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Open AccessVollständige AnalyseJun 16, 2026

Kidney-gut-skin axis in CKD-associated pruritus: mechanisms and therapeutic implications

This narrative review synthesizes mechanistic evidence on gut microbiota and the kidney-gut-skin axis in CKD-associated pruritus without providing quantifiable therapeutic efficacy data.

The question (PICO)
PopulationAdults with CKD stages 3–5 and end-stage kidney disease, including hemodialysis patients with CKD-aP
InterventionGut microbiota-directed interventions (probiotics, prebiotics, synbiotics, FMT, AST-120, phytochemicals) and kidney-gut-skin axis modulation
VergleichNot applicable (narrative review without formal comparator)
EndpunktPathophysiological mechanisms of CKD-aP; biological plausibility of microbiota-directed interventions; clinical applicability
DEvidenz
Studie
Übersichtsarbeit
Effekt
Unzureichend
Zusammenfassung der Ergebnisse nach Endpunkt
EndpunktGradRichtungEffektStudien
Prevalence of moderate-to-severe pruritus in CKDC Unzureichend24% (estudo transversal citado, sem IC 95%)1
All-cause mortality associated with severe CKD-aPC Ungünstig+17–22% (literatura citada, sem IC 95%)
Fatigue risk in CKD-aP patientsC UngünstigRR 2–5.8 (literatura citada, sem IC 95%)
Cutaneous κ-opioid receptor expression in CKD-aP vs. non-pruriticC UngünstigReduzida em HD com prurido vs. sem prurido (sem tamanho de efeito quantificado)1
Serum IL-31 levels in CKD-aPC UngünstigElevada vs. controles sem prurido (sem OR/RR/IC 95%)3
Efficacy of microbiota interventions (FMT, probiotics, AST-120) in CKD-aPD UnzureichendSem dados quantificáveis de ensaios clínicos em CKD-aP
Quality of life and sleep disturbance in CKD-aPC Ungünstig60% com insônia em CKD-aP moderado-grave (literatura citada, sem IC 95%)
Prevalence of moderate-to-severe pruritus in CKDC
Richtung Unzureichend
Effekt24% (estudo transversal citado, sem IC 95%)
Studien1
All-cause mortality associated with severe CKD-aPC
Richtung Ungünstig
Effekt+17–22% (literatura citada, sem IC 95%)
Studien
Fatigue risk in CKD-aP patientsC
Richtung Ungünstig
EffektRR 2–5.8 (literatura citada, sem IC 95%)
Studien
Cutaneous κ-opioid receptor expression in CKD-aP vs. non-pruriticC
Richtung Ungünstig
EffektReduzida em HD com prurido vs. sem prurido (sem tamanho de efeito quantificado)
Studien1
Serum IL-31 levels in CKD-aPC
Richtung Ungünstig
EffektElevada vs. controles sem prurido (sem OR/RR/IC 95%)
Studien3
Efficacy of microbiota interventions (FMT, probiotics, AST-120) in CKD-aPD
Richtung Unzureichend
EffektSem dados quantificáveis de ensaios clínicos em CKD-aP
Studien
Quality of life and sleep disturbance in CKD-aPC
Richtung Ungünstig
Effekt60% com insônia em CKD-aP moderado-grave (literatura citada, sem IC 95%)
Studien

Kontext

CKD-aP affects 18–80% of end-stage kidney disease patients and increases all-cause mortality by 17–22%. Pathophysiological mechanisms remain incompletely understood, limiting treatment. The kidney-gut-skin axis hypothesis represents a conceptual reorientation warranting investigation of microbiota-centered therapeutic targets.

Was die Studie zeigte

The study presents no original trial data or meta-analysis; it synthesizes existing literature. CKD-aP patients show elevated IL-31, IL-2, and IL-6 versus non-pruritic controls and reduced cutaneous κ-opioid receptor expression. A cited multinational cross-sectional study reported 24% prevalence of moderate-to-severe pruritus in CKD stages 3–5. Fatigue risk is 2–5.8× higher in pruritic patients; all-cause mortality elevated 17–22%. No 95% CI or effect size for microbiota interventions on pruritus outcomes is reported.

Wie es durchgeführt wurde

Structured narrative review. Databases: PubMed, Web of Science, Embase, Scopus, CNKI, and Wanfang, from inception to May 2, 2026. No PRISMA-based risk-of-bias assessment; no quantitative meta-analysis. Eligible studies included clinical, observational, interventional, review, meta-analytic, and mechanistic reports.

Effektgröße

No primary effect size calculated by the authors. Data cited from secondary literature: all-cause mortality elevated 17–22% and fatigue risk 2–5.8× higher in severe CKD-aP — no 95% CI reported in this review.

Einschränkungen

Narrative review without PRISMA protocol or risk-of-bias assessment (RoB 2, ROBINS-I, AMSTAR-2 not applied). Study selection susceptible to author confirmation bias. Mechanistic evidence predominantly from animal models and in vitro studies; generalization to human CKD-aP undemonstrated. Source population heterogeneity precludes causal conclusions. No RCT on microbiota interventions for CKD-aP is systematically evaluated.

In der klinischen Praxis

This review does NOT support practice change at evidence level A or B for any microbiota intervention in CKD-aP. Clinicians should maintain established treatments (phosphate control, skin hydration, difelikefalin where available). The kidney-gut-skin axis framework may guide hypotheses for future trials but does not alter current clinical protocols.

Was noch fehlt

Randomized controlled trials with a validated pruritus primary endpoint (WI-NRS or VAS), evaluating specific microbiota interventions (FMT, probiotics, AST-120) in confirmed CKD-aP patients, with adequate follow-up and confounder control.

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