Serum amyloid A-to-albumin ratio as a potential biomarker to predict the activity, severity, and poor prognosis of systemic lupus erythematosus.

Objectives: To evaluate the predictive value of serum amyloid A-to-albumin ratio (SAR) for active systemic lupus erythematosus (SLE), severe active SLE, and poor prognosis of SLE.

Methods: One hundred and eighty-six patients with SLE undergoing treatment in our hospital were selected. The demographic characteristics, clinical data, and disease prognosis of all patients were collected and analyzed.

Results: There were significant differences in SLEDAI, total glyceride (TG), serum amyloid A (SAA), SAR, urinary microalbumin-to-creatinine ratio (ACR), erythrocyte sedimentation rate (ESR), albumin (ALB), complement 3 (C3), anti-dsDNA, anti-Sm positive rate, and anti-dsDNA positive rate between active SLE and stable SLE patients. TG, SAR, C3, ACR, and positive anti-dsDNA were independent influencing factors of active SLE, and the odds ratio (OR) values were 2.342, 10.921, 0.832, 1.451, and 2.476, respectively. The area under curves (AUCs) of SAA, ALB, and SAR for predicting active SLE and severe active SLE were 0.743, 0.724, 0.787, 0.711, 0.686, and 0.733, respectively. The AUC of SAR for predicting the poor prognosis of active SLE was 0.719. High SAR, high ACR, low C3, and positive anti-dsDNA were high risk factors for poor prognosis. Kaplan-Meier (K-M) survival analysis showed that patients with high SAR, high ACR, low C3, and positive anti-dsDNA had shorter continuous remission time than that with low SAR, low ACR, high C3, and negative anti-dsDNA.

Conclusion: SAR had high predictive value for active SLE, severe active SLE, and poor prognosis of SLE. High SAR may be a potential marker for predicting the activity and prognosis of Chinese patients with SLE.