Vasculitis & polymyalgia rheumatica
Diagnostic significance of antineutrophil cytoplasmic antibody (ANCA) titres: a retrospective case-control study
Authors' conclusion
High PR3/MPO-ANCA titres can help to discriminate between AAV and their mimickers in patients presenting with small-calibre vasculitides, with a threshold titre of 65 U/mL and above.
Study context
- Population
- Patients over 18 years with positive MPO-ANCA and/or PR3-ANCA immunoassays, January 2010 to December 2018ANCA-positive
- Participants
- 288 participants
- Comparison
- ANCA-associated vasculitides (AAV) vs mimickers
- AAVn = 49
- ANCA-AIn = 99reference
- ANCA-On = 140reference
- Outcome
- Discrimination of AAV from mimickers by ANCA titres; cut-off titre
Methodological detailssingle-centre, observational, multivariate logistic stepwise regression
- Single-centre
- Observational
- Multivariate logistic stepwise regression
Main finding
As reported in the abstract
ANCA titres discriminating AAV from mimickers
AUC
0.83
95% CI 0.79 to 0.87
Best threshold titre, irrespective of PR3-ANCA or MPO-ANCA (U/mL)
65
NPV of threshold 65 U/mL
0.98
95% CI 0.95 to 1.00
Observational data: associations, not effects.
Further findings
Features independently associated with AAV (multivariate analysis)
| OR (95% CI) | P value | ||
|---|---|---|---|
| ANCA titre ≥65 U/mL | 34.21 (9.08–129.81) | P < 0.001 | |
| Pulmonary fibrosis | 11.55 (3.87–34.47) | P < 0.001 | |
| Typical ear nose and throat involvement | 5.67 (1.64–19.67) | P = 0.006 | |
| Proteinuria | 6.56 (2.56–16.81) | P < 0.001 | |
| 0.050.21520Odds ratio (log scale) |
ANCA-AI vs ANCA-O
- No difference between patients in the ANCA-AI and ANCA-O groups
Original publication
Diagnostic significance of antineutrophil cytoplasmic antibody (ANCA) titres: a retrospective case-control study. RMD Open. Published 13 April 2023. doi:10.
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