# Combined diagnostic value of rheumatoid arthritis-specific citrullinated protein, haemoglobin-to-red cell distribution width ratio, and anti-CCP antibody in rheumatoid arthritis

## TL;DR

This study shows that combining specific blood markers improves the accuracy of diagnosing rheumatoid arthritis.

## Contribution

This is the first study to evaluate the combined diagnostic utility of RA-CP and HRR in rheumatoid arthritis.

## Key findings

- RA-CP and HRR are independent predictors of rheumatoid arthritis.
- Combining RA-CP, HRR, and anti-CCP antibody achieves high diagnostic accuracy (AUC of 0.998).
- MPV/PC showed no significant independent predictive value but was explored for potential clinical relevance.

## Abstract

To explore the clinical significance of new haematological indicators, including rheumatoid arthritis-specific citrullinated protein (RA-CP), haemoglobin-to-red cell distribution width ratio (HRR), and mean platelet volume/platelet count (MPV/PC) ratio, in rheumatoid arthritis (RA). This study is the first to evaluate the combined diagnostic utility of RA-CP and HRR in RA.

Data from 700 subjects, including RA patients, patients with other autoimmune diseases, and healthy controls, were retrospectively analyzed. The relationships between these indicators and the risk of RA were assessed using logistic regression, correlation, and receiver operating characteristic (ROC) curve analyses.

There were significant differences in RA-CP, HRR, and MPV/PC among the three groups (p < 0.001, for all). Logistic regression analysis indicated RA-CP and HRR as independent predictors of RA (p < 0.001, for both). Moreover, RA-CP and HRR were closely associated with the clinical characteristics. In addition, ROC curve analysis revealed that the combined detection of RA-CP, HRR, and anti CCP antibody achieved the highest area under the ROC curve (AUCRA - CP + HRR + antiCCP antibody = 0.998) for the diagnosis of RA and also improved the diagnostic sensitivity (98.31%).

RA-CP and HRR were identified as independent predictors of RA, including RA-CP as a risk factor for RA and HRR as a protective factor for RA. Combined detection of RA-CP, HRR, and anti-CCP antibody could enhance the accuracy and sensitivity of laboratory diagnosis. Although MPV/PC did not demonstrate significant independent predictive value in this study, this represents the first exploration of its potential clinical role in RA.