Psychometric evaluation of an Italian custom 4-item short form of the PROMIS anxiety item bank in immune-mediated inflammatory diseases: an item response theory analysis.

The Italian custom four-item short form from the PROMIS anxiety form 8a shows acceptable psychometric properties both from a CTT and an IRT standpoint. The Test Reliability Curve shows that this instrument is mostly informative for people with higher levels of anxiety, making it particularly suitable for clinical populations such as IMID patients.