Routine antimicrobial therapy for severe fever with thrombocytopenia syndrome does not improve prognosis: overlap weighting analysis using a nationwide inpatient database

BackgroundSevere fever with thrombocytopenia syndrome (SFTS) is an infectious disease that presents a formidable challenge due to the absence of established therapeutic strategies that are explicitly tailored to its management. This study aimed to assess the impact of routine antimicrobial therapy on patients diagnosed with SFTS in Japan. We conducted a comprehensive retrospective cohort analysis using extensive data from a national inpatient database. Methodology/Principal FindingsThis study scrutinized data from adult patients with SFTS and categorized them based on whether they received antimicrobial treatment within the initial 2 days of hospital admission. A meticulous evaluation was carried out on a range of outcomes, such as in-hospital mortality rates, overall costs associated with hospitalization, and length of hospital stay. Overlap weighting was applied along with multivariate regression models to enhance the reliability of the findings through confounder adjustment. The outcomes showed no significant improvement in the prognosis of patients with SFTS who received routine antimicrobial therapy. The use of antimicrobials did not yield statistically significant improvements in in-hospital mortality rates or other secondary outcomes, suggesting that such therapeutic interventions may not be necessary during the early stages of hospital admission. Conclusion/SignificanceThis study underscores that the indiscriminate administration of antimicrobials does not substantively enhance the prognosis of patients with severe SFTS, hence dissuading the universal implementation of antimicrobials as a conventional component of therapeutic strategies in managing severe cases of SFTS. Author summarySevere fever with thrombocytopenia syndrome is a tick-borne infection that is endemic in East Asia, including Japan, China, and South Korea. At present, there are no effective antiviral drugs against SFTS. It has been reported that patients who received antimicrobial agents for SFTS early on had a better prognosis. To validate this study, we compared SFTS patients who received antimicrobials within 2 days of admission with those who did not, using Japanese DPC data. Overlap weighting was applied along with multivariate regression models to enhance the reliability of the findings through confounder adjustment. The results showed no difference in in-hospital mortality, hospitalization costs, or hospital days between the two groups. In conclusion, the analysis of patients with SFTS using a nationwide inpatient database revealed that routine antimicrobials did not improve patient prognosis. Further, our findings do not support the universal use of antimicrobials in patients with severe SFTS.