Utility of testing for third-generation anticyclic citrullinated peptide (anti-CCP3) antibodies in individuals who present with new musculoskeletal symptoms but have a negative second-generation anticyclic citrullinated peptide (anti-CCP2) antibody test
Authors' conclusion
Anti-CCP3 testing could improve the prediction of IA development in anti-CCP2- individuals with new MSK symptoms.
Study context
- Population
- Individuals with new musculoskeletal (MSK) symptoms and a negative anti-CCP2 test
- Participants
- 469 individuals
- Exposure
- Anti-CCP3 positive vs anti-CCP3 negative in anti-CCP2- individuals
- Anti-CCP3 positiven = 16
- Outcome
- Progression to inflammatory arthritis (IA)
- Follow-up
- 12 months
Methodological detailsunivariable and multivariable analyses
- Univariable and multivariable analyses
Main finding
As reported in the abstract
- Anti-CCP3 positive among anti-CCP2- individuals
- 16/469 (3.4%)
- Anti-CCP3 positive individuals who developed inflammatory arthritis (IA)
- 4
- Univariable: anti-CCP3 positivity associated with self-reported progression
- p<0.01
- Univariable: anti-CCP3 positivity associated with IA
- p=0.03
- Anti-CCP3 levels differed between progressors and non-progressors, all three categories
- p<0.01
- OR for progression at manufacturer's cut-off, rheumatoid arthritis (RA)
- 2.4 (95% CI 0.5 to 18.6)
- OR for progression at manufacturer's cut-off, self-reported progression
- 7.5 (95% CI 2.3 to 24.0)
- Multivariable: positivity at manufacturer's cut-off not associated with IA progression; ≥5 units cut-off associated with RA diagnosis
- p=0.02
Observational data: associations, not effects.
Further findings
Prevalence of anti-CCP3 positivity · baseline
- Positive anti-CCP3 test among anti-CCP2- individuals
- 16/469 (3.4%)
Self-reported and confirmed progression · 12 months
- Self-reported IA
- 61/469 (13.0%)
- Progression confirmed
- 43/61 (70.5%)
- Diagnosis of IA
- 30/43 (69.8%)
- Diagnosis of RA
- 13/43 (30.2%)
Multivariable analysis
- Lower cut-off (≥5 units) associated with diagnosis of RA
- P = 0.02
- Anti-CCP3 positivity at manufacturer's cut-off did not remain associated with IA progression
- Multivariable analysis
Original publication
Utility of testing for third-generation anticyclic citrullinated peptide (anti-CCP3) antibodies in individuals who present with new musculoskeletal symptoms but have a negative second-generation anticyclic citrullinated peptide (anti-CCP2) antibody test. RMD Open. Published 10 April 2024. doi:10.
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