Regarding the article prevalence and impact of viral myocarditis in patients with severe fever with thrombocytopenia syndrome by Hao et al

We read with great interest the article by Hao et al. titled “Prevalence and Impact of Viral Myocarditis in Patients with Severe Fever with Thrombocytopenia Syndrome.”¹ The study utilized a retrospective analysis to investigate the prevalence and impact of viral myocarditis in patients with Severe Fever with Thrombocytopenia Syndrome (SFTS). The authors conducted a comprehensive dynamic analysis, comparing epidemiological data, clinical symptoms, electrocardiograms, echocardiograms, and laboratory test results between fatal and nonfatal cases. The results revealed a significantly higher incidence of viral myocarditis in the fatal group, suggesting that viral myocarditis is an important early risk factor for prognosis. While the study provides valuable insights into the high prevalence of viral myocarditis and its significant impact on prognosis in SFTS patients, several limitations warrant further discussion.

Firstly, the study primarily focused on the impact of myocarditis on prognosis, but failed to assess other potential factors, such as age, underlying conditions, and comorbidities, which could influence prognosis.² The onset of cardiac abnormalities in SFTS patients might be attributed to comorbidities. Previous studies have identified hypertension and type 2 diabetes as known risk factors for cardiovascular diseases.^{3, 4} Moreover, the presence of underlying cardiac conditions can adversely affect patient prognosis. Secondly, potential biases exist in the data collection process. Although the authors mentioned that the data were obtained from two different hospitals, they did not provide detailed information regarding the differences in patient management and treatment approaches between these hospitals. This may impact the generalizability and external validity of the study results. Thirdly, we observed inconsistencies in the study's methodology and results. The study described a dynamic analysis of risk factors associated with mortality (Table 2), but employed univariate Cox regression to assess these factors, neglecting potential interactions and confounding variables. Additionally, the authors used odds ratios (OR) instead of hazard ratios (HR) to evaluate risk coefficients, which is less appropriate for survival analysis. Furthermore, we noticed that the β-values and standard errors (SE) for CK on Day 9 and Day 10 were both zero, yet the corresponding p-values were <0.05. This is unusual, as β-values equal to zero typically indicate no association between the variable and risk, while SE values equal to zero imply complete certainty in the estimate, which is statistically unlikely. We recommend the authors reevaluate their statistical analysis to ensure the accuracy of their results. Fourthly, the authors selected 18 variables associated with myocarditis prognosis and investigated their dynamic changes throughout the disease course. However, we identified the variables Lipase on Day 9 and WBC and Neutrophils on Day 11, which seemed to be inconsistent with the variables presented in Figure 2. Lastly, in Table 3 comparing patients with fulminant myocarditis, the significant difference in sample size between the fatal (2/32) and nonfatal (1/151) groups raises concerns about the comparability and interpretation of the results. The small number of positive cases may also introduce random errors, affecting the robustness of the study findings.

In summary, this study provides valuable insights into the prevalence and impact of viral myocarditis in SFTS patients. However, addressing these limitations would enhance the reliability and clinical applicability of the findings. Further research is necessary to confirm and expand these results, which have the potential to inform clinical decision-making and patient management strategies.

Neng Wang: Writing—original draft; visualization; conceptualization. Shuai Tao: Writing—original draft; visualization; conceptualization. Liang Chen: Writing—review and editing; supervision; conceptualization.

The authors declare no conflict of interest.