Background/Purpose: 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: In a cross-sectional observational study, 63 adult patients with SLE, were included in the study, conducted over a duration of one year, in the Department of Rheumatology, of a tertiary care centre. exclusion criterion included pregnancy, diabetes mellitus, active infections and presence of other autoimmune conditions. Clinical evaluation and laboratory asssessments (including fibrinogen, albumin, ESR, CRP, complements, anti-dsDNA, UPCR, and 24-hour urine protein) were recorded. Disease activity was categorized using SLEDAI-2K as stable, mild, moderate, or severe. FAR was calculated, and its correlation with SLEDAI was assessed using Pearson’s r. Receiver operating characteristic (ROC) analysis determined FAR’s diagnostic accuracy in identifying severe disease.

Results: The cohort was predominantly female (95.2%), with a mean age of 32.2±8.9 years and mean disease duration of 4.9±4.1 years. The mean SLEDAI score was 8.7±5.4; FAR averaged 84.7±40.7. FAR exhibited a strong positive correlation with SLEDAI (r=0.645, p< 0.001). ROC analysis revealed an AUROC of 0.717 (p=0.028) for FAR in identifying severe disease. At a cut-off of ≥95.3, FAR predicted severe SLE with 80% sensitivity, 69% specificity, and an impressive 97.6% negative predictive value

Conclusion: Fibrinogen-to-albumin ratio demonstrates a strong correlation with SLE disease activity and offers moderate diagnostic accuracy in distinguishing severe flares. owing to its cost-effectiveness, it can be used a practical biomarker for SLE disease activity surveillance.

Fig 1: Comparison of FAR score to predict SLE disease activity.

Fig 2: Scatter plot of SLEDAI Score and FAR Score in the study cohort.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/lupus-under-the-lens-fibrinogen-to-albumin-ratio-as-a-novel-inflammatory-index/