The use of PROMIS patient-reported outcomes (PROs) to inform light chain (AL) amyloid disease severity at diagnosis

We sought to evaluate how PROMIS patient-reported outcome (PRO) measures correlated with disease characteristics in systemic light chain (AL) amyloidosis patients at diagnosis. Newly diagnosed AL patients were recruited at two centres (N = 61). Patients completed the PROMIS Global Health v1.2, PROMIS-29 Profile v2.0 and Fatigue 8a v1.0. We assigned disease severity based on stage, presence of cardiac AL, and number of organs involved. We evaluated a) known groups validity by comparing PROMIS T-scores by disease severity, b) internal consistency using Cronbach's alpha and c) convergent/discriminant validity based on correlations across the domains and summary scores. Using receiver operating characteristic (ROC) curve analysis, NT-proBNP cut-off level corresponding to normal/mild vs moderate/severe PRO scores was determined. The median age was 68 (48-83) years with 58% males. Sixty-six percent had cardiac involvement and 25% had 3 or more organs involved with AL amyloidosis; 14% had stage 1, 28% stage 2, 36% stage 3 and 16% stage 4 disease. PROMIS measures had acceptable to excellent internal consistency and expected patterns of correlations. PROMIS Global Physical Health score was worse than the Global Mental Health Score at diagnosis; Physical function, fatigue and anxiety were the most impaired domains. PROMIS Global Health summary scores discriminated across AL amyloidosis stage and number of organs involved. Physical Function showed the strongest effects across known groups by stage, cardiac involvement and number of organs involved followed by Ability to Participate in Social Roles and Activities. A diagnostic NT-proBNP cut-off of 4200 pg/ml identified patients with moderate/severe PRO scores for these domains. Our results provide evidence for reliability and validity of select PROMIS short form measures in AL amyloidosis at diagnosis.