Lactate Dehydrogenase as a Biomarker for Prediction of Refractory Mycoplasma pneumoniae Pneumonia in Children

BACKGROUND: Corticosteroids have been used for refractory Mycoplasma pneumoniae pneumonia and have beneficial effects. The aim of this study was to identify the biomarkers for predicting refractory M. pneumoniae pneumonia in a timely fashion to initiate steroid therapy. METHODS: This was a prospective cohort study of children with M. pneumoniae pneumonia admitted to the Children's Hospital of Fudan University from September 2012 to August 2013. Lactate dehydrogenase (LDH) and other laboratory tests, including complete blood counts, C-reactive protein, erythrocyte sedimentation rate (ESR), alanine aminotransferase, aspartate aminotransferase, α-hydroxybutyrate dehydrogenase (HBDH), creatine kinase, and creatine kinase MB, were performed on admission. Based on the definition of refractory M. pneumoniae pneumonia, subjects were divided into 2 groups: refractory M. pneumoniae pneumonia and usual M. pneumoniae pneumonia. The diagnostic values of laboratory findings were analyzed. RESULTS: In total, 653 subjects were enrolled, including 300 in the refractory pneumonia group and 353 in the usual pneumonia group. There was no significant difference in sex distribution between the 2 groups. The average age in the refractory M. pneumoniae pneumonia group was greater than that in the usual M. pneumoniae pneumonia group. Compared with the usual pneumonia group, the refractory pneumonia group showed significantly higher levels of C-reactive protein, serum LDH, serum HBDH, serum alanine aminotransferase, serum aspartate aminotransferase, and neutrophils and higher ESRs. Logistic regression showed that age, LDH, and ESR were the significant factors in predicting refractory M. pneumoniae pneumonia. In addition, LDH and HBDH were strongly correlated, and receiver operating characteristic curve analysis showed that the area under the curve of LDH was 0.718 with a cutoff of 379 IU/L, that of ESR was 0.683 with a cutoff of 32.5 IU/L, and that of HBDH was 0.691 with a cutoff of 259.5 IU/L. CONCLUSIONS: Serum LDH can be used as a biomarker to predict refractory M. pneumoniae pneumonia at the early stage of hospitalization.