Clinical characteristics and prognostic factors in adult macrophage activation syndrome: an observational study in a Chinese cohort.

Objective: Macrophage activation syndrome (MAS), a subtype of secondary haemophagocytic lymphohistiocytosis (HLH), is a rare and life-threatening complication of rheumatoid diseases. However, the prognostic factors in adult MAS patients are still not fully elucidated, which need further investigation.

Methods: We conducted a retrospective study of adult MAS inpatients between January 2016 and January 2024. In accordance with HLH-2004 criteria, 116 patients were eventually enrolled in this study. Clinical manifestations, laboratory data, treatments and outcomes had been recorded. Influence factors associated with prognosis were analysed using logistic regression models.

Results: Seventeen of 116 (14.7%) patients died during hospitalisation. Further multivariate analysis suggested that admission ferritin <1350 ng/mL (OR=5.387, 95% CI 1.203 to 24.127, p=0.034), platelets (PLT) ≤30×10⁹/L (OR=5.387, 95% CI 1.203 to 24.127, p=0.028), alanine aminotransferase (ALT) ≥275 U/L (OR=5.732, 95% CI 1.167 to 28.167, p=0.032), central nervous system (CNS) involvement (OR=11.268, 95% CI 1.353 to 93.851, p=0.025) and procalcitonin (PCT) >0.9 ng/mL (OR=11.224, 95% CI 2.019 to 62.381, p=0.006) were potential prognostic factors for mortality of adult MAS patients.

Conclusion: Our results indicated that adult MAS patients with lower ferritin levels at admission, lower PLT counts, elevated ALT, CNS involvement and more active infection were associated with an unfavourable prognosis.