Psychometric properties and general population reference values for PROMIS Global Health in Hungary

Patient-Reported Outcomes Measurement Information System-Global Health (PROMIS-GH) is a widely used generic measure of health status. This study aimed to (1) assess the psychometric properties of the Hungarian PROMIS-GH and to (2) develop general population reference values in Hungary.

An online cross-sectional survey was conducted among the Hungarian adult general population (n = 1700). Respondents completed the PROMIS-GH v1.2. Unidimensionality (confirmatory factor analysis and bifactor model), local independence, monotonicity (Mokken scaling), graded response model fit, item characteristic curves and measurement invariance were examined. Spearman's correlations were used to analyse convergent validity of PROMIS-GH subscales with SF-36v1 composites and subscales. Age- and gender-weighted T-scores were computed for the Global Physical Health (GPH) and Global Mental Health (GMH) subscales using the US item calibrations.

The item response theory assumptions of unidimensionality, local independence and monotonicity were met for both subscales. The graded response model showed acceptable fit indices for both subscales. No differential item functioning was detected for any sociodemographic characteristics. GMH T-scores showed a strong correlation with SF-36 mental health composite score (r_s = 0.71) and GPH T-scores with SF-36 physical health composite score (r_s = 0.83). Mean GPH and GMH T-scores of females were lower (47.8 and 46.4) compared to males (50.5 and 49.3) (p < 0.001), and both mean GPH and GMH T-scores decreased with age, suggesting worse health status (p < 0.05).

This study established the validity and developed general population reference values for the PROMIS-GH in Hungary. Population reference values facilitate the interpretation of patients' scores and allow inter-country comparisons.