PROMIS displays strong construct validity in pediatric and adult patients with idiopathic inflammatory myopathies

Abstract Objectives We assessed the validity of Patient-Reported Outcome Measurement Information System (PROMIS) for juvenile and adult-onset idiopathic inflammatory myopathies (JIIM/IIM) and determined associations with disease characteristics and assessments. Methods PROMIS-49 or -57 questionnaires were completed by parents (n = 70) and pediatric (n = 49) or adult patients with IIM (n = 61). Construct validity was evaluated using legacy health-related quality of life (HRQoL) instruments and associations with disease assessments and clinical characteristics. Results All groups reported decreased Physical Function (PF) (39.9–44.3, p 0.001–0.002) compared with the reference population. All groups also reported significantly increased pain interference (49.6–55.8, p 0.001), fatigue (49.5–55.1, p 0.001–0.004), and anxiety (47.0–52.5, p 0.001–0.043). PROMIS demonstrated excellent internal consistency (α 0.9) and construct validity with legacy HRQoL instruments. Parents reported worse PF (39.7 vs 42.9, p 0.001), more Fatigue (52.4 vs 48.5, p= 0.023), and higher Anxiety (49.6 vs 46.8, p= 0.032) than their children. PROMIS PF correlated best with disease activity measures (|r|=0.022–0.636), whereas Social Role, Anxiety, and Depression correlated poorly with disease activity measures. Multiple PROMIS domains correlated with Patient and Parent Global Damage, but only parent PF correlated with Physician Global Damage (|r|=0.414). Several PROMIS domains had better correlations with disease assessments than the Medical Outcomes Study Short Form-36 (SF-36). Conclusion PROMIS offers a nuanced view of HRQoL that traditional disease assessments do not adequately capture. PROMIS has good construct validity, and it may be more sensitive than legacy HRQoL measures. These findings support the incorporation of PROMIS into the assessment of IIM/JIIM to address comprehensive patient well-being.