Background:

Many patients receiving maintenance hemodialysis continue to experience persistent uremic symptoms, such as pruritus, fatigue, sleep disorders, reduced physical performance, and impaired quality of life, despite optimized dialysis prescriptions. Conventional dialysis techniques mainly rely on diffusion and convection and may be insufficient to remove certain uremic toxins, particularly protein-bound and middle-molecule solutes.

Purpose:

The ICHARUS study (Italian Cooperative HemoAdsorption Study for Relief of Uremic Symptoms) is a prospective, observational, real-world registry designed to evaluate the clinical use of hemodialysis combined with hemoadsorption (HAHD) in patients with persistent uremic symptoms.

Study design:

ICHARUS is a multicenter registry enrolling adult patients on maintenance hemodialysis in whom hemoadsorption is prescribed according to routine clinical practice. Hemoadsorption is added to standard dialysis sessions without modifying the underlying dialysis modality or prescription. The study does not involve randomization or experimental interventions.

Outcomes:

The registry will collect data on patient-reported symptoms, quality of life, selected laboratory parameters, and safety outcomes at baseline and during follow-up at 1, 3, and 6 months. The aim is to describe symptom evolution, tolerability, and real-world treatment patterns associated with HAHD.

Significance:

By collecting standardized real-world data across multiple centers, the ICHARUS registry aims to improve understanding of the potential role of hemoadsorption in chronic hemodialysis, support harmonization of clinical practice, and generate hypotheses for future interventional studies.

Rationale Despite major advances in dialysis technology, a substantial proportion of patients receiving maintenance hemodialysis continue to experience persistent uremic symptoms, including pruritus, fatigue, sleep disturbances, reduced physical performance, and impaired quality of life. Conventional dialysis modalities primarily rely on diffusive and convective solute transport and may be insufficient to remove specific classes of uremic toxins, particularly protein-bound solutes and selected middle molecules. Hemoadsorption combined with hemodialysis (HAHD) provides an additional adsorptive mechanism that may enhance the removal of these solutes and potentially contribute to symptom relief.

Study overview The ICHARUS study (Italian Cooperative HemoAdsorption Study for Relief of Uremic Symptoms) is a prospective, multicenter, observational real-world registry designed to describe the clinical use of HAHD in adult patients undergoing maintenance hemodialysis. The registry aims to collect standardized data on indications, treatment patterns, symptom evolution, and safety outcomes associated with HAHD when prescribed as part of routine clinical practice.

Study design ICHARUS is a non-interventional cohort registry. Patient enrollment is based on clinical indication for hemoadsorption, as determined by the treating physician, in the presence of persistent uremic symptoms despite optimized conventional dialysis. The decision to initiate, continue, or discontinue hemoadsorption is entirely independent of study participation and follows local clinical practice. No randomization, mandated treatment changes, or protocol-driven interventions are applied.

Treatment characteristics Hemoadsorption is performed in combination with standard hemodialysis modalities, including low-flux hemodialysis, high-flux hemodialysis, expanded hemodialysis, or hemodiafiltration, according to center expertise and patient-specific prescription. Dialysis session duration, blood and dialysate flow rates, anticoagulation strategy, and treatment frequency are not dictated by the registry and remain at the discretion of the treating team.

Data collection and follow-up Data are collected at baseline and during routine follow-up visits at approximately 1, 3, and 6 months after enrollment. Collected variables include demographic and clinical characteristics, dialysis prescription parameters, patient-reported symptoms, selected laboratory markers, and safety-related information. Follow-up assessments are aligned with standard clinical care and do not require additional procedures beyond routine practice.

Safety considerations As an observational registry, ICHARUS does not introduce experimental treatments or additional risks beyond standard clinical care. Adverse events and safety signals potentially associated with HAHD are recorded descriptively, without predefined stopping rules or intervention thresholds.

Ethical aspects The registry is conducted in accordance with the Declaration of Helsinki and applicable local regulations. Ethical approval is obtained at each participating center prior to patient enrollment. Written informed consent is collected according to local requirements.

Objectives and perspective The primary objective of the ICHARUS registry is to describe real-world patterns of HAHD use and associated changes in uremic symptoms and patient-reported outcomes over time. Secondary objectives include characterization of laboratory trends and treatment tolerability. By providing structured real-world evidence across multiple centers, the registry aims to support harmonization of clinical practice, improve patient endophenotyping, and generate hypotheses for future interventional studies.

Inclusion Criteria:

• Adult patients (≥18 years) with end-stage kidney disease (CKD stage 5D) on maintenance hemodialysis.
• Stable hemodialysis treatment for at least 3 months prior to enrollment.
• Presence of at least one moderate-to-severe uremic symptom, as identified by the Dialysis Symptom Index at screening.
• Planned treatment with hemodialysis combined with hemoadsorption according to local clinical practice.
• Ability to provide written informed consent.

Exclusion Criteria:

• Acute illness, active infection, or hospitalization within 4 weeks prior to enrollment.
• Planned kidney transplantation within the study follow-up period.
• Life expectancy less than 6 months due to non-renal comorbid conditions.
• Inability to complete patient-reported outcome questionnaires.
• Participation in another interventional clinical study that could interfere with study outcomes.

The study population consists of adult patients with end-stage kidney disease (CKD stage 5D) receiving maintenance hemodialysis in participating dialysis centers. Eligible participants are individuals with a stable dialysis regimen who report at least one clinically relevant uremic symptom at baseline, as assessed by the Dialysis Symptom Index. Patients are enrolled during routine clinical care and followed prospectively after initiation of hemodialysis combined with hemoadsorption, in accordance with local standard practice.

de-identified data, upon reasonable request, after publication

De-identified individual participant data and supporting documents will be made available beginning 6 months after publication of the primary study results and will remain available for up to 5 years thereafter.

Access to de-identified individual participant data and supporting documents will be granted to qualified researchers who submit a methodologically sound research proposal. Proposals will be reviewed by the study steering committee. Data access will require approval of the proposal and the execution of a data-sharing agreement. Data will be shared to achieve the aims of the approved proposal.