Liegl, Gregor, Fischer, Felix H., Canaud, Bernard, Woodward, Mark, Barth, Claudia, Davenport, Andrew, Török, Marietta, Strippoli, Giovanni F. M., Hegbrant, Jörgen, Cromm, Krister, Bots, Michiel L., Blankestijn, Peter J., Fischer, Kathrin I., and Rose, Matthias
Purpose: We applied a previously established common T-score metric for patient-reported and performance-based physical function (PF), offering the unique opportunity to directly compare measurement type-specific patterns of associations with potential laboratory-based, psychosocial, sociodemographic, and health-related determinants in hemodialysis patients. Methods: We analyzed baseline data from the CONVINCE trial (N = 1,360), a multinational randomized controlled trial comparing high-flux hemodialysis with high-dose hemodiafiltration. To explore the associations of potential determinants with performance-based versus patient-reported PF, we conducted multiple linear regression (backward elimination with cross-validation and Lasso regression). We used standardized T-scores as estimated from the PROMIS PF short-form 4a (patient-reported PF) and the Physical Performance Test (performance-based PF) as dependent variables. Results: Performance-based and patient-reported PF were both significantly associated with a laboratory marker-based indicator of muscle mass (simplified creatinine index), although the effects were relatively small (partial f2 = 0.04). Age was negatively associated with PF; the effect size was larger for performance-based (partial f2 = 0.12) than for patient-reported PF (partial f2 = 0.08). Compared to performance-based PF, patient-reported PF showed a stronger association with self-reported health domains, particularly pain interference and fatigue. When using the individual difference between patient-reported and performance-based T-scores as outcome, we found that younger age and more fatigue were associated with lower patient-reported PF compared to performance-based PF (small effect size). Conclusion: Patient-reported and performance-based assessments were similarly associated with an objective marker of physical impairment in hemodialysis patients. Age and fatigue may result in discrepancies when comparing performance-based and patient-reported scores on the common PF scale. Trial Registration CONVINCE is registered in the Dutch Trial Register (Register ID: NL64750.041.18). The registration can be accessed at: https://onderzoekmetmensen.nl/en/trial/52958. [ABSTRACT FROM AUTHOR]