Development and initial validation of a brief measure of uncertainty in rheumatic disease

Patients with rheumatic diseases face uncertainty which is associated with decreased well-being. Current abbreviated uncertainty measures use non-statistically derived sample questions. Using a multiphase approach, we developed a brief measure of uncertainty in rheumatic disease (bURD). In Phase 1, 132 adults with rheumatic diseases completed quantitative measures of uncertainty in rheumatic disease (MUIS-S, investigator adapted), anxiety (GAD-7), depression (PHQ-8), sickness impact (SIP), sleep quality (PSQI-Item 6), and sleep duration. An exploratory factor analysis was used to simplify the uncertainty measure for internal consistency and convergent validity. In Phase 2, 475 adults with vasculitis completed the brief measure for confirmatory factor analysis and a qualitative open-ended item assessing the primary source(s) of vasculitis-related uncertainty for reflexive thematic analysis. The brief measure had high internal consistency and good convergent validity with key outcomes for individuals living with SARDs. The brief measure is a psychometrically strong measure of rheumatic related uncertainty.