Korean-specific reference values for PROMIS® physical function item bank version 2.0 in general population compared to dutch and US reference values : reference values for PROMIS physical function

다국어 초록 (Multilingual Abstract)

Purpose : We aimed to obtain general population-based Korean reference values for the Patient-Reported Outcomes Measurement Information System (PROMIS) Physical Function (PF) Item Bank v2.0 and compare them with US and Dutch reference sets.
Methods : We obtained representative data from approximately 2,000 participants from the PROMIS physical function item bank in April 2021. In this study, we also used US and Dutch participants. We converted raw scores from the PROMIS PF item bank to T-scores standardized for the general US population (men (SD) 50 (10)). We compared the mean T-scores of the Dutch and American populations. Differential item functioning (DIF) analyses assess whether people from different populations with similar levels of physical function respond similarly to the items. We used ANOVA to compare the T-scores of the full items, mobility, and upper extremity by age group, sex, presence of comorbidities, and general health. We also performed multivariate linear regression to assess adjusted differences in scores.
Results : In Korean, the PF T-score was 55.3 (SD = 9.1), ranging from 28.7 to 77.6. This score was the highest compared to the mean score of 50.0 in the US and 49.8 in the Dutch general population. Differences in physical function were generally observed in all subgroups except for participants aged 75 years and older. In the PF item bank, 44/99 items were flagged for uniform or nonuniform DIF. The Korean population endorsed higher items response categories at the same level as the US population. Among the general population in Korea, older adults, women, those with lower levels of education, and those with comorbidities had lower levels of physical function compared to their counterparts in the general Korean population.
Conclusions : Considering the cultural differences between Western and Asian countries, we recommend establishing country-specific reference values on a global scale.

목차 (Table of Contents)

• Chapter 1. Introduction 1
• 1. Background 1
• 1-1. Patient Reported Outcomes 1
• 1-2. Patient Reported Outcome Measurement Information System (PROMIS) 2
• 1-3. Importance of Physical Function 4
• Chapter 2. Methods 7
• 2.1. Procedure 7
• 2.2. Participants 7
• 2.2.1. Korean participants 7
• 2.2.2. US Participants 8
• 2.3. Measurement 9
• 2.3.1. PROMIS Physical Function Item Bank 9
• 2.4. Statistical Analysis 10
• 2.4.1. T-score calculations and comparing with US and Dutch general population 10
• 2.4.2. Differential Item functioning (DIF) 11
• 2.4.3. PROMIS Physical function short form T-score and risk factor of PF 12
• Chapter 3. Results 13
• 3.1. Characteristics of study population 13
• 3.2. PROMIS PF full items references values by subgroup (Korean vs US vs Dutch) 16
• 3.3 Result of differential item functioning analyses item with ≥ 0.03 of McFadden’s pseudo R2 19
• 3.4 Risk factors for poor physical function among general population 21
• Chapter 4. Discussions 24
• Chapter 5. Conclusions 28