Study on Risk Factors for Severe Hand, Foot and Mouth Disease in China

BACKGROUND: Epidemics of HFMD are elevated every year globally, especially in mainland China. The disease now presents as an increasing threat to public health worldwide. METHODS: Five hundred and seventy-one EV71-infected HFMD patients in Beijing You'an Hospital were grouped by disease severity: Mild (no severe complication) (n = 221), and Severe group (complicated with brainstem encephalitis (BE), and/or pulmonary edema (PE) (n = 350)). Clinical and laboratory findings and levels of 7 serum cytokines were analyzed. RESULTS: Univariate analysis showed that (RR)>26/min (p<0.001), age<4 yo (p = 0.001), GLU>8.3 mmol/L (p = 0.008), CL<98 mmol/L (p = 0.026), and WBC>1.2×10(9)/L (p = 0.040) were associated with severe cases. Results of multivariate analysis indicated five independent risk factors (RR>26/min (p<0.001), Age<4 yo (p<0.001), GLU>8.3 mmol/L (p = 0.011), LYM>40% (p = 0.010), and ALT>40 U/L (p = 0.045)). In addition to single-factor analysis, we further analyzed the use of different combinations of risk factors. “GLU>8.3 and CL<98 and RR>26” (confidence ration (CR) = 100%) is the top indicator, followed by “ALT>40 and LYM>40% and RR>26 and Age<4 yo” (CR = 92.9%). Serum levels of IL-2, IL-4, IL-10, IFNγ, GM-CSF, and TNFα were higher in severe cases than in mild cases. A new evaluation scoring system by scoring each risk factor 1 and independent risk factor 2 was developed for early identification of severe HFMD cases. CONCLUSIONS: Five independent risk factors, along with indicative combinations of risk factors, for severe cases were identified, and a scoring system was created to facilitate the use of indicators for early medical intervention.