Elevated Rheumatoid Factor Associates with Dry Eye in Patients with Common Autoimmune Diseases

PURPOSE: To investigate the association and application value of rheumatoid factor (RF) in diagnosis of dry eye among patients with common autoimmune diseases. PATIENTS AND METHODS: A retrospective case-control study was conducted from Jan 1st 2019 to Dec 31st 2020, and 117 patients with common autoimmune diseases were enrolled. The concentrations of serum RF were detected. The receiver operating characteristics (ROC) curve was plotted to evaluate the values of RF in diagnosis. RESULTS: Compared with no dry eye patients, patients with dry eye (n = 59, 50.43%) had higher levels of RF (P < 0.001). Moreover, Pearson’s correlation analysis showed that RF levels were negatively correlated with Schirmer-I tear test (P = 0.004) and invasive tear film break-up time (P = 0.002), respectively. The statistically significant threshold value (cut-off points) of the RF levels for dry eye was 21.4 (IU/mL), and the areas under the curve (AUC) of RF was 0.73 (95% confidence interval [CI]: 0.639–0.821; P < 0.001) (sensitivity = 78%; specificity = 58.6%) for dry eye among patients with common autoimmune diseases. CONCLUSION: Serum levels of RF may be an independent factor for dry eye among patients with common autoimmune diseases, and they may have a high significant value and clinical application value.