Role of the C-reactive Protein-to-Albumin Ratio in Assessing Disease Activity in Elderly Patients With Rheumatoid Arthritis

TL;DR

This study shows that the C-reactive protein-to-albumin ratio (CAR) is a useful indicator of inflammation and disease activity in elderly patients with rheumatoid arthritis.

Contribution

The study demonstrates that CAR is a novel and effective biomarker for assessing disease activity in elderly rheumatoid arthritis patients.

Findings

Elderly RA patients with higher DAS28-ESR scores had significantly higher CAR values.

CAR was strongly correlated with ESR, CRP, and DAS28-ESR in elderly RA patients.

CAR showed no significant correlation with HAQ, NLR, or disease duration.

Abstract

Objective: Nowadays, one measure that is more helpful in assessing the level of inflammation than either C-reactive protein (CRP) or albumin alone is the C-reactive protein-to-albumin ratio (CAR). Our study set out to assess the CAR in elderly individuals with rheumatoid arthritis (RA) and its correlation with other parameters.

Methods: Included in the research were patients who were being followed up on for RA between January 2021 and January 2024 and categorized according to their age at the time of enrolment and assigned to one of two groups: younger patients, defined as <60 years of age, and those aged ≥60 years, who were recorded as elderly patients. The clinical evaluation of the patients and laboratory data measured for each patient included age, gender, disease duration, medications, CRP, erythrocyte sedimentation rate (ESR), albumin, neutrophil-to-lymphocyte ratio (NLR), and CAR. Disease activity was assessed with the disease activity score 28 (DAS 28)-ESR. The health assessment questionnaire was used to measure the functional status.

Results: Ninety-four patients (<60 years: 58 and ≥60 years: 36) were included. The mean age of the elderly patients was 65.80 ± 5.33 years. Female predominance was similar in both the RA groups (<60 years: 50 patients (86.2%) vs. ≥60 years: 31 (86.1%)). The distribution of biological and disease-modifying drugs did not significantly differ between the groups. With the exception of albumin, there was no statistically significant difference between the groups for ESR, CRP, CAR, NLR, or DAS28-ESR. Elderly patients with a DAS28-ESR of 2.6 and above had a statistically significant higher CAR than the remission group (3.44±3.73 vs. 2.71±5.73, respectively). There was no statistically significant difference in the NLR value of elderly patients with a DAS28-ESR of 2.6 and above compared to the remission group (3.06 ± 2.95 vs. 2.65 ± 1.38, respectively). In addition, CAR was positively correlated with ESR, CRP, and DAS28-ESR (r = 0.726, p < 0.001; r = 0.954, p < 0.001; r = 0.339, p = 0.043, respectively). However, there was no discernible correlation between CAR and HAQ, NLR, or disease duration.

Conclusion: In elderly RA patients, our study demonstrated the correlation between CAR and inflammatory biomarkers and the DAS28-ESR. According to this, CAR may prove to be a useful biomarker for assessing inflammation and disease activity in clinical settings.

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