Validation of a new instrument to measure disease‐related distress among patients with haemophilia. Issue 1 (3rd November 2020) - Kempton, Christine L.
Abstract: Introduction: In patients with haemophilia, general psychological distress as measured by the National Comprehensive Cancer Network (NCCN) distress thermometer has been associated with pain, disability and increased healthcare utilization. Aims: To develop and validate a measure of haemophilia‐related distress. Methods: After qualitative interviews, the Hemophilia‐Related Distress Questionnaire (HRDq) was developed. To validate the HRDq, adults (≥18 years) with haemophilia were enrolled, reported demographic and clinical information, and completed the HRDq and other questionnaires that measured similar constructs. Analysis included factor analysis and assessment of internal consistency using Cronbach's α, convergent validity using Pearson's correlation coefficient, and discriminant validity by comparing subgroups of patients. Test‐retest reliability was assessed using an intraclass correlation coefficient (ICC). Results: Among 130 enrolled participants, 126 (median age=32.7 years) completed the 24 item HRDq in a median time of 5.4 minutes with overall HRDq scores ranging from 2 to 83 (median score=31.5; higher scores indicating higher distress). Assessment of convergent validity demonstrated a strong correlation (ρ>.60) of the HRDq total score with the NCCN Distress Thermometer, Haem‐A‐QoL total Score, and PROMIS‐29 Profile social role domain and a mild to moderate correlation with all other questionnaire domains (.3‐.59, p < .05). Distress was higher among those who had less education, were not employed, and were disabled and was not significantly different among those with severe compared with non‐severe disease. Assessment of test‐retest reliability demonstrated an ICC value of .84 (95% CI .71‐.91) for the total score. Conclusions: The HRDq demonstrates good internal consistency, construct and discriminant validity, and retest reliability with a low responder burden.