Conclusions
Serum IFN-α was better in predicting in-hospital mortality compared with conventional measures of disease activity such as anti-dsDNA, complements and SLEDAI.
Methods
Serum IFN-α (ELISA) was measured in patients hospitalised for acute severe lupus in a tertiary care rheumatology unit in India and the levels were compared between survivors and non-survivors. Serum IFN-α was compared with traditional clinical and serological markers associated with disease activity to assess which better prognosticates survival.
Results
In a cohort of 90 patients with a mean Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) of 19.3 (±5.5), the mean serum IFN-α was 88±144 pg/dL. Levels were undetectable in patients with inactive disease. SLEDAI, anti double stranded DNA (dsDNA) antibody titres and serum IFN-α levels were higher and serum complement (C3) lower in non-survivors (p=0.003, p=0.017, p<0.001, p=0.029, respectively). Serum IFN-α level of 140 pg/mL had a sensitivity of 86.7%, specificity of 94.6%, positive predictive value of 76% and negative predictive value of 83.3% (p<0.001) in predicting mortality. The area under the curve for predicting in-hospital mortality was 0.25 for C3, 0.72 for dsDNA, 0.77 for SLEDAI and 0.92 for serum IFN-α. Conclusions: Serum IFN-α was better in predicting in-hospital mortality compared with conventional measures of disease activity such as anti-dsDNA, complements and SLEDAI.