Reference values for the PROMIS^® physical function item bank version 2.0 in the general population: a multinational...

Area of Science:

• Health Outcomes Research
• Cross-Cultural Health Assessment
• Psychometrics

Background:

• Patient-Reported Outcomes Measurement Information System (PROMIS) Physical Function (PF) item bank v2.0 is a key tool for assessing physical function.
• General population-based reference values are crucial for interpreting PROMIS PF scores accurately.
• Previous reference values were primarily established in Western populations, necessitating validation in diverse global populations.

Purpose of the Study:

• To establish general population-based Korean reference values for the PROMIS PF item bank v2.0.
• To compare Korean PF reference values with those from the US and Netherlands.
• To identify potential cultural or demographic factors influencing PF scores across populations.

Main Methods:

• A representative sample of 2,124 Korean adults was surveyed using the PROMIS PF item bank in April 2021.
• Analysis of Variance (ANOVA) was used to compare mean T-scores across age groups, sexes, comorbidity status, and general health.
• Differential item functioning (DIF) analyses were conducted to compare item performance between the US and Korean populations.

Main Results:

• The mean Korean PF T-score was 55.3 (SD=9.1), significantly higher than the US (50.0) and Netherlands (49.8) general populations.
• Differences in PF scores were observed across various age and sex groups.
• Fifty-seven of 131 items showed uniform or nonuniform DIF between the US and Korean populations, indicating potential cross-cultural measurement invariance issues.

Conclusions:

• Korean adults exhibit higher PROMIS PF scores compared to US and Netherlands populations.
• Significant DIF was detected for a substantial number of items, highlighting the need for culturally adapted scoring.
• Establishing country-specific reference values for PROMIS PF is recommended globally to ensure accurate interpretation and application.