VALIDATION DATA

A rigorous process combining the opinion of a large panel and data-driven methods generated from nine trials was conducted for the development of the STAR. The Delphi panel identified five core domains (systemic activity, patient symptoms, lachrymal gland function, salivary gland function and biological parameters), and 227 STAR options combining these domains were selected to be tested for sensitivity to change. 

STAR has been shown to be sensitive and specific to change: it is able to show treatment efficacy in positive trials and not to detect significant between arm differences in trials considered negative.

The test-retest reliability of each individual item has been already well described, since the STAR development relies on measurements or assessments performed in clinical practice.

The test-retest reliability of each individual item has been already well described, since the STAR development relies on measurements or assessments performed in clinical practice.

A Delphi panel identified domains to be included. The Candidate STAR and its initial variants contained 5 domains with measurement instruments attached to those domains. The experts agreed on these, and the choices are in line with the EULAR recommendations, pointing to face- and content validity.

Various designs for STAR were prepared, and a total of 227 options were selected after voting and discussion meeting. Construct validity will be further assessed using correlation analysis, discriminative ability, anchor-based analysis and magnitude of treatment effect.