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Abstract: FR-PO418

Psychometric Validation of the CONVINCE Inter- and Intradialytic Symptoms Questionnaire

Session Information

Category: Dialysis

  • 801 Dialysis: Hemodialysis and Frequent Dialysis

Authors

  • Pham, Le Hong Ngoc, Fresenius Medical Care Deutschland GmbH, Bad Homburg, Hessen, Germany
  • Cromm, Krister, Charite Universitatsmedizin Berlin, Berlin, Berlin, Germany
  • Zhang, Yan, Fresenius Medical Care Deutschland GmbH, Bad Homburg, Hessen, Germany
  • Schappert, Anna, Charite Universitatsmedizin Berlin, Berlin, Berlin, Germany
  • Liegl, Gregor, Charite Universitatsmedizin Berlin, Berlin, Berlin, Germany
  • Fischer, Kathrin Irmgard, Charite Universitatsmedizin Berlin, Berlin, Berlin, Germany
  • Fischer, Felix, Charite Universitatsmedizin Berlin, Berlin, Berlin, Germany
  • Rose, Matthias, Charite Universitatsmedizin Berlin, Berlin, Berlin, Germany

Group or Team Name

  • CONVINCE Scientific Committee and CONVINCE Investigators.
Background

Symptom assessment, especially from the patient perspective, is crucial in dialysis treatment. A comprehensive questionnaire is needed that covers different symptom types. In the CONVINCE study, we developed a survey based on the KDQOL symptoms scale with an adapted recall period of 7 days for interdialytic symptoms and extended inter- and intradialytic (IDS) items based on literature review and patient interviews.

Methods

Patient-reported outcomes data of 1264 hemodialysis patients were extracted from CONVINCE, an international randomized controlled trial comparing high-dose hemodiafiltration with high-flux hemodialysis, including baseline and quarterly follow-up data up to 24 months. The IDS questionnaire consists of 17 items covering interdialytic symptoms (11 based on KDQOL-36) and 5 newly developed items mainly covering intradialytic symptoms. Reliability, item, and validity analyses were conducted to assess the psychometric properties of the questionnaire. Correlations between IDS and Health-Related Quality of Life (HRQL) domains, measured with the PROMIS questionnaires, were calculated.

Results

Reliability analyses showed high internal consistency, stable over time (Cronbach’s α=.86 at baseline, .85-.90 for follow-up visits). Most item-total correlations yielded values from .37-.73, indicating good relationships between individual items and overall score. Item difficulty ranged from .14-.73, revealing a diverse range, ensuring coverage of the symptom spectrum. The survey also showed good validity as correlations between HRQL domains and IDS ranged from .36 to .61. Factor analyses identified 3 symptom clusters (Table 1).

Conclusion

The IDS questionnaire demonstrated good psychometric properties which supports its use in clinical and research settings. By providing a more comprehensive assessment, it is a useful improvement to the KDQOL symptoms scale. Symptoms identified with the questionnaire could be managed in clinical practice and help tailor individualized care.

Funding

  • Government Support – Non-U.S.