sleep quality (adjusted odds ratio = 1.9-3.7, P < 0.0001), and have QoL mental and physical composite scores 2.3-6.7 points lower (P < 0.0001) than patients with no/mild pruritus. Pruritus in patients undergoing HD was associated with a 23% higher mortality risk (P = 0.09). The many poor outcomes associated with pruritus underscore the need for better therapeutic agents to provide relief for the 40-50% of prevalent patients undergoing HD substantially affected by pruritus. Pruritus in new patients with end-stage renal disease likely results from uremia or pre-existing conditions (not HD per se), indicating the need to understand development of pruritus before end-stage renal disease.

Substance P and intensity of pruritus in hemodialysis and peritoneal dialysis patients

BACKGROUND

Uremic pruritus is a common complication in patients undergoing dialysis. The pathophysiological mechanisms of pruritus in patients with end-stage renal disease remain unknown. Neuropeptides, including substance P, are postulated to play an important role in the pathogenesis of pruritus. The aim of this study was to evaluate the role of substance P in uremic pruritus in patients on hemodialysis and peritoneal dialysis.

MATERIAL/METHODS

We included 197 patients with end-stage renal disease: 54 on continuous ambulatory peritoneal dialysis and 143 on hemodialysis. Substance P, calcium, phosphorus, iron, ferritin, CRP, albumin, hemoglobin, Ca×P product, and iPTH level were determined in all participants. The correlation between these parameters and self-reported itching was evaluated in patients on hemodialysis in comparison with peritoneal dialysis patients.

RESULTS

The incidence of itching was similar in hemodialysis and peritoneal dialysis patients. No differences in substance P level between the 2 groups were found. There was no correlation between substance P level and the incidence or intensity of pruritus in dialyzed patients.

CONCLUSIONS

This study demonstrates that substance P does not play any important role in pruritus in hemodialysed and peritoneal dialyzed patients. However, further studies are necessary to assess the exact role of neuropeptides in uremic pruritus.

Uremic pruritus, dialysis adequacy, and metabolic profiles in hemodialysis patients: a prospective 5-year cohort study

Background

Uremic pruritus is a common and intractable symptom in patients on chronic hemodialysis, but factors associated with the severity of pruritus remain unclear. This study aimed to explore the associations of metabolic factors and dialysis adequacy with the aggravation of pruritus.

Methods

We conducted a 5-year prospective cohort study on patients with maintenance hemodialysis. A visual analogue scale (VAS) was used to assess the intensity of pruritus. Patient demographic and clinical characteristics, laboratory parameters, dialysis adequacy (assessed by Kt/V), and pruritus intensity were recorded at baseline and follow-up. Change score analysis of the difference score of VAS between baseline and follow-up was performed using multiple linear regression models. The optimal threshold of Kt/V, which is associated with the aggravation of uremic pruritus, was determined by generalized additive models and receiver operating characteristic analysis.

Results

A total of 111 patients completed the study. Linear regression analysis showed that lower Kt/V and use of low-flux dialyzer were significantly associated with the aggravation of pruritus after adjusting for the baseline pruritus intensity and a variety of confounding factors. The optimal threshold value of Kt/V for pruritus was 1.5 suggested by both generalized additive models and receiver operating characteristic analysis.

Conclusions

Hemodialysis with the target of Kt/V ≥1.5 and use of high-flux dialyzer may reduce the intensity of pruritus in patients on chronic hemodialysis. Further clinical trials are required to determine the optimal dialysis dose and regimen for uremic pruritus.

Differences in epidermal thickness and expression of apoptosis regulatory proteins in the skin of patients with chronic renal failure and pruritus

Chronic renal failure is often associated with skin itching (pruritus) in dialysis patients. In order to investigate the possible causes of pruritus, the epidermis of the thigh of 12 dialysis patients and 4 controls from patients without renal disease were examined. The sections of the epidermis were measured and immunohistochemically analyzed using antibodies to Bcl-2, Bax, caspase-3 proteins and TUNEL method. While the mean thickness of normal epidermis was 53 μm, in dialysis patients it ranged between 23 and 34 μm during the 3-5 year period on dialysis. Compared to normal skin, the fine balance between the Bcl-2 and Bax proteins did not greatly change in the epidermis of dialysis patients during the three years of dialysis. Following five-year dialysis, the epidermis displayed increased Bax and decreased Bcl-2 expression in the basal and intermediate epidermal layers, as well as the presence of apoptotic cells (TUNEL and caspase-3 positive) both in the superficial and intermediate epidermal layers. Our study demonstrated the predominant expression of cell death Bax proteins over cell survival Bcl-2 proteins, and apoptotic cells in the deeper layers of the epidermis in patients on long-term dialysis. We speculate that the thinning of the epidermis might be associated with the appearance of dead cells in the deeper epidermal layers, while the changed internal milieu of epidermal cells could possibly affect the intra-epidermal nerve endings thus leading to the sensation of pruritus.

Efficacy of omega-3 fatty acids supplementation in treatment of uremic pruritus in hemodialysis patients: a double-blind randomized controlled trial

BACKGROUND

Uremic pruritus is a common and bothersome complaint among end-stage renal disease which affect between 25% and 60% of this population .But there is no decisive cure for treatment of it. In this study, the effects of omega-3 for treatment of pruritus were investigated in hemodialysis patients.

METHODS

A double-blind randomized study was carried out in the form of placebo-controlled crossover study in four dialysis centers in Tehran, Iran during 2008. At first, 22 hemodialysis patients suffering from pruritus with previous drug resistance were selected. Next, these patients were randomly allocated into two groups of omega-3-placebo (group A) and placebo-omega-3 (group B) .Patients in group A were treated with a 1-gram Fish oil capsule for 20 days, and subsequently, they were treated with placebo for 20 days after a 14-day wash-out period .But the reverse act was done in group B.The pruritus assessment was made quantitatively through Detailed Pruritus Score.

RESULTS

Pruritus was decreased up to 65% from score mean of 20.3 (95% CI: 16.7-23.8) to 6.4 (95% CI: 2.9-9.8) in omega-3 group and the decrease in the placebo group was 15% from score mean of 17.0 (95% CI: 12.4-21.6) to 14.4 (95% CI: 10.5-18.2).So the level of statistical difference was significant (P=0.0001).

DISCUSSION

Omega-3 fatty acids found to be more effective than placebo in decreasing of uremic pruritus. So it seems that Omega-3 fatty acids could be used as an efficient drug for treatment of pruritus in uremic patients.