Fibrinogen to Albumin Ratio Shows Promise as SLE Predictive Biomarker

A new report has found that serum fibrinogen to albumin ratio (FAR) is a predictor of active disease, severe active disease, and poor prognosis in patients with systemic lupus erythematosus (SLE).

The study, published in Journal of Clinical Laboratory Analysis, found the ratio was a better predictor than either of the factors alone.

One problem in treating SLE is that the disease can affect a wide variety of organs, and the disease course varies significantly among patients, explained the authors. They said it is not clear why and how the disease progresses, although it is believed to be related to genetics, autoimmune system abnormalities, and endocrine hormone disorders, among other factors.

“Many studies have proved that the type and dose of hormones used in the treatment of SLE are closely related to disease activity; hence, timely and effective evaluation of activity indexes is very important,” the authors wrote.

Significant effort has already been put into the task of identifying biomarkers of disease activity. Albumin has already been linked with lupus nephritis (LN) and a poor prognosis, the authors said, and albumin to globulin ratio has been shown to be predictive of developing LN.

“The FAR as a new inflammatory marker has been proven to have good predictive value in the diagnosis and prognosis of diabetes nephropathy, acute renal injury, rheumatoid disease, and so on,” they wrote. Yet, little research shows whether FAR can predict activity and prognosis in SLE and how well such predictions might stack up to either fibrinogen or albumin alone.

The investigators enrolled 168 people with SLE from Funan County People’s Hospital in China into their retrospective analysis, which included clinical data, laboratory reports, and disease prognosis. They found links between triglycerides, FAR, erythrocyte sedimentation rate, and anti–double-stranded DNA and disease activity, and found that complement 3 had protective value.

FAR and fibrinogen positively correlated with SLE disease activity index scores, but albumin was negatively correlated, the authors said.

“The receiver operating curve analysis showed that the predictive values of FAR for active, severe active, and poor prognosis SLE were 0.769, 0.769, and 0.734, respectively, and were significant higher than fibrinogen and albumin (P < .05),” they said.

The investigators said their study was limited because they did not analyze certain other factors that might be linked with a poor prognosis, such as inflammatory factors or other thrombus markers. They also did not include organ damage in their diagnosis.

The authors said larger, broader studies could help better isolate the optimal way to predict disease activity and prognosis. For now, though, they said their data suggest that FAR is a potentially important influencer of disease severity and prognosis, but also had predictive value.

“In other words, FAR might be a potential effective biomarker to judge the severity and prognosis of SLE and have a wide range of clinical applications,” they concluded.

Reference

Dai L-L, Chen C, Wu J, Cheng J-F, He F. The predictive value of fibrinogen-to-albumin ratio in the active, severe active, and poor prognosis of systemic lupus erythematosus: a single-center retrospective study. J Clin Lab Anal. Published online July 23, 2022. doi:10.1002/jcla.24621