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

Comparison of effect and mechanism between nalfurafine hydrochloride and narrow-band ultraviolet B phototherapy in the treatment of pruritus in hemodialysis patients

OBJECTIVES

Pruritus in hemodialysis patients (HDP) is one of the serious complications associated with the quality of life and psychiatric disorder of patients. The narrowband ultraviolet B phototherapy (NB-UVB) treatment showed a statistically significant reduction of itching when performed more than 4 times compared to conservative treatment for itching, and the difference was confirmed to increase with repetition. We aim to compare newly developed Nalfuranfine HCL, kappa-opioid receptor agonist, with NB-UVB in HDP.

METHODS

Twenty HDP were enrolled from Wonju severance Christian hospital. Visual analog scale (VAS) score, Shiratori score, skin inflammatory cytokine levels, and blood calcium/phosphate/vitamin D levels were measured before four weeks of treatment, during four weeks of treatment, and after four weeks of treatment.

RESULTS

VAS and Shiratori score was reduced in both nalfurafine and NB-UVB treatment groups significantly. After four weeks of treatment, the NB-UVB treatment group maintained a low Shiratori score, however, the Shiratori score increased in nalfurafine treatment group. Calcium phosphate product concentration was increased in the UVB treatment group and decreased in the nalfurafine treatment group. Vitamin D level was increased only in the UVB treatment group. Skin inflammatory cytokines levels showed a decreasing trend in both groups but not statistically significant. There were no side effects in both treatment groups.

CONCLUSIONS

Nalfurafine could be an alternative treatment option compared with NB-UVB as an oral medication in pruritis in hemodialysis patients, especially those with hyperphosphatemia.

Hair Loss in a Hemodialysis Patient after Repetitive Use of the Antipruritic Drug Nalfurafine: Implications of Impaired Angiogenesis for Hair Loss

A 47-year-old man who presented with scalp hair loss was transferred to our dialysis facility 3 months after hemodialysis initiation. He noticed systemic hair loss one month after the initiation of dialysis. Because the antipruritic drug nalfurafine was the only drug that had been newly added to his regular medication after he started hemodialysis, we stopped its prescription. His hair loss was completely ameliorated for the next five months. We speculated that κ-opioid receptor activation by nalfurafine caused blood capillary regression around the hair follicles, leading to cessation of hair growth and subsequent hair fallout.

Chronic kidney disease-associated pruritus and patient-centred outcomes: a systematic review

BACKGROUND

Chronic kidney disease-associated pruritus (CKD-aP) is a debilitating symptom that can significantly impact patients' daily activities and quality of life. This systematic review aimed to assimilate the latest evidence on the relationship between CKD-associated pruritis and patient-centred outcomes.

METHODS

A comprehensive search was conducted to identify relevant studies in PubMed, Medline and Embase via OVID, CINAHL, and Web of Science from 2000 to June 2024. Quality appraisal and subsequent data extraction were performed using the Joanna Briggs Institute (JBI) tools and a modified extraction form derived from JBI.

RESULTS

The review included 29 studies with a total of 147,174 CKD patients, including those on haemodialysis (HD) and peritoneal dialysis (PD). The most frequently reported patient-centred outcomes included quality of life (n = 21), sleep quality (n = 17), anxiety/depression (n = 11) and mortality (n = 7). There was a paucity of data on patients in the pre-dialysis stages, those undergoing PD, and following a conservative (non-dialytic) pathway. The impact of CKD-associated pruritus on outcomes was contingent on the severity of CKD-associated pruritus. There was an association between increased medication usage, decreased compliance with HD treatments and higher rates of hospitalisation in patients experiencing severe pruritus.

CONCLUSION

Our review underscores the pernicious impact of CKD-associated pruritus on patient outcomes and emphasises the importance of effective management to improve patient-centred outcomes. Additional investigations are warranted among patients undergoing PD, those in pre-dialysis stages, and on conservative (non-dialytic) pathways, to achieve a more comprehensive understanding of the impact of CKD-associated pruritus in these patient groups.

Successful Use of Difelikefalin in Severe Chronic Kidney Disease-Associated Pruritus in a Patient With Complex Etiological Contributors: A Case Report

Introduction: Chronic kidney disease-associated pruritus (CKD-aP) is a frequently experienced, unpleasant skin condition. Difelikefalin, an agonist of the kappa opioid receptor, is indicated for the treatment of moderate-to-severe CKD-aP in adult patients on hemodialysis. Reports of the effectiveness of difelikefalin in complex patient cases encountered in routine clinical practice are rare. Case Presentation: The presented patient had a complex interplay of morbidities, most notably diabetes mellitus type 2, tertiary hyperparathyroidism, end-stage renal disease (ESRD), and CKD-associated mineral bone disease (CKD-MBD), all of which are associated with the development and severity of CKD-aP. The patient's CKD-aP was resistant to H1-receptor antagonists and gabapentin and showed no improvement after parathyroidectomy. Treatment with difelikefalin rapidly and sustainably improved symptoms, with a brief recurrence of itching toward the end of each long interdialytic interval. Apart from a short episode of vertigo at the initiation of treatment, no adverse events were observed over the long duration of treatment (currently more than 2.5 years). Conclusion: In a patient with longstanding conditions and multiple comorbidities, difelikefalin showed sustained effectiveness against H1-receptor antagonist- and gabapentin-resistant CKD-aP. Difelikefalin was well tolerated over the long term.

Quality of life and clinical data in hemodialysis patients with different degrees of pruritus

Chronic kidney disease-associated pruritus (CKD-aP), a persistent itching sensation, is prevalent among hemodialysis patients. This study aims to understand its prevalence, its possible association with selected solutes, and impact on quality of life (QoL) in hemodialysis patients. Involving 434 hemodialysis patients in Spain, this observational study employed a survey based on validated pruritus assessment tools, alongside demographic, clinical, and biochemical data collection. The study used statistical analyses to examine the correlation between CKD-aP and various QoL dimensions. CKD-aP affected 46,4% (202) of the participants, with no significant variation across gender and age (p = 0.222 and p = 0.379, respectively). There were no significant associations between CKD-aP and biochemical markers like calcium, phosphate, and C-reactive protein (p > 0.05, in all cases). Each reporting period (morning, midday, evening, and night) revealed distinct patterns in pruritus prevalence and severity (p < 0.05). The nighttime report exhibited the most significant differences, as more than half of the patients with moderate to severe pruritus reported constant and frequent itching (23.0% and 27.9%, respectively). Concerning other variables and symptoms associated with QoL, pruritus group exhibited higher rates of anxiety, depression, decreased sexual desire and sexual function, and sometimes to most of the time reported sleep onset problems, sleeping pill use, and drowsiness on waking (p < 0.001 in all cases). When stratifying by pruritus intensity differences persisted across anxiety (p < 0.001) and sleep onset problems (p = 0.018). The findings underscore the high prevalence and severe impact of CKD-aP in QoL among hemodialysis patients, indicating a need for standardized screening and treatment approaches in clinical practice. The lack of correlation with common biochemical markers suggests an intricate pathophysiology, warranting further investigation. These insights emphasize the necessity of holistic management strategies and more research to understand CKD-aP complex nature for better patient outcomes.

Unveiling the Burden of Pruritus: Its Prevalence and Impact on Sleep Quality in Hemodialysis Patients in Somalia

Introduction

Despite its ubiquity, pruritus is frequently underreported and inadequately handled in healthcare settings, such as Somalia. This study aimed to investigate the prevalence of pruritus and their impact on sleep quality among hemodialysis patients in Somalia.

Methods and Materials

Between February and April 2024, a cross-sectional study was done at the Mogadishu Somali Turkish Training and Research Hospital. Two hundred and ninety-nine routine hemodialysis patients had participated. The 12-item Pruritus Severity Scale (12-PSS) was used to assess pruritus severity, and the Pittsburgh Sleep Quality Index was used for sleep quality. Descriptive tests and logistic regressions were applied for analysis.

Results

The mean age of participants was 56.65 ± 12, ranging from 19 to 81 years. 76.9% of patients reported pruritus, with 68% moderate and 24.3% severe. The mean 12-PSS score was 10.32 ± 2.16. Pruritus was associated with comorbidities (OR: 2.791, P < 0.001) and duration of hemodialysis (OR: 0.609, P < 0.003). The average PSQI score was 8.69 ± 5.8, and 61.9% of patients were classified as bad sleepers. Poor sleep quality was substantially associated with pruritus (P < 0.001). We found R2 = 0.10, F (5,293) = 4.38, p < 0.001, in the multiple regression between pruritus and age, sex, duration of hemodialysis and sessions of hemodialysis per week. Also, age group, sex, presence of comorbidities, duration of hemodialysis, sessions of hemodialysis per week, and pruritus have shown R2 = 0.34, F (6,292) = 26, p < 0.001.

Conclusion

Pruritus is associated with poor sleep and patients who were living with co-morbidities and patients who were going to hemodialysis for a long time tend to develop pruritus. Effective pruritus management is critical for better patient outcomes and quality of life.

Cost effectiveness of difelikefalin for the treatment of patients with chronic kidney disease-associated pruritus undergoing hemodialysis in Italy

BACKGROUND

Chronic kidney disease (CKD)-associated pruritus is a condition that strongly impacts CKD patients and is associated with increased morbidity/mortality, and worse health-related quality of life (HRQoL). Difelikefalin is currently the only drug approved in Europe specifically for treating moderate to severe CKD-associated pruritus in patients undergoing hemodialysis. The KALM-1 and KALM-2 trials showed better efficacy of difelikefalin vs placebo and best supportive care. The aim of this study was to investigate the cost-effectiveness of difelikefalin according to the Italian National Health Service (NHS) perspective.

METHODS

A cohort model represented by four health states (No, Mild, Moderate, and Severe pruritus) was adapted to the Italian setting. The model used data from the KALM-1 and -2 trials for efficacy, integrated with other publications for HRQoL estimations. To assess the cost of disease management, a recent Italian publication on CKD-associated pruritus was used and a price of €27 per difelikefalin vial was assumed. The base case analysis over a 15-year time horizon, and an additional 10-year scenario analysis, were established. Additionally, both deterministic univariate analysis and probabilistic multivariate sensitivity analyses were developed. Discount rates of 3% were applied. An acceptability threshold of 40,000 €/quality-adjusted life-year (QALY) was considered.

RESULTS

The results show that difelikefalin plus best supportive care is cost-effective vs best supportive care alone, with an incremental cost-effectiveness ratio, in the base case, of €35,823/QALY. Both the scenario and sensitivity analyses confirmed the strength of the results.

CONCLUSIONS

Difelikefalin was found to be a cost-effective treatment for the Italian NHS. These results support its reimbursement and its inclusion in routine clinical practice.

[Pharmacological, pharmacokinetic and clinical profiles of Difelikefalin (KORSUVA® IV Injection Syringe for Dialysis), a peripheral kappa opioid receptor agonist]

Difelikefalin (KORSUVA® IV Injection Syringe for Dialysis) is a novel kappa opioid receptor (KOR) agonist. In September 2023, difelikefalin was approved for the treatment of pruritus in hemodialysis patients. Pruritus is a major symptom that significantly reduces the quality of life of hemodialysis patients, even with improved dialysis techniques, dialysis membranes, and dialysate solutions. The factors that contribute to pruritus include dry skin, accumulation of uremic toxins, overproduction of chemical mediators and altered immune function, and disruption of the opioid balance. In nonclinical studies, difelikefalin showed highly selective for KOR and antipruritic effects in animal models of histamine- and substance P-induced itching. It also showed anti-inflammatory effects by suppressing cytokine release in human monocyte-derived macrophages and TNFα and IL-1β induced by lipopolysaccharide administration in mice. In the phase 3 clinical trial in Japanese hemodialysis patients, difelikefalin showed significant improvement compared to placebo in the primary endpoint of the change from baseline in the weekly mean NRS score at week 4. It also improved sleep disturbance and itch-related quality of life, and the improvement in itch was sustained up to 58 weeks. Furthermore, there was no increase in adverse drug reactions with long-term treatment, and no delayed adverse events were observed. In conclusion, the novel KOR agonist difelikefalin is expected to be a new treatment option for pruritus on dialysis.

Burden of CKD-Associated Pruritus and Adverse Clinical Outcomes in Patients Receiving Dialysis: The Stockholm Creatinine Measurements (SCREAM) Project

RATIONALE & OBJECTIVE

Pruritus is a common but not well-characterized complaint of patients receiving maintenance dialysis. This study sought to quantify the burden of pruritus and its associated adverse health outcomes in this population.

STUDY DESIGN

Observational study.

SETTING & PARTICIPANTS

All patients receiving maintenance dialysis in Stockholm, Sweden, during 2005-2021.

EXPOSURE

Clinically recognized pruritus defined using International Classification of Diseases, Tenth Revision codes or a prescription for antipruritus treatments (including UV therapy).

OUTCOMES

All-cause mortality, severe infection-related hospitalizations (composite of endocarditis, peritoneal dialysis-related peritonitis, hemodialysis/peritoneal dialysis-related catheter infection, sepsis due to Staphylococcus spp., or skin infection) and incident diagnoses of anxiety/depression and sleep disorders.

ANALYTICAL APPROACH

Multivariable logistic regression and cause-specific hazards models to analyze factors associated with prevalent and new-onset pruritus, respectively. Multivariable cause-specific hazards models with time-varying exposure were used to explore the association of prevalent and new-onset pruritus with adverse health outcomes.

RESULTS

Among 3,281 dialysis recipients (median age, 64 years; 66% men; 69% receiving hemodialysis, 77% with incident dialysis), 456 (14%) had pruritus at enrollment. During a median follow-up of 3.3 (IQR, 1.3-9.2) years, 539 (19%) additional patients experienced pruritus. Older age, female sex, a lower serum albumin level, and higher C-reactive protein, serum calcium, and phosphorus levels were independently associated with pruritus. Compared with patients without pruritus, patients with pruritus were at a higher risk of sleep disorders (adjusted HR, 1.96; 95% CI, 1.60-2.39), developing anxiety/depression (adjusted HR, 1.56; 95% CI, 1.23-1.98), and being hospitalized for severe infections (adjusted HR, 1.36; 95% CI, 1.18-1.57), the latter attributed to higher risk of sepsis and peritoneal dialysis-related peritonitis. There was no detectable association between the development of pruritus and all-cause mortality.

LIMITATIONS

Potential misclassification bias if pruritus is not clinically recognized, lack of information on pruritus intensity/severity, use of diagnostic codes for exposure and outcome diagnoses.

CONCLUSIONS

At least one third of patients experience pruritus during their first years undergoing dialysis, and pruritus was consistently associated with adverse health outcomes.

PLAIN-LANGUAGE SUMMARY

Pruritus is a common but not well-characterized symptom of patients receiving dialysis. We analyzed data from 3,281 patients receiving maintenance hemodialysis or peritoneal dialysis in the region of Stockholm, Sweden. At baseline, 14% of patients had pruritus, and pruritus developed in an additional 19% of patients during their time receiving dialysis. We identified conditions associated with the development of pruritus (eg, older age, female sex, lower serum albumin level, and higher C-reactive protein, serum calcium, and phosphorus levels) and observed that the presence of pruritus was associated with higher risks of sleep disorders, developing anxiety and depression, and being hospitalized for severe infections. No association between pruritus and all-cause mortality was identified.

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.

Acupuncture for uremic pruritus: A systematic review and meta-analysis protocol

BACKGROUND

Uremic pruritus (UP) or chronic kidney disease-associated pruritus (CKD-aP) is one of the most intractable dermatologic symptom in patients with chronic kidney disease. Several randomized controlled trials (RCTs) have been conducted to investigate the antipruritic effects of acupuncture on UP/CKD-aP and suggested a significant therapeutic effect, while the evidence supporting the application of acupuncture is limited.

OBJECTIVES

This study will assess the efficacy and safety of acupuncture for patients with UP/CKD-aP.

METHODS

Data Sources: RCTs will be searched in MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials, Web of Science, the Chinese Biomedical Literature Database, the China National Knowledge Infrastructure, Wanfang Database, VIP Database, the WHO International Clinical Trials Registry Platform portal and www.ClinicalTrials.gov from inception to 31st August 2024. Study eligibility criteria: RCTs in English and Chinese conducted on UP/CKD-aP patients will be included. Participants: Adult patients diagnosed with UP/CKD-aP will be included. Interventions: All acupuncture interventions in the management of UP/CKD-aP will be included, compared with no treatment, placebo or sham acupuncture, or other treatment agents. Outcome measures: The primary outcome will be the change in the severity of itching evaluated by validated scales. Study appraisal and svnthesis methods: If necessary, a meta-analysis will be performed for the pooled therapeutic effect by Review Manager 5.3, or a qualitative descriptive analysis will be presented. The data will be transformed into the risk ratio (RR) for binary data and the mean difference (MD) or standardized MD for continuous data for analysis.

RESULTS

This review will update evidence of RCTs evaluating acupuncture for UP/CKD-aP.

LIMITATIONS

Anticipated challenges contain the methodological and clinical heterogeneity in terms of evaluation tools and acupuncture interventions within included studies.

CONCLUSION AND IMPLICATIONS

It will benefit patients and impact health-care decision-making regarding the models of care that are feasible for patients.

TRIAL REGISTRATION

PROSPERO CRD42021257001.

Skin barrier: new therapeutic targets for chronic kidney disease-associated pruritus - a narrative review

The current incidence of chronic kidney disease-associated pruritus (CKD-aP) in patients with end-stage renal disease (ESRD) is approximately 70%, especially in those receiving dialysis, which negatively affects their work and private lives. The CKD-aP pathogenesis remains unclear, but uremic toxin accumulation, histamine release, and opioid imbalance have been suggested to lead to CKD-aP. Current therapeutic approaches, such as opioid receptor modulators, antihistamines, and ultraviolet B irradiation, are associated with some limitations and adverse effects. The skin barrier is the first defense in preventing external injury to the body. Patients with chronic kidney disease often experience itch due to the damaged skin barrier and reduced secretion of sweat and secretion from sebaceous glands. Surprisingly, skin barrier-repairing agents repair the skin barrier and inhibit the release of inflammatory cytokines, maintain skin immunity, and ameliorate the micro-inflammatory status of afferent nerve fibers. Here, we summarize the epidemiology, pathogenesis, and treatment status of CKD-aP and explore the possibility of skin barrier repair in CKD-aP treatment.

The Pathogenesis of CKD-Associated Pruritus: A Theoretical Model and Relevance for Treatment

Our understanding of the pathogenesis of uremic pruritus (also known as CKD-associated pruritus [CKD-aP]) remains elusive. Although multiple discrete changes in the immunochemical milieu of the skin of patients with CKD-aP have been described, a coherent theory of mechanism is absent. This article proposes a theoretical model of mechanism. It concentrates on the initiation phase of CKD-aP and its three parts: ( 1 ) genesis, triggered by first precipitants; ( 2 ) cascade of cytokine release that follows and the cross-talking of multiple skin cells with each other and afferent nerve fibers; and ( 3 ) enhancement. The limitation of the model will be described and ideas for future research proposed. Implications for management shall be examined.

Impact of renal impairment on the pharmacokinetic profile of intravenous difelikefalin, a kappa opioid receptor agonist for the treatment of pruritus

BACKGROUND

Difelikefalin is a selective kappa opioid receptor agonist that is approved for the treatment of moderate-to-severe pruritus associated with chronic kidney disease in adults undergoing hemodialysis (HD). In this study, we assessed the pharmacokinetics (PK) of intravenous (IV) difelikefalin in healthy subjects, in non-dialysis-dependent (NDD) subjects with varying stages of kidney disease, and in subjects with end-stage renal disease (ESRD) undergoing HD.

METHODS

The PK and safety of single IV doses of difelikefalin (3.0 mcg/kg) were initially evaluated in NDD subjects with mild, moderate, or severe renal impairment compared with matched healthy subjects. Based on those data, the PK and safety of 3 dose levels of IV difelikefalin (0.5, 1.0, or 2.5 mcg/kg) were compared with matched placebo in subjects undergoing HD with each dose administered following dialysis, 3 times over a 1-week treatment period).

RESULTS

Single IV dosing of difelikefalin in NDD subjects (N = 36) with mild renal impairment demonstrated comparable exposure to healthy subjects with normal renal function, while subjects with moderate or severe renal impairment had higher total exposure. NDD subjects with severe renal impairment had higher total exposure compared with those with moderate renal impairment (i.e., exposure in severe NDD > moderate NDD > mild NDD ≈ healthy subjects). Clearance of difelikefalin correspondingly decreased with increasing renal impairment. In the multiple-dose study in subjects with ESRD undergoing HD (N = 19), IV difelikefalin demonstrated dose proportionality and was shown to be mostly cleared by dialysis; steady state was achieved with the second dose on day 3. Safety findings for all subjects were consistent with the known profile of IV difelikefalin.

CONCLUSIONS

IV difelikefalin was well tolerated. Similar exposure was observed in NDD subjects with mild renal impairment compared with healthy subjects with normal renal function, with reduced clearance and higher exposure in NDD subjects with moderate or severe renal impairment. Dose proportionality was demonstrated in subjects with ESRD undergoing HD administered IV difelikefalin 3 times per week following dialysis and was shown to be mostly cleared by dialysis.

TRIAL REGISTRATION

Single-dose study: NA; multiple-dose study: ClinicalTrials.gov registration number NCT02229929, first registration 03/09/2014.

Association between Chronic Kidney Disease-Mineral and Bone Disorder Biomarkers and Symptom Burden in Older Patients with Advanced Chronic Kidney Disease: Results from the EQUAL Study

Key Points

In nondialysis patients with advanced CKD, mild-to-moderately increased parathyroid hormone is associated with lower levels of reported symptoms. Phosphate and calcium are not independently associated with overall symptom burden. Patients with both severe hyperphosphatemia and severe hyperparathyroidism had the highest symptom burden.

Background

Patients with advanced CKD develop numerous symptoms, with a multifactorial origin. Evidence linking mineral disorders (CKD-Mineral and Bone Disorder) and uremic symptoms is scant and mostly limited to dialysis patients. Here, we aim to assess the association between CKD-Mineral and Bone Disorder and symptom burden in nondialysis patients with CKD.

Methods

We used data from the European Quality study, which includes patients aged ≥65 years with eGFR ≤20 ml/min per 1.73 m2 from six European countries, followed up to 5 years. We used generalized linear mixed-effect models to determine the association between repeated measurements of parathyroid hormone (PTH), phosphate, and calcium with the overall symptom number (0–33), the overall symptom severity (0–165), and the presence of 33 CKD-related symptoms. We also analyzed subgroups by sex, age, and diabetes mellitus and assessed effect mediation and joint effects between mineral biomarkers.

Results

The 1396 patients included in the study had a mean of 13±6 symptoms at baseline, with a median overall severity score of 32 (interquartile range, 19–50). The association between PTH levels and symptom burden appeared U-shaped with a lower symptom burden found for mild-to-moderately increased PTH levels. Phosphate and calcium were not independently associated with overall symptom burden. The highest symptom burden was found in patients with a combination of both severe hyperparathyroidism and severe hyperphosphatemia (+2.44 symptoms [0.50–4.38], P = 0.01). The association of both hypocalcemia and hyperphosphatemia with symptom burden seemed to differ by sex and age.

Conclusions

In older patients with advanced CKD not on dialysis, mild-to-moderately increased PTH was associated with a lower symptom burden, although the effect size was relatively small (less than one symptom). Neither phosphate nor calcium were associated with the overall symptom burden, except for the combination of severe hyperphosphatemia and severe hyperparathyroidism which was associated with an increased number of symptoms.

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.

The role of blood purification therapies in the treatment of chronic kidney disease-associated pruritus: a systematic review

Chronic kidney disease-associated pruritus (CKD-aP) is a common complication in dialysis patients which is not fully addressed by pharmacological and dialytic therapy. The objective was to review the literature on the effects of extracorporeal blood purification modalities on CKD-aP. The population comprised patients aged ≥18 years on chronic dialysis. PubMed, Embase, and Medline were systematically searched until February 2024 for clinical studies comparing the effect of different dialysis modalities on pruritus intensity. Two reviewers extracted data independently. Risk of bias for randomized controlled trials (RCTs) was assessed using the Cochrane tool. Any extracorporeal blood purification therapy for the treatment of CKD-aP was included. Outcome was quantitative change in pruritus intensity on a validated itching scale. This review included eight RCTs examining five different dialysis modalities, three observational studies examining three dialysis modalities, and six prospective clinical trials assessing four dialysis modalities. These treatments included peritoneal dialysis, low-flux and high-flux dialysis, hemodiafiltration, expanded hemodialysis, hemadsorption, hemodiafiltration with endogenous reinfusion and dialysis with polymethylmethacrylate membrane. Risk of bias was high in most studies. The largest body of evidence was found for the efficacy of hemadsorption. Limitations of evidence included heterogeneity in diagnostic tools and treatment, risk of selection bias, small sample sizes and short follow-up durations that made it challenging to perform a robust systematic review and meta-analysis. Despite the high prevalence of pruritus among dialysis patients, current evidence for efficacy of standard dialytic treatment is weak. The only technique that appears to be effective is hemoadsorption alone or coupled with hemodialysis. More high-quality studies are needed to confirm the long-term benefits.

Practical Use of Patient-Reported Outcome Measures in Chronic Kidney Disease-Associated Pruritus

Regulatory and clinical stakeholders are increasingly advocating for the use of patient-reported outcome (PRO) measures; however, the use of PROs is still not widespread. Patient reports are often the best ways to diagnose and monitor the effect of treatment on symptoms when the symptoms are subjective, as with pruritus. While many PRO tools are available to assess the severity of pruritus and its impact on quality of life (e.g., sleep), these are not used in a consistent manner and their results may not translate into clinical action. In this article, we present an introduction to PROs and their use in the assessment of chronic kidney disease-associated pruritus, as well as a practical guide to some of the PRO tools currently available, to empower all members of the nephrology patient care team to use these tools appropriately for the benefit of the patient.

Difelikefalin improves itch-related sleep disruption in patients undergoing haemodialysis

BACKGROUND

Poor sleep quality is associated with higher mortality and lower quality of life in patients with chronic kidney disease-associated pruritus (CKD-aP). Difelikefalin reduces itch in patients with CKD-aP undergoing haemodialysis (HD). This post hoc analysis of the Phase 3 difelikefalin studies (Study 3105 and the pooled dataset from KALM-1 and KALM-2) evaluated whether itch reduction in individuals with CKD-aP improved sleep quality.

METHODS

Itch intensity was assessed in patients undergoing HD who had moderate-to-severe CKD-aP treated with intravenous difelikefalin (0.5 µg/kg, three times weekly) (N = 222, Study 3105; N = 426, KALM-1 and -2) or placebo (N = 425, KALM-1 and -2) for 12 weeks, using the Worst Itch Intensity Numerical Rating Scale (WI-NRS). Sleep quality was assessed using the sleep disability question of the 5-D Itch Scale (5-D SDQ) in all studies and, in Study 3105, with the Sleep Quality Numeric Rating Scale (SQ-NRS).

RESULTS

Greater improvements in sleep quality were observed in patients with ≥3-point versus <3-point WI-NRS improvement using SQ-NRS in Study 3105 [mean (95% confidence interval) -5.2 (-5.6, -4.8) vs -1.5 (-2.0, -1.0)] and 5-D SDQ in KALM-1 and -2 [-1.8 (-2.1, -1.6) vs -0.8 (-1.1, -0.4)]. SQ-NRS and WI-NRS scores were highly correlated at both baseline and Week 12 in Study 3105 (Spearman correlation coefficient: 0.77 and 0.84, respectively). Correlations were also observed between 5-D SDQ and WI-NRS scores in Study 3105 and KALM-1 and -2.

CONCLUSIONS

In patients undergoing HD with moderate-to-severe CKD-aP, itch reduction with intravenous difelikefalin was associated with improved sleep quality. As disturbed sleep may contribute to mortality and morbidity in CKD-aP, difelikefalin may help to address a major clinical burden by improving sleep quality, secondary to itch relief.

TRIAL REGISTRATION

KALM-1 (NCT03422653), KALM-2 (NCT03636269), Study 3105 (NCT03998163).

Chronic Pruritus: A Review

Importance

Chronic pruritus, defined as itch experienced for 6 weeks or longer, affects approximately 22% of people in their lifetime. Approximately 1% of physician visits are for the chief concern of chronic pruritus. Chronic pruritus is associated with adverse outcomes, including impaired sleep and reduced quality of life.

Observations

Chronic pruritus can be categorized by etiology into inflammatory, neuropathic, or a combination of inflammatory and neuropathic pruritus. Chronic pruritus is due to inflammation in approximately 60% of patients and may be caused by eczema, psoriasis, or seborrheic dermatitis. Chronic pruritus is due to a neuropathic or mixed etiology in approximately 25% of patients. Neuropathic causes of chronic pruritus include postherpetic neuralgia and notalgia paresthetica and are typically due to localized or generalized nerve dysregulation. Approximately 15% of people with chronic pruritus have other causes including systemic diseases with secondary itch, such as uremic pruritus and cholestatic pruritus, medication-induced pruritus such as pruritus due to immunotherapy, and infectious etiologies such as tinea corporis and scabies. When few primary changes are present, a thorough history, review of symptoms, and laboratory evaluation should be performed, particularly for people with chronic pruritus lasting less than 1 year. Clinicians should consider the following tests: complete blood cell count, complete metabolic panel, and thyroid function testing to evaluate for hematologic malignancy, liver disease, kidney disease, or thyroid disease. First-line treatment for inflammatory chronic pruritus includes topical anti-inflammatory therapies such as hydrocortisone (2.5%), triamcinolone (0.1%), or tacrolimus ointment. Approximately 10% of patients do not respond to topical therapies. In these patients, referral to dermatology and systemic oral or injectable treatments such as dupilumab or methotrexate may be considered. When no underlying systemic disease associated with pruritus is identified, patients are likely to have neuropathic chronic pruritus or mixed etiology such as chronic pruritus of unknown origin. In these patients, neuropathic topical treatments such as menthol, pramoxine, or lidocaine can be used either alone or in combination with immunomodulatory agents such as topical steroids. Other effective therapies for neuropathic pruritus include gabapentin, antidepressants such as sertraline or doxepin, or opioid receptor agonist/antagonists such as naltrexone or butorphanol.

Conclusions and Relevance

Chronic pruritus can adversely affect quality of life and can be categorized into inflammatory, neuropathic, or a combined etiology. First-line therapies are topical steroids for inflammatory causes, such as hydrocortisone (2.5%) or triamcinolone (0.1%); topical neuropathic agents for neuropathic causes, such as menthol or pramoxine; and combinations of these therapies for mixed etiologies of chronic pruritus.

Comparison of the pre-dilution and post-dilution methods for online hemodiafiltration

Online hemodiafiltration (OL-HDF) is a treatment modality using diffusion and ultrafiltration. There are two types of dilution methods in OL-HDF: pre-dilution, which is commonly provided in Japan, and post-dilution, which is commonly provided in Europe. The optimal OL-HDF method for individual patients is not well studied. In this study, we compared the clinical symptoms, laboratory data, spent dialysate, and adverse events of pre- and post-dilution OL-HDF. We conducted a prospective study of 20 patients who underwent OL-HDF between January 1, 2019 and October 30, 2019. Their clinical symptoms and dialysis efficacy were evaluated. All patients underwent OL-HDF every 3 months in the following sequence: first pre-dilution, post-dilution, and second pre-dilution. We evaluated 18 patients for the clinical study and 6 for the spent dialysate study. No significant differences in spent dialysates regarding small and large solutes, blood pressure, recovery time, and clinical symptoms were observed between the pre- and post-dilution methods. However, the serum α1-microglobulin level in post-dilution OL-HDF was lower than that in pre-dilution OL-HDF (first pre-dilution: 124.8 ± 14.3 mg/L; post-dilution: 116.6 ± 13.9 mg/L; second pre-dilution: 125.8 ± 13.0 mg/L; first pre-dilution vs. post-dilution, post-dilution vs. second pre-dilution, and first pre-dilution vs. second pre-dilution: p = 0.001, p < 0.001, and p = 1.000, respectively). The most common adverse event was an increase in transmembrane pressure in the post-dilution period. Compared to pre-dilution, the post-dilution method decreased the α1-microglobulin level; however, there were no significant differences in clinical symptoms or laboratory data.

Approach using the bath preparation containing rice extract for severe pruritus in a patient receiving hemodialysis: A case report

Severe pruritus in a hemodialysis patient who had difficulty applying topical medication markedly reduced with the use of bath preparation containing rice extract. The bath preparation could be effective and an option for treating pruritus.

Prevalence, patient burden and physicians' perception of pruritus in haemodialysis patients

BACKGROUND

Chronic kidney disease-associated pruritus (CKD-aP) is an underrated symptom in patients with impaired kidney function. The present study assessed the prevalence, impact on quality of life (QoL) and risk factors for CKD-aP in a contemporary national cohort of patients on haemodialysis. In addition, we evaluated attending physicians' awareness and approach to therapy.

METHODS

Validated patient's and physician's questionnaires on pruritus severity and QoL were used in combination with information obtained by the Austrian Dialysis and Transplant Registry.

RESULTS

The prevalence of mild, moderate and severe pruritus in 962 observed patients was 34.4%, 11.4% and 4.3%. Physicians' estimated prevalence values were 25.0 (95% CI 16.8-33.2), 14.4 (11.3-17.6) and 6.3% (4.9-8.3), respectively. The estimated national prevalence estimate extrapolated from the observed patients was 45.0% (95% CI 39.5-51.2) for any, 13.9% (95% CI 10.6-17.2) for moderate and 4.2% (95% CI 2.1-6.2) for severe CKD-aP. CKD-aP severity was significantly associated with impaired QoL. Risk factors for moderate-severe pruritus were higher C-reactive protein [odds ratio (OR) 1.61 (95% CI 1.07-2.43)] and parathyroid hormone (PTH) values [OR 1.50 (95% CI 1.00-2.27)]. Therapy for CKD-aP included changes in the dialysis regimen, topical treatments, antihistamines, gabapentin and pregabalin and phototherapy in a majority of centres.

CONCLUSIONS

While the overall prevalence of CKD-aP in our study is similar to that in previously published literature, the prevalence of moderate-severe pruritus is lower. CKD-aP was associated with reduced QoL and elevated markers of inflammation and PTH. The high awareness of CKD-aP in Austrian nephrologists may explain the lower prevalence of more severe pruritus.

Pruritus and protein-bound uremic toxins in patients undergoing hemodialysis: a cross-sectional study

Background

Patients undergoing hemodialysis frequently experience pruritus; its severity is associated with poor quality of life and mortality. Recent progress in hemodialysis treatment has improved the removal of small- and middle-molecular-weight molecules; however, the removal of protein-bound uremic toxins (PBUTs) remains difficult. It is possible that pruritus is associated with serum PBUTs in patients undergoing hemodialysis.

Methods

We conducted a multicenter cross-sectional study in patients undergoing hemodialysis (n = 135). The severity of pruritus was assessed using the 5D-itch scale and medication use. Serum PBUTs, including indoxyl sulfate, p-cresyl sulfate, indole acetic acid, phenyl sulfate, and hippuric acid, were measured using mass spectrometry; the PBUT score was calculated from these toxins using principal component analysis. Univariate and multiple regression analyses were performed to examine independent predictors of pruritus.

Results

Pruritus was reported by 62.2%, 21.5%, and 13.3%, 1.5% and 0.7% as 5 (not at all), 6-10, 11-15, 16-20, and 21-25 points, respectively. The PBUT score was higher in patients undergoing dialysis having pruritus than those without pruritus (0.201 [-0.021 to 0.424] vs -0.120 [-0.326 to 0.087]; P = 0.046). The PBUT score was shown to have an association with the presence of pruritus (coefficient 0.498[Formula: see text]0.225, odds ratio: 1.65 [1.06-2.56]; P = 0.027).

Conclusion

Uremic pruritus was frequently found and associated with the PBUT score in patients undergoing hemodialysis. Further studies are required to clarify the impact of PBUTs on uremic pruritus and to explore therapeutic strategies in patients undergoing hemodialysis.

Chronic kidney disease-associated pruritus: what is known and its application in children

Chronic kidney disease-associated pruritus (CKD-aP) or uremic pruritus (UP) is a frequent symptom in patients with kidney failure receiving kidney replacement therapy. Severe chronic kidney disease-associated pruritus correlates with poor outcome in patients on dialysis. It is multifactorial in etiology and has a significant impact on quality of life. There is, however, limited data for children. This review summarizes current epidemiology, clinical characteristics, pruritus scoring systems, and available therapeutic options for pruritus in patients with chronic kidney disease and those receiving dialysis. Optimal care requires proper awareness of the severity of symptoms, the impact on quality of life, and the possible long-term outcomes. Optimizing dialysis prescription and correcting electrolyte abnormalities are important treatment targets. A wide range of therapeutic options is also available although none are well-studied in children. An earlier recognition of this debilitating symptom in children and treatment is imperative. A higher resolution version of the Graphical abstract is available as Supplementary information.

CKD-Associated Pruritus and Clinical Outcomes in Nondialysis CKD

Rationale & Objective

Itching is a frequent symptom experienced by people with chronic kidney disease (CKD). We investigated the associations of CKD-associated pruritus (CKD-aP) with clinical outcomes.

Study Design

This was a longitudinal cohort study.

Setting & Participants

Patients from Brazil, France, and the United States enrolled in the Chronic Kidney Disease Outcomes and Practice Patterns Study (CKDopps) from 2013 to 2021, an international prospective cohort study of adults with nondialysis dependent CKD, and an estimated glomerular filtration rate (eGFR) of <60 mL/min/1.73 m2 were included.

Exposure

CKD-aP was self-reported by response to the question: "During the past 4 weeks, to what extent were you bothered by itchy skin?"

Outcomes

The outcomes were as follows: CKD progression, kidney replacement therapy (KRT) initiation, mortality, hospitalization, cardiovascular events, infection events.

Analytical Approach

Associations with time-to-event outcomes were investigated using Cox proportional hazards models adjusted for potential confounders.

Results

There were 4,410 patients from 91 clinics with a median age of 69 years and a median eGFR at patient questionnaire completion of 29 (21-38) mL/min/1.73 m2. The proportion of patients not at all, somewhat, moderately, very much, and extremely bothered by itchy skin was 49%, 27%, 13%, 7%, and 3%, respectively. Patients with more advanced stages of CKD, older age, and greater comorbidities reported to be more likely bothered by itchy skin. Among patients at least moderately bothered, 23% were prescribed at least 1 pharmacotherapy (35% in the United States, 19% in France, 4% in Brazil), including antihistamine (10%), gabapentin (6%), topical corticosteroids (4%), pregabalin (3%), or sedating antihistamine (3%). The HR (95% CI) for patients extremely (vs not at all) bothered was 1.74 (1.11-2.73) for all-cause mortality, 1.56 (1.11-2.18) for all-cause hospitalization, and 1.84 (1.22-2.75) for cardiovascular events. As CKD-aP severity increased, patients also had higher rates of infection events (P = 0.04); CKD-aP severity was not associated with KRT initiation (P = 0.20) or CKD progression (P = 0.87).

Limitations

The limitations were 25% nonresponse rate, recall bias, and residual confounding factors.

Conclusions

These results demonstrate a strong association between severe itch and clinical outcomes, providing the nephrology community new insights into the possible adverse consequences of CKD-aP in individuals with nondialysis CKD, and warrant further exploration.

Plain-Language Summary

Chronic kidney disease-associated pruritus (CKD-aP) is a common disturbing symptom of chronic kidney disease (CKD). This article analyzes longitudinal data from the Chronic Kidney Disease Outcomes and Practice Patterns Study (CKDopps) to describe prevalence of CKD-aP in 4,410 individuals with nondialysis CKD, and its association with clinical outcomes. We found that 51% of the surveyed population were bothered by pruritus. CKD-aP was more prevalent in those with more advanced stages of CKD, older age, and with more comorbid conditions. Compared to those not at all bothered by pruritus, those who were extremely bothered had a higher risk of all-cause mortality, hospitalizations, and cardiovascular events. Severity of CKD-aP was not associated with CKD progression or initiation of kidney replacement therapy.

Pruritus in Hemodialysis Patients: Longitudinal Associations With Clinical and Patient-Reported Outcomes

RATIONALE & OBJECTIVE

Cross-sectional studies have reported an association of chronic kidney disease-associated pruritus (CKD-aP) with adverse clinical events and patient-reported outcomes (PROs). We studied the longitudinal associations between changes in CKD-aP and clinical outcomes among patients receiving maintenance hemodialysis.

STUDY DESIGN

Prospective cohort study.

SETTING & PARTICIPANTS

7,976 hemodialysis recipients across 21 countries in phases 4-6 (2009-2018) of the Dialysis Outcomes and Practice Patterns Study (DOPPS) who had 2 CKD-aP assessments approximately 12 months apart.

EXPOSURES

Exposure status was based on the assessment of pruritis initially and again approximately 1 year later. Four groups were identified, including those with moderate or more severe pruritis only at the initial assessment (resolved), only at the second assessment (incident), at neither assessment (absent), or at both assessments (persistent).

OUTCOMES

Laboratory values and PROs ascertained at the initial assessment of pruritis and 1 year later.

ANALYTICAL APPROACH

Linear mixed model to investigate changes in laboratory values and PROs over the 1-year study period across the 4 exposure groups.

RESULTS

51% of patients had moderate to severe CKD-aP symptoms at either assessment (22% at both). The prevalences of depression, restless sleep, and feeling drained increased over the study period (+13%,+10%, and+14%, respectively) among patients with incident pruritus and decreased (-5%, -8%, and -12%, respectively) among patients with resolved pruritus. Minimal changes in PROs over time were observed for the absent and persistent groups. Changes over time in laboratory values (phosphorus, Kt/V) were not detected for either of these groups. Compared with patients with absent CKD-aP, the adjusted HRs for patients with persistent CKD-aP were 1.29 (95% CI, 1.09-1.53) for all-cause mortality, 1.17 (1.07-1.28) for all-cause hospitalization, and 1.48 (1.26-1.74) for cardiovascular events.

LIMITATIONS

No interim evaluation of CKD-aP symptoms between the 2 assessments; potential selection bias from patients who died or were otherwise lost to follow-up before the second assessment.

CONCLUSIONS

CKD-aP symptoms are chronic, and these findings highlight the potential value of repeated assessment of this symptom using standardized approaches. Future research should systematically investigate potential causes of CKD-aP and options for its effective treatment.

PLAIN-LANGUAGE SUMMARY

Previous research has studied itching and its consequences in hemodialysis recipients only at a single time point. We surveyed 7,976 patients receiving maintenance hemodialysis to assess itching over a period of 1 year. We found that, among those experiencing itching at the initial assessment, more than half had persistent symptoms 1 year later. Those in whom itching developed during follow-up were more likely to experience depression, poor sleep, long recovery times after dialysis, and feeling faint or drained. These patients also rated their quality of life as poorer than those who did not experience itching. These findings emphasize the potential value of clinical detection of itching and the pursuit of effective treatments for patients receiving dialysis experiencing these symptoms.

Randomized controlled trial of nalfurafine for refractory pruritus in hemodialysis patients

Background: Chronic kidney disease-associated pruritus (CKD-aP) is very common and sometimes refractory to treatment in hemodialysis patients. In a trial conducted in Japan, nalfurafine, effectively reduced itching of treatment-resistant CKD-aP. Our present bridging study aimed to evaluate the efficacy and safety of nalfurafine in Chinese cohort with refractory CKD-aP.Methods: In this phase III, multicenter bridging study conducted at 22 sites in China, 141 Chinese cases with refractory CKD-aP were randomly (2:2:1) assigned to receive 5 μg, 2.5 μg of nalfurafine or a placebo orally for 14 days in a double-blind manner. The primary end point was the mean decrease in the mean visual analogue scale (VAS) from baseline.Results: A total of 141 patients were included. The primary endpoint analysis based on full analysis set (FAS), the difference of mean VAS decrease between 5 μg nalfurafine and placebo group was 11.37 mm (p = .041); the difference of mean VAS decrease between 2.5 μg and placebo group was 8.81 mm, but not statistically significantly different. Both differences were greater than 4.13 mm, which met its predefined success criterion of at least 50% efficacy of the key Japanese clinical trial. The per protocol set (PPS) analysis got similar results. The incidence of adverse drug reactions (ADRs) was 49.1% in 5μg, 38.6% in 2.5 μg and 33.3% in placebo group. The most common ADR was insomnia, seen in 21 of the 114 nalfurafine patients.Conclusions: Oral nalfurafine effectively reduced itching with few significant ADRs in Chinese hemodialysis patients with refractory pruritus.

Uremic pruritus: prevalence, determinants, and its impact on health-related quality of life and sleep in Indian patients undergoing hemodialysis

BACKGROUND

Uremic pruritus has an impact on the quality of life and sleep of hemodialysis patients, but the majority of cases go unreported and untreated unless severe, due to a lack of awareness. The purpose of this study is to determine the prevalence, associated factors, and impact on health-related quality of life (HR-QOL) and sleep in hemodialysis patients.

METHODOLOGY

A single-center observational study of 3 months wherein 120 adults on maintenance hemodialysis were included. Baseline characteristics, dialysis-related factors, and lab parameters influencing uremic pruritus were recorded. Those with uremic pruritus completed "12-item pruritus severity scale (12-PSS)", "SKINDEX10", and "Itch-MOS" questionnaires to evaluate severity, impact on HR-QOL, and sleep respectively.

RESULTS

Sixty seven over one hundred twenty (55.83%) patients had pruritus and majority were mild (40.83%) as per 12-PSS. Those with pruritus (n=67) had a mean age of 56.5±11.3 years, most were males (82%), chronic glomerulonephritis (29.1%) was the commonest cause of end-stage kidney disease, 3 active smokers, and 4 seropositive. 65(97%) patients were on twice-weekly dialysis, 36/67 had <5 years' dialysis vintage and acceptable adequacy. There was no significant association between uremic pruritus and dialysis-related/laboratory parameters. Patients with uremic pruritus demonstrated significantly worse "HR-QOL" (p<0.001) on the "SKINDEX-10", and patients' "Itch-MOS" scores demonstrated a significant decline in sleep quality with increasing pruritus severity (p<0.001).

CONCLUSION

The majority of patients on maintenance hemodialysis experience uremic pruritus. None of the clinical characteristics, dialysis-related factors, and laboratory parameters affected uremic pruritus. Uremic pruritus patients had the worst HR-QOL & their sleep quality significantly declined as pruritus severity escalated.

TRIAL REGISTRATION NUMBER AND DATE OF REGISTRATION

Study approval was obtained from Institutional Research Committee and Institutional Ethical Committee (IEC 642/2021). Clinical Trial Registry of India (CTRI) registration (CTRI/2022/01/039143) was also obtained.

Difelikefalin for Hemodialysis Patients with Pruritus in Japan

BACKGROUND: Difelikefalin, a peripherally specific selective agonist of kappa opioid receptors, has been approved for the treatment of pruritus in hemodialysis patients in the United States. However, there is limited evidence for postdialysis intravenous use in non-U.S. populations. METHODS: In this double-blind, placebo-controlled, phase 3 trial in Japan, patients with moderate to severe pruritus were randomly allocated 1:1 to receive either placebo or 0.5 μg/kg of difelikefalin three times per week intravenously for 6 weeks. The primary end point was change from baseline in the Worst Itching Intensity Numerical Rating Scale (NRS; 0 to 10; higher scores indicate more severe itching) score at week 4. RESULTS: A total of 230 patients were screened, of whom 178 were randomly assigned to receive placebo (n=89) or difelikefalin (n=89). The change from baseline in the weekly adjusted mean NRS score (95% confidence interval) at week 4 in the placebo and difelikefalin groups was −1.09 (−1.47 to −0.70) and −2.06 (−2.45 to −1.66), respectively. The difference between the groups was −0.97 (−1.52 to −0.42), demonstrating that difelikefalin was superior to placebo (P<0.001). Prespecified secondary quality-of-life end points showed consistent improvement associated with difelikefalin. The incidence of treatment-related adverse events in the placebo and difelikefalin groups was 3 of 89 patients (3%) and 13 of 89 patients (15%), respectively, of which the majority in the difelikefalin group were gastrointestinal (e.g., constipation and abdominal discomfort). CONCLUSIONS: Intravenous difelikefalin reduced itching and improved quality of life in patients with moderate to severe pruritus who were undergoing maintenance hemodialysis. (Funded by Kissei Pharmaceutical Co., Ltd.; ClinicalTrials.gov number, NCT04711603.)

Chronic kidney disease-associated pruritus (CKD-aP) is associated with worse quality of life and increased healthcare utilization among dialysis patients

PURPOSE

Chronic pruritus significantly impairs hemodialysis patients' health status and quality of life (QOL) and it is associated with higher mortality rate, more frequent hospitalizations, poorer dialysis and medication adherence, and deteriorated mental status. However, pruritus is still underestimated, underdiagnosed, and undertreated in the real-life clinical scenario. We investigated prevalence, clinical characteristics, clinical correlates, severity as well as physical and psychological burden of chronic pruritus among adult hemodialysis patients in a large international real-world cohort.

METHODS

We conducted a retrospective cross-sectional study of patients registered in 152 Fresenius Medical Care (FMC) NephroCare clinics located in Italy, France, Ireland, United Kingdom, and Spain. Demographic and medical data were retrieved from the EuCliD® (European Clinical) database, while information on pruritus and QoL were abstracted from KDQOL™-36 and 5-D Itch questionnaire scores.

RESULTS

A total of 6221 patients were included, of which 1238 were from France, 163 Ireland, 1469 Italy, 2633 Spain, and 718 UK. The prevalence of mild-to-severe pruritus was 47.9% (n = 2977 patients). Increased pruritus severity was associated with increased use of antidepressants, antihistamines, and gabapentin. Patients with severe pruritus more likely suffered from diabetes, more frequently missed dialysis sessions, and underwent more hospitalizations due to infections. Both mental and physical QOL scores were progressively lower as the severity of pruritus increased; this association was robust to adjustment for potential confounders.

CONCLUSION

This international real-world analysis confirms that chronic pruritus is a highly prevalent condition among dialysis patients and highlights its considerable burden on several dimensions of patients' life.

The Burden of Pruritus Associated With CKD: A Mixed Methods Analysis Among Patients Undergoing Dialysis

Rationale & Objective

Despite its prevalence and distress to patients, chronic kidney disease-associated pruritus (CKD-aP) is poorly characterized, which may contribute to the condition's underdiagnosis and inadequate management. This study aimed to understand the symptom experience of patients with CKD-aP and the extent to which pruritus impacts their lives.

Study Design

Mixed methods study including one-on-one qualitative interviews and completion of the Skindex-10 Questionnaire (measuring itch-related quality of life).

Setting & Participants

A total of 23 patients undergoing hemodialysis and reporting pruritus at 4 dialysis centers in the United States.

Analytical Approach

Interviews followed a semistructured guide that included targeted and follow-up questions to elicit discussion of patients' symptoms of pruritus, including frequency and variability, impact on activities of daily living, and emotional and social functioning. Interviews were digitally audio-recorded. A coding dictionary was developed from transcripts to analyze themes and concepts.

Results

Participants described their itch with various terms, including "numbness," "pain," and "tingling" on their skin. Itch affected multiple areas but especially the back, usually occurred daily, and was often worse at night. For some, itching was a constant experience. Patients relieved their itch through scratching and various off-label treatments; some reported skin damage from excessive scratching and most indicated treatments provided limited relief. Pruritus considerably disrupted physical function, including sleep, daily activities, social functioning and relationships, and emotional and psychological wellbeing. All participants reported being bothered by their itching during the past week on the Skindex-10 Questionnaire.

Limitations

All participants were from the United States, so the findings may not be generalizable to other countries.

Conclusions

Although symptom experience varies considerably, CKD-aP causes severe distress for many patients undergoing hemodialysis and can profoundly impair their quality of life. The results of this study show the impact of itch from patients' perspectives and highlight the need for greater awareness and better management of this condition.

Plain-Language Summary

Patients with chronic kidney disease often experience itching, or pruritus, but its importance to patients is regularly overlooked. This study used one-on-one interviews to investigate patients' experiences of chronic kidney disease-associated pruritus and how it impacts their lives. We found that participants experienced itch on various body areas and used different words to describe their itch (eg, "numbness" and "pain"). Some reported skin damage from excessive scratching, and many used off-label treatments and other interventions (eg, rubbing alcohol and multiple showers daily), which provided limited relief. For many, itching was experienced daily and severely disrupted sleep, daily activities, interactions with others, and mental wellbeing. These findings reveal chronic kidney disease-associated pruritus severely impacts patients and highlights the need for improved management of this condition.

[Management of pruritus in the elderly]

BACKGROUND

Chronic pruritus (CP), a frequent (20.3%) symptom in the elderly, increases with age. It has a significant impact on the quality of life, ranking among the 50 most burdensome diseases worldwide (Global Burden of Disease Study).

OBJECTIVES

The aim is to provide an overview of the symptom CP in the elderly and to improve differentiation of underlying conditions and management of this entity.

MATERIALS AND METHODS

A literature search in PubMed was performed, using the terms 'pruritus', 'elderly' and 'gerontodermatology'.

RESULTS

The main causes of CP in the elderly are the physiologic aging process (xerosis cutis, immunosenescence, neuropathy), the increase in potentially pruritic diseases with increasing age (diabetes mellitus, chronic renal failure), and polypharmacy. Therapeutic options relate to causes, severity of pruritus, and individual patient factors (multimorbidity, impaired organ function). The recently updated S2k guideline 'Diagnosis and therapy of chronic pruritus' is helpful.

CONCLUSION

CP in the elderly is challenging for both patients and physicians. Not only the difficulty of identifying the underlying cause, but the complexity of treatment and its tolerability and practicability determines these patients' further burden.

Pharmacokinetics, Metabolism, and Excretion of Intravenous [14C]Difelikefalin in Healthy Subjects and Subjects on Hemodialysis

BACKGROUND AND OBJECTIVE

Difelikefalin, a selective kappa-opioid receptor agonist, is the first approved treatment for moderate-to-severe pruritus in patients with end-stage renal disease (ESRD) on hemodialysis (HD) in the USA and Europe. The purpose of this open-label study was to investigate the pharmacokinetics and disposition of [14C]difelikefalin following a single intravenous dose in subjects with normal renal function and subjects on HD.

METHODS

Twelve adult males (n = 6 healthy subjects; n = 6 subjects on HD) received single intravenous doses of [14C]difelikefalin containing 100 µCi (total doses of 1.7-3.0 μg/kg difelikefalin). Blood, urine, feces, and dialysate samples (when applicable) were collected after dosing.

RESULTS

The median time to maximum concentration was similar for HD and healthy subjects, occurring at 5 min post-dose. The mean area under the concentration-time curve (AUC) was approximately 11-fold higher in HD versus healthy subjects; mean plasma half-life was 38.0 h and 2.6 h, respectively. In healthy subjects, 80.5% of the dose was recovered in urine, and 11.3% was recovered in feces. In subjects on HD, 58.8% of the dose was recovered in feces, and 19.5% was recovered in dialysate [for subjects on HD with residual kidney function (n = 3), 11.2% was recovered in urine]. Based on plasma AUClast, parent [14C]difelikefalin was the most abundant analyte in systemic circulation (> 99% of total exposure) for both cohorts. Metabolite profiles in urine and feces suggested minimal metabolism of the parent compound.

CONCLUSION

In subjects on HD, difelikefalin total exposure was higher and plasma half-life was longer compared with subjects with intact renal function. Metabolism was low in both healthy subjects and subjects on HD, with unchanged drug representing > 99% of systemic circulation; however, the route of excretion was primarily into urine versus feces in healthy subjects, and feces versus dialysate in subjects on HD.

REGISTRATION

ClinicalTrials.gov NCT03947970.

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.

[Translated article] Pruritus in Dermatology: Part 2-Diseases and Their Treatment

Pruritus is the main symptom of many dermatologic and systemic diseases. Atopic dermatitis, psoriasis, contact dermatitis, urticaria, lichen simplex chronicus, mycosis fungoides, scars, autoimmune diseases, kidney or liver diseases among others are all associated with itch that may require different approaches to management. Although antihistamines seem to be the first line of therapy, in reality their role is limited to urticaria and drug-induced reactions. In fact, the pathophysiologic mechanisms of each of the conditions covered in this review will differ. Recent years have seen the emergence of new drugs whose efficacy and safety profiles are very attractive for the management of pruritus in clinical practice. Clearly, we are at a critical moment in dermatology, in which we have the chance to be more ambitious in our goals when treating patients with pruritus.

Serum Level of Protein-Bound Uraemic Toxins in Haemodialysis Patients with Chronic Kidney Disease-Associated Pruritus: Myths and Facts

Recent studies place great importance on Protein-Bound Uraemic Toxins (PBUT) in the context of etiopathogenesis of chronic kidney disease-associated pruritus (CKD-aP). This study aimed to investigate the possible contribution of free and total Indoxyl Sulfate (IS) and p-Cresol Sulfate (PCS) to the cause of CKD-aP. Group A included 64 patients on maintenance haemodialysis (HD) with CKD-aP. Group B included 62 patients on maintenance HD that did not report CKD-aP, and group C included 50 healthy controls. Pruritus severity was assessed using a Numerical Rating Scale (NRS). Moreover, other tools like UP-Dial, ItchyQoL, and the 4-Item Itch Questionnaire evaluating CKD-aP were completed by the patients. The serum levels of free and total IS and PCS concentrations were measured using the Ultra Performance Liquid Chromatography System. No significant difference in the serum level of free and total IS, or PCS, was observed between the patients who reported CKD-aP and those without pruritus. Moreover, there was no correlation between serum IS or PCS levels and the severity of the itch. Our study does not support earlier findings about higher levels of IS and PCS in patients reporting CKD-aP. Further studies will be needed to investigate these discrepancies as well as to understand the cause of CKD-aP.

Incidence and Risk Factors for Pruritus in Patients with Nondialysis CKD

BACKGROUND

Pruritus is a common symptom experienced by patients with nondialysis CKD, but risk factors for incident pruritus in this patient population have not been evaluated.

METHODS

We identified 1951 participants with CKD in the Chronic Renal Insufficiency Cohort Study without pruritus at the baseline assessment. Pruritus was assessed by the Kidney Disease Quality of Life-36 (KDQOL-36) instrument, and moderate-to-severe pruritus was defined as a response of 3 or higher on a Likert scale of 1-5. We used time-updated multivariable joint models to evaluate the association of patient clinical characteristics, eGFR, and laboratory parameters with incident pruritus.

RESULTS

Over a median follow-up of 6 years, 660 (34%) participants developed incident moderate-to-severe pruritus, with a higher incidence rate observed among participants with more advanced CKD. In multivariable models, the hazard ratio (95% confidence interval [CI]) for pruritus associated with a 10 ml/min per 1.73 m 2 lower eGFR was 1.16 (95% CI, 1.10 to 1.23). Older age (≥65 years), higher body mass index, diabetes, current smoking, opioid use, depressive symptoms, and serum parathyroid hormone were also associated with a higher risk of incident pruritus, whereas low serum calcium (<9 mg/dl) was associated with a lower risk (all P <0.05). Serum phosphate was not associated with incident pruritus in the primary analysis.

CONCLUSIONS

A substantial proportion of patients with nondialysis CKD develop moderate-to-severe pruritus. Although lower eGFR is associated with the risk of pruritus, other comorbidities, particularly depressive symptoms, were potential risk factors.

PODCAST

This article contains a podcast at https://www.asn-online.org/media/podcast/CJASN/2023_02_08_CJN09480822.mp3.

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.

Perception of Spanish nephrologists on an old unsolved problem: Pruritus associated with chronic kidney disease (CKD-aP)

INTRODUCTION

Pruritus associated with chronic kidney disease is defined as the sensation of itching, in people with chronic kidney disease, in a one area or all over the body that causes the need to scratch, after having ruled out other dermatological or systemic causes. It is an old and known problem whose prevalence has been able to decrease with the improvement of dialytic techniques but which still persists and is underdiagnosed.

OBJECTIVES

The objective of this study was to analyse the current perception of nephrologists about this problem that influences the quality of life of people with chronic kidney disease through a survey.

RESULTS

135 nephrologists, most of them engaged in haemodialysis, participated. 86% considered that pruritus associated with chronic kidney disease is still a problem today that affects the quality of life. Most nephrologists believe that the main pathophysiological cause is uremic toxins (60%) and only 16% believe that it is due to the dysregulation of the opioid system/endorphins-dynorphins. Only 16% comment that the prevalence of pruritus in their centre is greater than 20%. 40% believe that the diagnosis is made because it is manifested by the patient and only 27% because it is asked by the doctor. Moreover, it is not usual to use scales to measure it or the codification in the medical records. The main treatment used is antihistamines (96%), followed by moisturizers/anaesthetics (93%) and modification of the dialysis regimen (70%).

CONCLUSIONS

Pruritus associated with chronic kidney disease is still a current problem, it is underdiagnosed, not codified and with a lack of indicated, effective and safe treatments. Nephrologists do not know its real prevalence and the different pathophysiological mechanisms involved in its development. Many therapeutic options are used with very variable results, ignoring their efficacy and applicability at the present time. The new emerging kappa-opioid-receptor agonist agents offer us an opportunity to reevaluate this age-old problem and improve the quality of life for our patients with chronic kidney disease.

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.

Prevalence and determinants of severity of uremic pruritus in hemodialysis patients: a multicentric study

Uremic pruritus (UP) is a common and distressing symptom in patients with advanced or end-stage renal disease under hemodialysis (HD). The present multicentric study aimed to identify prevalence and determinants of severity of UP among Egyptian patients. Performed investigations included serum urea, creatinine, calcium, phosphorus, parathormone, ferritin and liver enzymes. Pruritus was evaluated using the visual analog scale. The study included 295 patients on maintenance HD. They comprised 151 patients (51.2%) with UP. Independent predictors of UP included associated hypertension (OR: 0.48, 95% CI 0.28 to 0.83, p=0.008), higher calcium levels (OR: 1.29, 95% CI 1.02 to 1.62, p=0.032), higher phosphorus levels (OR: 1.18, 95% CI 1.02 to 1.37, p=0.03) and higher high-sensitivity C-reactive protein (hsCRP) levels (OR: 1.0, 95% CI 1.0 to 1.01, p=0.049). Independent predictors of significant UP included longer HD duration (OR: 1.23, 95% CI 1.1 to 1.38, p<0.001), lack of vitamin D supplementation (OR: 3.71, 95% CI 1.03 to 13.4, p=0.045), lower albumin levels (OR: 0.32, 95% CI 0.14 to 0.74, p=0.008) and higher hsCRP levels (OR (CRP): 1.02 (1.0-1.03), p=0.011). In conclusion, UP is fairly common among Egyptian HD patients. Independent predictors of UP severity include longer HD duration, lack of vitamin D supplementation, lower albumin levels and higher hsCRP levels.

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.

Acupuncture for Uremic Pruritus: A Systematic Review and Meta-Analysis

Uremic pruritus (UP) is a chronic disease that can seriously affect the quality of life of dialysis patients. Acupuncture is a non-medication therapy that has been used to treat pruritus disorders. This systematic review aimed to evaluate the efficacy and safety of acupuncture for the treatment of UP. A total of nine Chinese and English databases were searched from their inception to December 31, 2021, and 214 studies were retrieved. Finally, seven randomized controlled trials (n=504) were included in the meta-analysis performed using RevMan V.5.3. Results included effective rate, recurrence rates, and adverse events. Compared with conventional treatment, acupuncture was more effective in treating UP (risk ratio [RR]=1.28, 95% confidence interval [CI]=1.09 to 1.50, P=0.003). The results were consistent after sensitivity analysis (RR=1.38, 95% CI=1.21 to 1.57, P<0.00001). In subgroup analysis, the efficacy rates of acupuncture and medications (oral and topical) were comparable (RR=1.20, 95% CI=0.98 to 1.47, P=0.07). Acupuncture combined with hemodialysis was more effective than hemodialysis alone in relieving pruritus (RR=1.42, 95% CI=1.18 to 1.72, P=0.0002). Adverse events were reported in only three studies, including one case of hyperphosphatemia in the medications group (RR=0.29, 95% CI=0.01 to 7.06, P=0.45). None of the studies reported recurrence rates. In conclusion, acupuncture is a safe treatment modality for patients with UP receiving hemodialysis that can effectively improve UP symptoms, and acupuncture in combination with hemodialysis has more efficacy than hemodialysis alone in improving the UP symptoms.