Abstract: FR-PO0404
Psychometric Validation and CAT Simulation of the Intradialytic Symptoms Questionnaire in a Multinational Hemodialysis Cohort
Session Information
- Dialysis: Measuring and Managing Symptoms and Syndromes
November 07, 2025 | Location: Exhibit Hall, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Dialysis
- 801 Dialysis: Hemodialysis and Frequent Dialysis
Authors
- Ion Titapiccolo, Jasmine, Fresenius Medical Care Italia SpA, Palazzo Pignano, Lombardia, Italy
- Bellocchio, Francesco, Fresenius Medical Care Italia SpA, Palazzo Pignano, Lombardia, Italy
- Stuard, Stefano, Fresenius Medical Care AG, Bad Homburg, HE, Germany
- Goethel-Paal, Berit, Fresenius Medical Care Deutschland GmbH, Bad Homburg, HE, Germany
- Rincon, Abraham, Fresenius Medical Care Spain, Madrid, Spain
- Baró-Salvador, Maria-Eva, Fresenius Medical Care Spain, Madrid, Spain
- Guinsburg, Adrian M., Fresenius Medical Care AG, Bad Homburg, HE, Germany
- Fazendeiro Matos, Joao, Fresenius Medical Care Portugal, Lisbon, Portugal
- Ribeiro, Ana Raquel Ferreira, Fresenius Medical Care Deutschland GmbH, Bad Homburg, HE, Germany
- Usvyat, Len A., Fresenius Medical Care Holdings Inc, Waltham, Massachusetts, United States
- Neri, Luca, Fresenius Medical Care Italia SpA, Palazzo Pignano, Lombardia, Italy
Group or Team Name
- Renal Research Institute LLC, Fresenius Medical Care.
Background
Assessment of intradialytic symptoms (IS) is vital to optimize patient comfort and outcomes, yet there is no validated intradialytic symptoms scale. We evaluated the psychometric properties and adaptive testing potential of the 12-item IS questionnaire using item-response theory (IRT) and computerized adaptive testing (CAT) simulations in a large hemodialysis population.
Methods
We extracted 15 482 adult hemodialysis (HD) surveys from centers in Czech Republic, France, Italy, Portugal, Spain, Turkey. We analyzed 1956 complete cases reporting at least one intradialytic symptom. Items were dichotomized to reflect presence versus absence of any symptom severity. A tetrachoric correlation matrix informed dimensionality assessment via principal-components analysis (PCA) and exploratory factor analysis (EFA). Internal consistency was estimated by Cronbach’s alpha. A 2PL IRT model was calibrated on a 70/30 train/test split (Ntrain = 1369; Ntest = 587), yielding item discrimination and difficulty parameters, model fit indices (AIC, BIC, RMSEA, CFI, TLI), and empirical reliability (EAP θ). CAT simulations then selected high-information items to optimize test length while preserving measurement precision.
Results
The mean inter-item tetrachoric correlation was 0.52, and PCA yielded a dominant first component (eigenvalue 6.30, 57 % variance). EFA supported a single “Systemic Symptom Load” factor explaining 53% of variance (RMSR 0.06). Internal consistency was excellent (α = 0.923; item-deleted alphas 0.908–0.924). The 2PL model demonstrated strong fit (AIC 15897; BIC 16012; RMSEA 0.059; CFI 0.976; TLI 0.970) with discrimination parameters ranging from 1.02 to 3.33 and difficulty thresholds from –2.21 to +1.72; EAP reliability was 0.815. In CAT simulations, a 7-item adaptive form correlated 0.95 with the full 12-item battery, reduced average test length by 42%, and maintained reliability ≥ 0.85 across the latent trait.
Conclusion
The IS questionnaire exhibits robust unidimensional structure and excellent IRT model fit. CAT simulations demonstrate that an adaptive IS assessment may enhance HD patient-centered monitoring, reducing respondent burden without compromising precision.
Funding
- Commercial Support – Fresenius Medical Care