Macrophage activation syndrome (MAS) is considered the most severe complication of adult-onset Still's disease (AOSD). This retrospective observational study was conducted to explore the clinical characteristics of AOSD-MAS patients, the risk factors for MAS in AOSD and prognostic factors in AOSD. Early changes in the clinical characteristics of AOSD-MAS were also studied.
111 hospitalised AOSD patients were included in this retrospective analysis and analysed for the features of AOSD-MAS, selecting independent risk factors associated with MAS and the correlations between clinical characteristics and patient survival.
Nine subjects (8.1%) developed MAS. AOSD-MAS patients had a higher incidence of jaundice (33.3% vs. 2.9%, p=0.007) and aspartate aminotransferase (AST) greater than 5-fold (33.3% vs. 2.9%, p=0.007). Jaundice was associated with an increased risk of MAS (OR=16.50, 95% CI: 2.73-99.82, p=0.002). The AOSD-MAS group had a higher mortality rate (55.6% vs. 8.0%, p=0.001). MAS (HR=11.22, 95% CI: 3.46-36.38, p<0.001), and white blood cell (WBC) greater than 20 109/L (HR=5.80, 95% CI: 1.09-30.92, p=0.040) were independent prognostic factors for death in AOSD patients. In the AOSD-MAS group, transaminase, triglycerides (TGs) and serum ferritin (SF) were elevated in the early disease stage, sometimes earlier than changes in blood cells in MAS.
MAS occurrence significantly reduced the survival rate of patients with AOSD. The presence of jaundice was associated with MAS occurrence. MAS and a WBC count >20 109/L were associated with a high risk of AOSD-related death. AOSD should alert the possibility of MAS when elevated transaminase, TGs and SF cannot be explained.