Systemic sclerosis & Raynaud's
Differential Item Functioning on the Patient Health Questionnaire 8 by Disease Subtype, Language, Sex, and Age Among People With Systemic Sclerosis: A Scleroderma Patient‐Centered Intervention Network Cohort Study
Authors' conclusion
We did not find evidence that the PHQ-8 performs differently across SSc subtypes, language of administration, sex, and age groups.
Study context
- Population
- Participants in the Scleroderma Patient-Centered Intervention Network Cohort who completed the Patient Health Questionnaire (PHQ-8) at enrollment, April 2014 to October 2020
- Participants
- 2,191 participants
- Exposure
- PHQ-8 item functioning across systemic sclerosis (SSc) subtype, language, sex and age
- Outcome
- Differential item functioning (DIF) in PHQ-8 items across SSc subtypes
- Follow-up
- Enrollment
Methodological detailsconfirmatory factor analysis, Multiple Indicators Multiple Causes models
- Confirmatory factor analysis
- Multiple Indicators Multiple Causes models
Main finding
As reported in the abstract
DIF by SSc subtype
- No statistically significant differential item functioning (DIF) based on SSc subtype
Observational data: associations, not effects.
Further findings
PHQ-8 factor structure (confirmatory factor analysis (CFA) with several covarying error terms)
- One-factor structure supported: Tucker-Lewis Index
- 0.99
- Comparative Fit Index
- 0.98
- Root Mean Square Error of Approximation
- 0.08
DIF by language, sex and age
- Items with statistically significant DIF for language
- 1
- Items with statistically significant DIF for sex
- 1
- Items with statistically significant DIF for age
- 2
- Effect of DIF on overall PHQ-8 scores negligeable in all cases
Original publication
Differential Item Functioning on the Patient Health Questionnaire 8 by Disease Subtype, Language, Sex, and Age Among People With Systemic Sclerosis: A Scleroderma Patient‐Centered Intervention Network Cohort Study. Arthritis Care Res (Hoboken). Published 19 March 2026. doi:10.
Composed by AI from the published abstract and checked against it. How Briefs are made →