The role of albumin-to-globulin ratio in undifferentiated arthritis: Rheumatoid arthritis versus primary Sjögren syndrome
Reyhan Köse Çobanoglu1, Taşkın Şentürk2
1Rheumatology Clinic, Aydın State Hospital, Aydın, Turkey
2Department of Internal Medicine, Division of Rheumatology, Adnan Menderes University Faculty of Medicine, Aydın, Turkey
Keywords: Albumin-to-globulin ratio, primary Sjögren syndrome, rheumatoid arthritis, undifferentiated arthritis
Objectives: This study aims to compare initial albumin-to-globulin ratio (AGR) in patients with rheumatoid arthritis (RA) and primary Sjögren syndrome (pSS) presenting with undifferentiated arthritis (UA) and to investigate whether there was a difference in terms of AGR between the two patient groups and healthy controls.
Patients and methods: Between January 2019 and December 2019, a total of 177 patients including 96 RA (10 males, 86 females; mean age: 53.6±10.8 years; range, 21 to 74 years) and 81 pSS (5 males, 76 females; mean age: 53.2±14.1 years; range, 23 to 79 years) and 82 healthy controls (20 males, 62 females; mean age: 50.5±13.6 years; range, 20 to 79 years) were included in this case-control study. Demographic characteristics, albumin, and globulin levels of all participants were recorded. The AGR, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), rheumatoid factor (RF), anti-nuclear antibody (ANA), and anti-citrullinated protein antibodies (ACPA) were assessed.
Results: The mean AGR was 1.50±0.16 in the control group, 1.48±0.24 in the RA group, and 1.30±0.23 in the pSS group, indicating a significant difference between the pSS and the other two groups (p<0.001). The receiver operating characteristic analysis revealed that the cut-off value for AGR was 1.39 (area under the curve=0.736) with a sensitivity of 0.642 and a specificity of 0.646 (p<0.001). The ESR and CRP values were higher (p<0.001), and ANA (p<0.001) and RF (p=0.003) positivity were lower in the RA group, compared to the pSS group.
Conclusion: This study findings indicate that AGR is a helpful tool in the differential diagnosis of RA and pSS presenting with UA at the time of admission, and Sjögren syndrome should be considered in case of AGR ≤1.39.