Development and initial validation of the AL-PROfile patient-reported outcome measure in light chain (AL) amyloidosis

Objective: To evaluate the psychometric properties of the AL-PROfile, a patient-reported outcome measure combining the Patient-Reported Outcomes Measurement Information System (PROMIS)-29, two items from PROMIS Cognitive Function, and select Patient-Reported Outcomes version of the Common Terminology Criteria for Adverse Events (PRO-CTCAE) items. Methods: Content validity was assessed through cognitive debriefing interviews of 20 patients who completed the AL-PROfile (Study 1). Study 2 involved 297 participants who completed the AL-PROfile and Medical Outcomes Study 36-item Short-Form Health Survey (SF-36). Reliability (internal consistency and test-retest reliability) and validity (convergent and discriminant validity, known groups validity by stage/organ involvement) were calculated. Results: Study 1 participants found the AL-PROfile straightforward confirming the relevance of the included content. Some felt that certain questions were not related to their amyloidosis experience. Study 2 demonstrated acceptable internal consistency for all domains/items except PROMIS Cognitive Function and acceptable test-retest reliability for all except PROMIS Cognitive Function and PRO-CTCAE nausea. Large correlations were seen for the same domain across measures while correlations for divergent domains within a measure and different domains across different measures were small. The PRO-CTCAE items showed small to medium correlations with each other and with PROMIS and SF-36 domains. Stage was associated with physical function, fatigue, social roles, swelling, and shortness of breath scores. Conclusion: The AL-PROfile has acceptable reliability and validity for use in systemic light chain amyloidosis patients.