E129 From complexity to clarity: the fibrinogen-to-albumin ratio (FAR) index illuminates lupus disease activity

Background/Aims Systemic lupus erythematosus (SLE) is a chronic multisystem autoimmune condition presenting with unpredictable varying levels of severity. Thus, constant monitoring of disease activity is required. The fibrinogen-to-albumin ratio is an emerging marker which can be used as a cost-effective surrogate marker of disease activity in countries with limited resources. Methods This descriptive cross-sectional investigation enrolled 63 lupus patients meeting 2019 ACR/EULAR criteria at a tertiary care centre between May 2023 and May 2024. Patients with diabetes, malignancies, liver disease, pregnancy, and other autoimmune conditions were excluded. Clinical assessments included comprehensive disease manifestations, while laboratory evaluation encompassed fibrinogen, albumin, complement levels, anti-dsDNA antibodies, and routine haematological parameters. Disease activity was categorised using SLEDAI-2K scores into stable, mild, moderate, and severe groups. Statistical analysis employed Pearson correlation and ROC curve methodology to determine the relationship between FAR and disease severity. Results The cohort predominantly comprised young females with a mean age of 32.2 years. Mucocutaneous manifestations predominated, affecting over 90% of participants. Mean FAR value reached 84.7 with substantial variability. Disease activity distribution showed mild activity in 35% and moderate activity in 32% of patients. Statistical analysis revealed significant positive correlation between FAR and SLEDAI scores with correlation coefficient 0.645. ROC analysis identified FAR threshold of 95.3 for detecting severe disease, demonstrating 80% sensitivity and 69% specificity. The test showed a strong negative predictive value at 97.6%, though positive predictive value remained low at 18.2%. (Table 1). Conclusion The fibrinogen-to-albumin ratio demonstrates significant correlation with lupus disease activity, suggesting utility as an adjunctive biomarker. While showing moderate diagnostic accuracy for severe disease prediction, its high negative predictive value makes it particularly valuable for excluding severe disease activity. This readily available, economical parameter can complement existing assessment tools in lupus management. Disclosure C.G. Vijay: None. V. Prasanna Parimi: None.