Objective To explore the risk factors for mortality in patients with severe fever complicated with thrombocytopenia syndrome (SFTS), and provide evidence for clinical treatment.

Methods The patients with severe SFTS diagnosed in the Department of Infectious Diseases of Anqing Municipal Hospital from 2020 to 2023 were analyzed, and the general data, clinical characteristics and most severe laboratory indicators during hospitalization were collected. The patents were divided into the survival group (n = 91) and death group (n = 33) according to prognosis.

Results The results of multivariate regression analysis showed that there were statistically significant in the age, neurological abnormalities, activated partial thromboplastin time, lactate, viral load and PLT (＜10 × 10⁹/L) between two groups (P ＜ 0.05). The ROC curve was plotted, and the area under the curve (AUC) was calculated. The AUC of age was 0.675, 95%CI (0.563–0.786), the AUC of APTT was 0.87095%CI (0.801–0.940), the AUC of Lac was 0.78495%CI (0.684–0.884), and the AUC of viral loading was 0.86095%CI (0.782–0.937).

Conclusions The age, neurological abnormalities, activated partial thromboplastin time, lactate, viral load and PLT (＜10 × 10⁹/L) are the risk factors of mortality in severe SFTS patients.