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Abstract: TH-PO660

Psychometric Properties of the SF-36 Vitality Scale in Patients With Anemia of CKD

Session Information

  • Anemia and Iron Metabolism
    November 03, 2022 | Location: Exhibit Hall, Orange County Convention Center‚ West Building
    Abstract Time: 10:00 AM - 12:00 PM

Category: Anemia and Iron Metabolism

  • 200 Anemia and Iron Metabolism

Authors

  • Keeley, Tom J H, GlaxoSmithKline, Brentford, Middlesex, United Kingdom
  • Chen, Wen-Hung, GlaxoSmithKline, Collegeville, Pennsylvania, United States
  • Refoios Camejo, Rodrigo, GlaxoSmithKline, Brentford, Middlesex, United Kingdom
  • Okoro, Tony, GlaxoSmithKline, Collegeville, Pennsylvania, United States
  • Vernon, Margaret, Evidera, London, United Kingdom
  • Hsieh, Ray, Evidera, Bethesda, Maryland, United States
  • Stringer, Sonja M., Evidera, Bethesda, Maryland, United States
  • Johansen, Kirsten L., Hennepin Healthcare, University of Minnesota, Minneapolis, Minnesota, United States
Background

The Short-Form 36 is a widely used generic health-related quality of life (HRQoL) measure. The Vitality domain of the SF-36 (SF-36VT) offers a 4-item assessment of fatigue and energy levels. We evaluate the psychometric properties and score interpretation of SF-36VT in patients with anemia of chronic kidney disease (CKD).

Methods

A sample of 450 patients with anemia of CKD not currently receiving dialysis and patients initiating dialysis was used in these analyses. Assessments included reliability, construct validity and responsiveness. Thresholds for within-patient meaningful change were estimated by anchor-based (a priori anchors: Patient Global Impression of Severity [PGI-S] and PGI-Change [PGI-C]) and distribution-based methods.

Results

Internal-consistency reliability was good (Cronbach’s alpha 0.83), and test-retest reliability was acceptable (intraclass correlation coefficient 0.68). Convergent validity was strong based on correlations (≥0.5) with the Chronic Kidney Disease-Anemia Questionnaire (CKD-AQ) and the Work Productivity and Activity Impairment Questionnaire: Anemic Symptoms Clinical Practice Version (WPAI-ANS-CPV). Greater impairment based on SF-36VT score was associated with more severe ratings on PGI-S, supporting known-groups validity. SF-36VT scores were responsive to change, with consistent patterns of increase observed with improvements in other measures (eg PGI-S, SF-36 Physical Functioning, SF-36 General Health, Euroqol 5-dimension). Anchor-based methods yielded a within-patient meaningful change from Day 1 to Week 28 of 11.9 and 6.1 points on the SF-36VT based on 2-point and 1-point improvements in PGI-S, respectively. Within-patient meaningful change based on PGI-C ratings were 6.8 (very much improved) and 4.5 (moderately improved). Distribution-based estimates of within-patient meaningful change thresholds were 6.78 (0.3 SD), 11.31 (0.5 SD) and 9.56 (delta 0.50 SD).

Conclusion

SF-36VT is a reliable, construct-valid and responsive measure for assessing fatigue/energy in patients with anemia of CKD. SF-36VT within-patient meaningful change estimates help interpret the benefit of a medical intervention.

Funding

  • Commercial Support